143 33 7MB
English Pages 264  Year 1974
240 24 8MB Read more
304 131 3MB Read more
The second issue of Romanov Observatory Studies investigates the unexplored effect of the Earth on the flow of time, sug
215 25 17MB Read more
The second issue of Romanov Observatory Studies investigates the unexplored effect of the Earth on the flow of time, sug
181 59 563KB Read more
260 66 1MB Read more
The Effect of the Infant on Its Caregiver
The Origins of Behavior
M ic h a e l L e w is a n d L e o n a r d A . R o s e n b lu m , E d ito r s
Volume 1 T h e E ffe c t o f the In fa n t on Its C a r e g iv e r M ic h a e l L e w is and L e o n a rd A . R o s e n b lu m , E d ito r s
The Effect of the Infant on Its Caregiver
E d ite d b y
Michael Lewis E d u c a tio n a l T e s tin g S e r v ic e and
Leonard A. Rosenblum S tate U n iv e rs ity o f N ew Y o r k D o w n sta te M e d ic a l C e n te r
A W il e y -I n t e r s c i e n c e P u b lic a tio n JO H N W IL E Y & SON S N ew Y o r k • L o n d o n • S y d n e y • T o r o n to
Chapter I, “ Contributions o f Human Infants to Caregiving and Social Interaction ’ by Richard Q. Bell is exempt from the general copyright for this title. This paper was prepared under U .S. Government auspices, and is, therefore, in the public domain.
Copyright © 1974, by John W iley & Sons, Inc. All rights reserved. Published simultaneously in Canada. N o part o f this book may be reproduced by any means, nor transmitted, nor translated into a machine language with out the written permission o f the publisher.
Library of Congress Cataloging in Publication Data: Lew is, M ichael, Jan. 10, 1937-
The effect o f the infant on its caregiver. (The Origins o f behavior, v. I) “ A W iley-Interscience publication. ” Outgrowth o f a conference sponsored by Educational Testing Service, Princeton, N.J. Includes bibliographies. 1. Infants— Congresses. 2. M other and Child__ Congresses. I. Rosenblum , Leonard A ., joint com p. II. Educational Testing Service. III. Title. IV . Series. [DNLM: 1. Child behavior— Congresses 2. Ethology— Congresses. 3. iMaternal behavior— Congresses. 4. Mother-Child relations— Congresses W1 OR687 v. 1 1973 / W S105 E27 1972] HQ774.L45
ISBN 0-471-53202-9 Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
Contributors Richard Q. Bell
C h ie f, C h ild R e s e a r c h B ra n ch
C en te r fo r C o g n itiv e S tu d ie s
N a tio n a l In stitu tes o f M en ta l H e a lth
H a rv a rd U n iv e rsity
B e th e s d a , M a ry la n d
C a m b r id g e , M a s sa ch u s e tts
I llin o is State P e d ia tr ic In stitu te
E d u c a tio n a l T e s tin g S e r v ic e
C h ic a g o , Illin o is
P r in c e to n , N ew J ersey
T. B erry Brazelton
C lin ic a l A s s is ta n t P r o fe s s o r
D ir e c to r , T h e In fa n t L a b o ra to ry
H a rv a rd M e d ic a l S c h o o l
E d u c a tio n a l T e s tin g S e r v ic e
C a m b r id g e , M a s s a c h u s e tts
P r in c e to n , N ew J ersey
C. Dreyfus-Brisac C e n tre d e R e c h e r c h e s B io lo g iq u e s N e o n a ta le s
Mary Main J oh n s H o p k in s U n iv e rsity B a ltim o r e , M a ry la n d
H o p ita l P o r t-R o y a l U n iv e r s ite d e P aris P a ris , F ra n ce
Leonard A. Rosenblum D ir e c to r , P rim ate B e h a v io r L a b o ra to ry State U n iv e rs ity o f N ew Y o rk
Selma Fraiberg D ir e c t o r , C h ild D e v e lo p m e n t P r o je c t
D ow n sta te M e d ic a l C en ter B r o o k ly n , N ew Y o r k
U n iv e rs ity o f M ic h ig a n A n n A r b o r , M ic h ig a n
Gerald P. Ruppenthal R e g io n a l P rim a te R e s e a r c h C en ter
Anneliese F. K orn er S e n io r S cie n tis t D e p a rtm e n t o f P s y ch ia tr y S ta n fo rd U n iv e rs ity S c h o o l o f M e d ic in e S ta n fo r d , C a lifo r n ia
U n iv e rsity o f W a s h in g to n S e a ttle , W a s h in g to n
Gene P. Sackett
J. M. Tanner
R e g io n a l P rim a te R e s e a r c h C e n te r
In stitu te o f C h ild H ea lth
U n iv e rs ity o f W a s h in g to n
U n iv e rs ity o f L o n d o n
S ea ttle, W a s h in g to n
L o n d o n , E n g la n d
Daniel N. Stern
Kenneth P. Youngstein
A ssista n t P r o fe s s o r o f P s y c h ia try an d
State U n iv e rs ity o f N e w Y o r k
C h ie f, D ep a rtm e n t o f D e v e lo p m e n ta l
D o w n sta te M e d ic a l C e n te r
P h y s io lo g y N ew Y o r k State P s y c h ia tr ic In stitu te N ew Y o r k , N ew Y o rk
B r o o k ly n , N e w Y o r k
Series Preface “ The childhood shows the man, as morning shows the day. ” M ilto n , P a r a d is e R e g a in e d
N one can doubt that the study o f man begins in the study o f ch ild h ood . Few w ou ld contend that the new born lacks the challenge o f his evolutionary heritage. This series addresses itself to the task o f bringing together, on a continuing basis, that con flu en ce o f theory and data on on togen y and phylogeny w hich w ill serve to illustrate The Origins o f Behavior. W hether our so cia l, human, and professional concerns lie in the p sych olog ical disorders o f ch ild h ood or adulthood or m erely in the presum ptively normal range o f expression in developm en t in different cultures, varied environm ents, or diverse fam ily con stellation s, we can never hope to discern order and regularity from the mass o f uncertain observation and groundless speculation if we fail to nurture the scientific study o f developm en t. Fortunately, the last tw o decades have seen an enorm ous bu rgeoning o f effort toward this end, both at the human and nonhuman level. H o w e v e r, despite this grow th o f effort and interest, no single means o f p oolin g our g row in g k n ow led ge on developm en t in children and animals and com m un ica tin g that fusion o f material to the broad scientific com m unity now exists. This series seeks to fill the gap. It is our intention to have each volum e deal with a specific theme that is either o f social or o f theoretical relevance to developm ental
In keeping with the integrated perspective that we
con sider to be vital, and to provide a m eaningful context within w hich these issues m ay be con sidered, each volu m e in the series will contain a broad range o f material and w ill seek to en com pass theoretical and sound em pirical studies of the behavior o f human infants as w ell as pertinent aspects o f animal behavior with a particular em phasis on the primates. It is our v iew , furtherm ore, that not on ly is it necessary to focu s our interest on both human infants and animals, but that the levels o f analysis w hich w ill explicate the processes o f developm ent that are our con cern must ultimately in volve the study o f behavior at all levels o f d iscou rse. Thus studies o f developm ental significance may be found in genetic, p h y sio lo g ica l,
m o rp h o lo g ica l, d y a d ic, and societal levels and an increased
interdigitation o f these separate disciplines is am ong the m ajor goals o f this series. vii
Series P refa ce n light o f the diversity o f topics to be con sidered, the breadth o f material to be cov ered , and the variety o f orientations that w ill be included in these discourses on the origins o f human behavior, we expect this series to serve the needs o f the broad social scien ce com m u n ity, not m erely o f those interested in behavioral developm ent alone. Just as the series itself will draw upon the k n ow led ge and ob^etri pSychol° S lsts’ ethologists, so ciolog ists, psychiatrists, pediatricians, obstetricians, and devoted scientists and clinicians in a number o f related disciplines, it is our hope that the material in this series w ill p rovide -both stimulation and guidance to all am ong us w ho are concerned with m an, his past his present, and his future. P ’
M ic h a el L ew is L e o n a r d A . Rosenblum June 1973
Preface The them e o f this volu m e centers in the effect that the infant m ay have on its caregiver. For m any years workers in child developm ent have neglected the significance o f the interaction betw een m other and infant, and in a sense the subtle contributions that each m akes to the other in shaping their on g oin g dyadic behavior. There have been few v o ice s stressing the necessity o f observin g both partners in this dyad ic b on d . It is important that w e now focu s attention on the im pact o f the infant as a sou r ce o /t h e form ation , regulation and indeed even the m alevolent distortion o f the ca reg iv er’ s behavior. A s the original chapters included in the current volu m e adm irably attest, this serious gap in our early studies o f ch ild developm en t has begun to be filled. A s a result w e have begun to see in quite ex p licit terms that the infant even at birth is no mere passive recipient o f stimulation from those around him , ready to be m olded like clay on the potters w h eel. A s a reading o f the chapters w ill clearly indicate, whether w e seek to account for the m other or caregiver as the essential force in shaping the child through her interaction with it, w e have clo se d our eyes to half the picture. It is notew orthy that in keeping with the m ajor tenet o f this series, the current volum e en com passes the effect o f
infant defects on caregivers from
a variety o f
v iew p oin ts, using both humans and m on keys as subjects, w hile also exam ining in
m o rp h o lo g y , p h y s io lo g y , and beh avior. Thus, as w e expect o f the series as a w h o le , the material contained should prove o f interest to workers in a w ide array o f d iscip lin es, from anthropoligists to z o o lo g ists, as w ell as the diverse array o f w orkers in p s y c h o lo g y , psychiatry, and pediatrics. This first volu m e grow s out o f a con feren ce sponsored by Educational Testing S erv ice, P rinceton, N ew Jersey. T he papers presented here.represent both the original view s o f the authors as w ell as the effects o f three days o f discussion betw een the contributors them selves and several invited discussants. In this regard the editors and contributors w ou ld like to express their appreciation to the fo llo w in g participants: D r. B everly B irns, Dr. H ow ard A . M oss, Dr. Harriet L. R h ein g o ld , and Dr. L eon J. Y arrow . In addition to the incorporation o f the ideas and criticism s
in the contributions
them selves, the introductory chapter o f this b o o k represents an effort to integrate the m ost salient features o f this material. E ach o f the subsequent volum es in this series w ill contain similar ov erview s o f the issues under consideration distilled ix
P re fa ce
by the editors from the papers and discussions held at these m eetings; thus we h op e, each volu m e w ill be a m ore coherent arena o f discourse. M ich a e l L ew is L e o n a r d A . R osen blu m Princeton, N ew Jersey B rook lyn , N ew Y ork July 1973
Contents In tr o d u c tio n 1.
C o n tr ib u tio n s o f H u m a n In fa n ts to C a r e g iv in g and S ocia l In te r a c tio n R ichard Q. Bell C ontribution o f the you n g to parent life-support and protection activities
C ontribution o f the you n g to the social interaction system
General principles Sum m ary
R eferen ces 2.
A n In te r a c tio n a l A p p r o a c h to the M o th e r -In fa n t D y a d M ic h a e l L ew is and Susan L ee-P a in ter M o d e ls o f interaction M eth od
L evels o f data analysis Results
D iscu ssion
R eferen ces
T h e O r ig in s o f R e c ip r o c it y : T h e E a rly M o th e r -In fa n t In te r a c tio n T. B er r y B razelton, Barbara K o slow sk i, and M a r y Main E th ological description o f early mother-infant interaction
C y clica l nature o f the interaction
M o th e r’ s role 64 C om m u n ication with neonatal infants
D iscu ssion
R eferen ces
V a r ia b ility o f G r o w th an d M a tu r ity in N e w b o r n In fan ts J. M . Tanner
Variation in birth w eight and length
Variation in physical maturity at birth
Variation in shape and b od y com p osition Sum m ary 99 R eferen ces
T h e E ffe ct o f the I n fa n t ’ s S ta te, L evel o f A r o u s a l, S ex , a n d O n to g e n e tic Stage on the C a r e g iv e r A n n e lie s e F . K o r n e r E ffect o f the infant’ s caregiver 105
E ffect o f the infant’ s sex on the caregiver
E ffect o f the infant’ s on togenetic stage o f developm ent on the caregiver 114 Sum m ary and con clu sion s R eferen ces 118
O rg a n iz a tio n o f S leep in P re m a tu re s: Im p lic a tio n s fo r C a re ta k in g C. D reyfu s-B risa c Sleep states in premature and term infants
External influences on sleep o f prematures The premature and its environm ent
Influence o f prematurity on late organization o f sleep 134 D iscu ssion and con clu sion R eferen ces 137
D e v e lo p m e n ta l C h a n g e s in C o m p e n s a to r y D y a d ic R e sp o n se in M o t h e r an d In fa n t M o n k e y s L eon a rd A . Rosenbluin and K en neth P. Youngstein C aregiving in nonhum an primates Initiation o f maternal caregiving
The infant’ s elicitation o f caregiving R esponses to dead infants
Infant characteristics and maternal caregiving
to experim entally
Results and discussion
A theoretical m odel o f com pensatory dyad ic response 158 R eferen ces
S o m e F a c to r s In flu e n cin g the A ttr a c tio n o f A d u lt F em ale M a c a q u e M o n k e y s to N eon ates G e n e P. Sackett and Gerald C. Ruppenthal The self-selection circus test
N orm ative studies: Validation o f the preference technique
E ffects o f the adult fe m a le ’ s rearing history
C on dition s under w hich the m other reared her infant 172 E ffects o f confined rearing space E ffects o f infant’ s age at separation Effects o f aging
M oth er
Sum m ary and con clu sion s R eferen ces
In fa n t
at P la y :
D y a d ic In tera ction
In v o lv in g F a c ia l, V o c a l, an d G a z e B eh a v iors Dan iel N . Stern D evelop m en tally unique aspects o f gaze and som e early functions o f gaze
Play activity betw een m other and infant M eth od
D iscu ssion Sum m ary R eferen ces
206 210 211
B lin d In fa n ts an d T h e ir M o th e r s : A n E x a m in a tion o f the S ig n System Selma F raiberg S elf-observation s The sam ple
O bservational procedures
T he absence o f an eye language T he sm ile language
T he absence o f differentiated facial signs T he hand language
The vocal dialogue 229 The achievem ent o f human bonds R eferen ces
Contents S ocial R e sp o n se s o f A n im a ls to In fan ts w ith D efects Gershon B erkson A bnorm al animals in natural populations
Social responses to defective individuals
R esponses o f m onkeys to infants with visual defects 237 C onclusions R eferences A u th o r In d ex S u b je ct In d ex
M IC H A E L L E W IS Educational Testing Service
LE O N A R D A. R O SE N B LU M Downstate M edical Center
W e have ch osen the effect o f the infant on the ca re g iv e r1as the theme o f the first volum e o f this series because w e w ish to underscore a very important point, often paid lip service in the past but too frequently neglected in actual research and theory:
N ot on ly
is the infant or child influenced by its social, political,
e c o n o m ic , and b io lo g ica l w orld , but in fact the child itself influences its w orld in turn. H istorically, it is true that m ost em phasis has been placed on the effect o f the social and physical environm ent on the developm ent o f the infant and child. For exam ple,
the literature is replete with exam ples o f h ow
behaviors affect specific infant functions. This emphasis needs to be corrected, lest w e con clu d e that the infant is a passive organism constantly being affected but having no effe ct, constantly being altered but producing no change itself. Such a m odel o f the d ev elop in g child in fact is not on ly false but is on its face illog ica l. Even the m ere size o f a child in terms o f its height and w eight, 'W e use the term caregiver to refer to the person responsible for giving care to an infant. The neuter quality o f this term pays heed to the fact that males may well be just as capable o f giving care as fem ales, and fail to do so, in humans at least, only because o f societal pressures. In any event it has not been demonstrated that males are unequal to this task. W hile using a nongender term we recognize, h ow ever, that most o f the work reported and all the chapters included in this volum e look primarily at female caregivers. This immediately suggests that we have little information about male caregivers, their behavior, the patterns o f their interactions, or infants’ specific responses to them. M oreover, our understanding is further limited in that most o f our information deals with a d u lt females as caregivers rather than individuals o f any other age categories. Clearly, our ultimate understanding o f the nature and dynamics o f caregiving must include more broadly representative age and sex classifications. Finally, and somewhat arbitrarily, we have chosen to use the term “ caregiver” rather than “ caretaker,” the form er being the less ambiguous term. For us the person responsible for providing the care o f the infant or young child is a caregiver, rather than one w ho takes upon himself the cares o f the child. It seems to us that the term caregiver m ore directly reflects what in fact occurs, and as such w e prefer to use this term.
M ichael Lewis and Leonard A. Rosenblum
im m ediately and with no other inform ation, acts upon an approaching adult set upon engaging in social interaction. Thus our task is not so m uch to con v in ce the com m u nity that the organism affects and alters its caregivers, but rather to determ ine what m ight be the manner o f this effect and h ow it might be m easured. H ence one can q u ick ly bypass the issue o f whether the infant affects its caregiver and deal with h ow and perhaps even w hy it does so and with what specific effects. Several strategies are available and in fact m any have been em p loyed in the material included in this volum e. O ne such strategy suggests that w e consider different aspects o f the infant, vary these along som e know n and defined dim ension, and observe the effect on caregivin g. O ne w ay o f doin g this is to alter a particular attribute experim entally. B erkson, as described in this v olu m e, produ ced lesions in the eyes o f infant m on k eys, greatly reducing their visual acuity, and observed the effect on the caregivers. Fraiberg sim ilarly observed blind human infants, although c o n genitally blind from birth. R osen b lu m , again studying m on k eys, rendered the infant u n conscious and im m obile and in this w ay studied changes in caregiving behavior. Still another w ay o f approaching the problem is to look at som e o f the m ore b io lo g ica l dim ensions that characterize the infant, variables such as sex , physical stature, state, or arousal level, and to consider their real and potential im pact on the caregiver. In the present volu m e Tanner, K orner, and D reyfus-B risac turn their attention to these considerations. One m ay also look at a specific maternal behavior in terms o f experim entally presented differences in infant characteris tics. Sackett, for exam ple, using several types o f nonhuman prim ates, exam ined approach behavior as a function o f a variety o f attributes— the species or age o f the infant for exam ple. In this case the approach behavior o f the adult is taken as the reflection o f caregiving potential. A ll these various strategies and dim ensions have in co m m o n the som ew hat bifurcated study o f single elem ents in what is a dyadic system . W h ile form er research tended to stress the effect o f the parent on the child , these studies stress in turn the effect o f the child on the caregiver. L ew is, B razelton, and Stern suggest that none o f these m ethods really captures the dynam ic elem ents o f the developm ental system . For them the phenom enon under study is dyad ic in nature, and on ly through dyadic study can w e co m e to assess the nature o f each participant s contribution. For these three authors there is on g o in g effectiveness a chain w hich must be studied in terms o f its integrity rather than through observation o f its com pon en t elem ents.
Stern and Brazelton ob serv ed the
m other-infant interaction in a fixed situation, w hile L ew is observ ed a free-field interaction o f the very y ou n g. A ll three offer a w ide variety o f m easures, w hich it is h oped capture what they b elieve to be the interactive, dyn am ic, and changing phen om en on o f a dyadic relationship. Our com m ents suggest that the volum e divides itself into several sections,
although w e have not form ally divided it as such. The first portion, including articles by B ell, L e w is, and B razelton, deals with general issues in the study o f the effect o f the infant on its caregiver, as w ell as various m odels and approaches to a dyad ic study o f m oth er-in fa n t. Stern’ s chapter, w hich also deals with these issues, is prim arily con cern ed with the visual response system and so is placed in the section dealing with this specific dim ension. H ow ever, Stern offers som e interesting and important measurement procedures for the study o f dyadic relationships.
R osen blu m ,
a specific phenom enon,
approaches the interaction issue by look in g at the effects o f a sudden and com plete lack o f responsiveness, brought about by induced u nconsciousness, as it affects both the caregiver and infant on different occa sion s. In this sense he is sensitive to the position that it is necessary to study both com ponents in order to generate an interactive m od el. In his discussion R osenblum offers us such an interactive m od el. W hether or not dyadic relationships can be studied in pieces by look in g at the elem ents one at a time still needs to be explored. H ow ever, it offers us a clear exam ple o f how such research might be undertaken. The secon d portion o f the v olu m e, w h ich com prises the w ork o f Tanner, K orner, D rey fu s-B risac, and Sackett, deals with a w ide variety o f subject variables including state, sex, prematurity and sleep, age, and species. Each o f these is an important dim ension o f the infant, w hich should affect the caregiver. C learly, a sleeping infant affects its caregiver’ s behavior differently than one w ho is awake and alert. A responsive infant is m ore likely to produce continuing interaction than a nonresponsive on e. Im plicit in these studies is the assumption that there exist relatively stable dispositions or characteristics o f the infant. For an interactionalist these assum ptions m ay be questioned, especially in the open in g o f life, when individual stability is hard if not im possible to demonstrate and variables
as temperam ent are
to define to
e v e r y o n e ’ s satisfaction. Som e variables, such as sex or age, for exam ple, on the surface at least appear not to be quite so subject to this problem ; but even here the ca reg iv er’ s interpretation o f the m eaning o f an infant s sex or age may w ell be critical in the determ ination o f the ca reg iv er’ s response. The final chapters, those o f Fraiberg, Stern, and B erkson, deal m ostly with the visual system — Stern from a dyadic point o f v iew , Fraiberg by considering language
alternative to the visual, and Berkson in terms o f the
adaptations o f free-ranging primates to visually debilitated young in their midst. T he reader m ay find m ore salient divisions o f the articles present here. The structure suggested above is an attempt to suggest som e lines o f interrelatedness o f the chapters and is not intended to im pose constraints upon a further possibility fo r m ore diverse interpretations. W h ile on e can never h ope to capture and summarize all the issues raised by the articles included in this v o lu m e , w e attempt to present four m ajor problem areas w hich em erge repeatedly in various form s and contexts. T o be sure, m ost often questions and issues are raised rather than answered. The fo llo w in g discussion
Michael Lewis and Leonard A. Rosenblum
underlines this uncertain state o f our k n ow led ge. The four issues con sidered are: (1 ) b io lo g ica l and cultural (or experiential determinants in d ev elop m en t), (2 ) the prim acy o f particular sense m odalities in influencing interactive p rocesses, (3) the characteristics o f the stimuli exch anged in the dyadic interaction, and (4 ) the interactive process itself.
B IO L O G I C A L A N D C U L T U R A L IS S U E S There is never a discussion o f any topic in p s y ch o lo g y that does not sooner or later arrive at a nature-nurture or biolog y -cu ltu re discussion. The m ajor form s in w hich the issue arises regarding the effect o f infant on caregiver are tw o: the specific characteristics o f individual infants and the differences am on g infants, and how and w hy infants and caregivers behave as they d o. Let us first consider individual characteristics. O ne m ethod for considering the e ffect o f the infant on its caregiver(s) is to try to describe with precision the observable characteristics o f each. This approach im plies that, b y k n ow in g the detailed features o f each partner, one is capable o f describing what w ill transpire when they are placed together. It is assumed furthermore that there are stable and m easurable characteristics o f both m em bers. T hese characteristics can be the product o f either experien ce or genetics. Such characteristics as height and w eight produce little discussion or heat. It is assumed that early in life, at least, they are prim arily b io lo g ica lly determ ined (although w e also know they are subject to diet, e tc .) and that they affect the ca regivers’ behavior in numerous w ays. Such differences as gender, h ow ev er, raise considerably m ore contention. D o es the designated sex o f the child produce differences in the caregiver prim arily due to cultural bias, or d o male and fem ale infants act innately different and therefore produce differential behavior in the caregiver, w hich in turn is responded to in a differential fashion by the infant? These questions and their corollaries have not yet been answ ered, but data do exist indicating that as early as on e can demonstrate sex differences in infant behavior, or even explicit gender designation, one can also dem onstrate differences in som e aspects o f the ca reg iv er’ s behavior. Other characteristics o f both infants and caregivers, such as arousal level species characteristics, and so on , are also discussed in this v olu m e. C lea rly ’ h ow ev er, w e do not at present have en ough inform ation on any o f the various dim ensions
U ndoubtedly, o f even m ore im portance than these ob v iou s physical characteris tics
or personality characteristics o f the caregiver
d ev elop in g infant. It is through the m ediation o f these elem ents that each organism com es to interpret the action o f the other. A n “ op tim istic” m other m ay interpret the withdrawal o f infant gaze as an interest in som ething else, whereas another mother m ight interpret this to mean that the infant is tired o f look in g at
H o w e v e r, the larger theoretical issue rem ains: Can one understand the dyadic relationship b y studying these elem ents in isolation? If this is to be our strategy, w e must be confident that the characteristics being measured have at least som e significant degree o f stability, at least across som e determinable temporal internal or repeatable circum stances.
O n this score w e must admit som e
pessim ism . The in fan cy data to date do not strongly suggest m any such stable constructs. This strategy o f look in g at elem ents unilaterally m ay be useful if w e are able ultim ately to incorporate these characteristics within an interactional fram ew ork. Thus it appears that if particular characteristics o f individuals m ay be fit into a m odel o f characteristic level, situational content, and ou tcom e possibilities, measurem ent o f such features m ight be useful after all. This is, h ow ever, a con siderab ly larger task than the sim ple description o f individual characteristics, h ow ev er detailed and precise they m ight be. The secon d problem raised under the nature-nurture banner is the question h ow and w h y organism s behave the w ay they d o to each other. This is a most important issue, given on ly passing notice in the chapters. There is a variety o f m odels w h ich can be e v ok ed to account fo r the occurrence o f behavior, and w e exam ine
them— e th o lo g y ,
con d ition in g sense, and id e o lo g y . The eth ologica l position argues for a predom inantly b io lo g ica l basis for the occu rren ce
infant’ s responses,
including facial expressions, b od ily
p osition s, v o ca l prod u ction , and so on . M o reov er, this view suggests that many o f the ca reg iv er’ s responses are in som e sense prew ired and are “ released” at the appearance o f a particular infant beh avior, or v ice versa. For exam ple, it might be argued that a human infant’ s cry is innately aversive to other humans. This aversive quality is independent o f any cultural factors and produces behavior in the caregiver “ d esig n ed ”
to “ turn it o f f . ” W ithin this m odel w e must also
con sid er that som e responses o f the caregiver are better than others in producing norm al grow th and adaptive potential. For exam ple, w hile a flashing light may serve to rein force an infant’ s v ocaliza tion , it m ay be that a caregiver’ s responsive voca liza tion is the best stimulus to p rov id e, best here being defined in terms o f subsequent use o f vocalization (language and com m unication). This eth ological position has increasing appeal and requires considerable naturalistic observation o f the type, for exam ple, incorporated in B razelton’ s, Stern’ s and L e w is ’ material. The actual degree to w hich this is possible in view o f the fact that the caregiver is observed and therefore not entirely
question that must be dealt with in future w ork. The learning o f behavior is so w ell established that little new m ay be said for or against its unquestionable significance. W h ile the ability o f very young infants to be cla ssica lly con dition ed
is in som e doubt, there is no question that
instrumental learning can be dem onstrated very early. This being the ca se, it is clear that the infant can learn to m o d ify its behavior in terms o f environm ental
Michael Lewis and Leonard A. Rosenblum
dem ands. O f interest is the learning o f the ca reg iv er’ s behavior. Can they easily learn to alter their behavior in light o f the infant’ s responses? The interaction data collected and reported in several o f these chapters indicate that m others are able to alter their behavior in terms o f what their infants d o. H ow ev er, although there are con dition in g studies o f infants, there are no com parable ones for adults. W hat are the learning processes through w hich caregivers g o , and what factors control them ? Can caregivers’ sm iles be con d ition ed ? W hat are the m inim um cu es? T hese m ay be important questions to explore. The final consideration is id e o lo g y , by w hich w e mean the cogn ition s in volved in plans and strategies. These id eolog ies are often what is considered when w e talk o f social class or culture. The term id e o lo g y is intended to mean the plans and strategies (including intentions) that exist for both the infant and its caregivers. This approach evokes the con cep t o f deliberate acts and seeks to explore the strategies used to prod u ce specific ou tcom es. For exam ple, som e mothers respond to an infant’ s cry with v ocalization , h old in g, and rock in g ; others by just look in g at their infant. W e k n ow little about the behavior unless w e understand the id e o lo g ica l constraints that m ay underlie it. For ex a m p le, w e m ight talk about one m other as m ore “ re sp o n siv e .” In on e sense at least this might not be true, in that both behave in som e fashion toward their infants. Investigation o f their id e o lo g ie s, h ow ev er, reveals that on e wants to teach the infant that it cannot have what it wants all the time— “ let him cry it o u t” — w hile the other seeks to protect it from a “ c o l d ” w orld for as lon g as p ossib le. Both parents seek to teach their infants, and both are resp on sive, but their id eolog ies result in different behaviors. W hat m ight be the con sequ en ce o f sim ilar maternal behavior derived from different id e o lo g ie s ? This, o f cou rse, w e d o not k n ow . or do w e know about the plans, strategies, and cogn ition s o f the infant. W hat m ight these b e ? A nd h ow do they dev elop and ch an g e? Thus w h ile our inform ation on adult id e o lo g y and behavior is conceptualization o f infant id e o lo g y is totally lacking.
T o sum m arize, w e must con clu d e that w e understand little o f w hy or h ow the behaviors o f the infant and its caregiver co m e about. A t this point w e must be satisfied with actual description (this must include m ore than what w e have don e
situation variation, for ex a m p le), w hile con siderin g further the ultimate
integration o f the material provided b y each o f these overlapping approaches.
S E N S E M O D A L IT I E S IS S U E S inVe.S" ' f lors have cen,ered 'h eir interest on the visual m o d e , and it is recogm zed that viston, both the infant's and ca reg iv er’ s, is indeed a m o .mportant m ode. H ow ev er, it is logieal that w e consider m ore ex p licitly the issue w t its tsUw da In iT /h V ST r ythe r role emSo f^ the ,hCseveral hUma"sensory m oda lities, it is with w or orld. thmkmg about
useful to con sider the division betw een distal and proxim al sensory input. Distal refers to stim ulation or stimuli at a distance, w hich are experienced primarily through the visual, auditory, and olfactory m odalities (the last-m entioned may operate, in som e instances, on ly proxim a lly, but has the potential for distal stim ulation). Proxim al stimuli are experien ced through the tactile, kinesthetic, and gustatory m odalities. This d iv ision , o f course, does not im ply that visual and auditory stimuli m ay not be provided w h ile infant and caregiver are in close p roxim ity or con tact, but rather that on ly these sensory inputs, and to som e degree olfa cto ry stimuli as w ell, m ay be provided w hile the m em bers o f the dyad are ph ysically apart. U nfortunately, there has been very little w ork on the diverse means o f experien cin g the social and ph ysical environm ent during developm ent, m ost o f the theoretical burden having been placed on the visual and auditory system s. This is a particularly striking deficit, in that for the human (and other primate) infant (unlike the adult) so m uch o f its contact with its environm ent is experien ced through tou ch , taste, and m ovem ent. It is clear that m ore inform ation must be gathered to observe the use o f the other m odalities. Fraiberg, by studying blind infants, allow s us to explore alternative “ languages” o f com m u n ica tion , and it b ecom es clear that the use o f alternative m odalities qu ick ly can b e co m e available to both parent and child if they learn their signs and use. This material suggests, h ow ever, that unless intervention
(learning) is instigated, m ost caregivers do not automatically
b e co m e sensitized to the use o f b o d y m ovem ent instead o f facial expression. B erk son ’ s data also suggest that primate infants in the w ild are able to survive (presum ably
m inim al
environm ent is not ov erly harsh. H ow ev er, these exam ples are extrem e, and we need to ex p lore the use and organization o f the various m odalities as they occu r in “ n orm a l” developm en t. L ew is, after look in g at a w ide variety o f responses and their interactions betw een infant and m other, discusses the relationship betw een a tactile contact and a visual regard. Just this type o f m ultisensory data is im portant. Study o f the different m odalities separately may fail to provide a com p lete hence accurate picture, although detailed studies within a m odality may w ell be the necessary prelude to the study o f the entire multisensory system . For ex a m p le, Stern gives us an excellent description o f the visual regard system but om its potentially relevant behaviors im pinging upon other than visual sense receptors. O ne m ay anticipate that as the function o f each such intramodality system is defined w e w ill be able to con sider the w h ole array o f multisensory exch an ge in the dyad. A n infant not on ly look s at what it sees, but looks toward what it hears. Still another point that was not brought up in these chapters concerns the use o f various sensory m odalities. It must also be kept in m ind that different m odalities m ay be
used to experien ce
the w orld
in different manners, and that the
integration o f these experien ces results in a m uch higher level o f organization.
Michael Lewis and Leonard A. Rosenblum
N o inform ation is available as to how this organization d ev elop s. W e cannot even answer questions con cern in g the relationship o f ob ject perm anence over different m odalities. W e strongly suggest therefore that m odalities other than the visual m od e be explored further, and that exploration o f these m odalities consider the interaction and com plem entarity o f the various systems.
S T IM U L U S M E A N IN G IS S U E S W e have discussed stimulus issues in m uch o f what w e have already said. The conceptualization o f elements versus interaction is in som e sense a discussion o f what the infant and caregiver respond to. W hat w e n ow consider are tw o or three issues relating to the general topic o f stimulus m eaning. The first issue concerns stimuli as they relate to situation. It is w id ely held that a stimulus event, for exam ple, a touch or vocalization or som e com bin ation , is often treated as if it carries the same m eaning regardless o f context. W e maintain that this is not necessarily true, and that it is necessary to study the contextual or situational setting as w ell as behavioral events them selves. Thus a stimulus event m ay change its m eaning for both infant and caregiver, depending on the situation. A sim ple exam ple m ay suffice. The infant cries— in one case it has just been fe d , in the other it is feedin g time. The caregiver through contextual cues realizes that in the form er case the infant is in need o f a burp, w hile in the latter the infant is hungry. The behavior o f the infant is the sam e, but the m eaning o f the
caregiver s behavior are not as easily found. For exam ple, a caregiver m ay pick up an infant because she thinks the infant wants to be held, whereas another time the caregiver picks up the infant because she wants to hold it. At issue then is the m eaning o f behavior. O ne w ay this can be explored is to observe given behaviors in different contextual situations. Parenthetically, it m ight be m entioned that context m ay be very important for a d evelopin g organism . The infant m ay utilize behavior-context situations to learn m eaning. A nother stimulus issue in volv in g the relationship betw een stimuli has been m entioned b efore. It seems quite plausible to us that som e stimuli m ay have m ore salience in eliciting or affecting behavior than others. For exam ple, as suggested in
a prior section ,
a v o ca liz a tion -v oca liz a tion
interaction m ay be m ore important than a v oca liza tion -oth er. That there already exists cerebral hem isphere selectivity for human sounds suggests that such a relationship m ay w ell hold. Lew is and Stern believe that there m ay be m ore o f these types o f adaptive pairings. This o f course suggests that som e interactive events are m ore b io lo g ica lly adaptive. One might account for this in at least tw o w ays. The first explanation is an eth ological one w hich argues that a particular in ant/caregiver
m em ber’ s response repertoire. T o h old this v iew one w ould need to show this to be invariant o v er situation (it b e co m e s difficult to maintain the releaser view when the relationship holds on ly in select situations) and to demonstrate that it is invariant o v e r the human species. The second view holds that the pairing relationship is a learned on e , in that o n ly specific behaviors produce desired ou tcom e s, or that these o ccu r on ly under certain specifiable conditions. These possibilities must remain conjectural in that neither has been explored. The final point w e w ish to attend to deals in a broad w ay with the general nature o f the stimuli w e refer to w hen w e talk o f the infant and its caregiver. It must not escape our notice that generally w e are talking about human bein gs, and putting aside for the m om ent other aspects, specifically considering the fa ce o f the hum an. W e think it safe to assume that w hile other aspects o f the human form impart m eaning, the human face is b y far the m ost outstanding source o f inform ation. Stern makes this point, and w e think it well taken that the human fa ce is a rather unique co m p le x o f stim uli, at on ce variable and constant. W hat a rem arkable characteristic that the face can change so m uch and yet remain the sam e. That it can express such a w ide range o f feelin g and still be the same face must be o f crucial im portance for the y ou n g infant. W ith this in mind w e suggest that careful studies be made o f fa ce s, the infant’ s as w ell, in order to better understand a m ajor source o f stimulus change and constancy.
I N T E R A C T I O N M E A S U R E M E N T IS S U E S M ost o f the chapters in this volu m e show som e concern at least with the con tin u ou s, o n g o in g nature o f the interaction o f the infant and caregiver. A s suggested earlier, the authors are con cern ed with a m odel that argues that behavior elem ents o f either caregiver or child studied alone are insufficient for understanding what transpires betw een them. L ew is, Brazelton, Stern, and R osen blu m each have directly tried to approach the study o f this interaction. In the reading o f their chapters, it b e com es ob v iou s that, if the often subtly w oven fabric o f interaction is to be understood, w e must think about w h ole new types o f m easurem ent
Rather than con sider on ly the frequency o f single
behaviors show n b y both caregiver and infant, these authors suggest various other techniques w h ich utilize such processes as sequential analyses, conditional probabilities, and sim ultaneous occu rren ces or critical intervention in its on g oin g relationship, to m ention a fe w . O ne overriding im pression is that w e have just begun to con sider these kinds o f m easurem ent and as yet know very little o f their prom ise and lim itation. C learly, the task o f dem arcating what ought to be studied, and how, is still b efore us. W e must not lose sight o f the fact, h ow ever, that m easurem ent problem s are always related to theoretical issues and must be v iew ed as such. O f particular interest in the study o f interaction is the issue o f point o f entry.
M ichael Lewis and Leonard A. Rosenblum
This is a m ost difficult question, fo r if w e do not b elieve in elem ents per se but rather in the continuity o f interaction, then there is no lo g ica l point o f entry. That is, each observed behavior within the dyad is taken to be a fun ction o f the interconnected chain o f behaviors that preceded it in time (or for that matter, it m ay be related to cogn ition s about future events). H ow then can w e k now where to enter this chain o f events? W e can offer no concrete solution but suggest that w e consider context as a potentially important intervening variable in our understanding o f the interaction. B y loo k in g at the beginnings o f the interactive flow in a w ide variety o f circu m scribed contextual settings, such as the play situation (see Stern and B razelton ), or during feedin g or changing, w e m ay better be able to understand the nature o f the chain o f interaction. A t the same time it b ecom es im portant to consider longitudinal studies so that som e questions regarding presum ptive “ first cau ses” m ay be answ ered. If, for exam ple, we are interested in nursing behavior, that is, w h y som e m others nurse their infants and others do not, w ou ld it not be w ise to consider qu estioning the pregnant m other on her nursing view s and then w atching the interaction betw een m other and infant to see h ow the initial step in the m oth er’ s nursing contacts with the infant is set b y a com bination o f her prior attitudes and her actual experience with the infant? W e also m ight lo o k directly at the earliest contacts betw een caregiver and infant. It is interesting that at this time there are few detailed interaction studies con cern in g the first contact betw een a m other (or fa th e r ) and her (or his) infant. In any event these approaches should facilitate m eaningful expansion o f our k n ow led ge. W hether they can actually solve the problem con cern in g point o f entry, h ow ever, is not as certain.
Contributions o f Human Infants to Caregiving and Social Interaction R IC H A R D Q . B E LL National Institute o f M ental Health
There are several indications that w e need a w ay o f thinking about how the young affect parent beh avior. In the last decade there has been increasing a d v oca cy o f greater attention to this area (B e ll, 1971); it has been pointed out that the behavior o f the you n g represents its ow n integrations and patterning, and exerts a very important effect on parents in one p eriod, even if it has developed out o f interactions with parents in a prior period. N ew findings are em erging from a variety o f research strategies w h ich make it possible to isolate child and parent effects (B erberich , 1971; H ilton, 1967; O so fsk y & O C onnell, 1972, S iegel, 1963). W h ile in the past the effect o f the young on parents has even been underestim ated in research literature on other m am m als, Harper (1 9 7 0 ) has now drawn our attention to the fact that the you n g o f many species affect parents to the extent o f determ ining patterns o f utilizing fo o d resources and territory. It has been contended that it is no m ore parsim onious to interpret a correlation found betw een parent and child characteristics at a single point in time as due to the effects o f parents on children, than it is to offer the opposite interpretation (B e ll, 1968). R ecent review s o f research on the effect o f parent practices or techniques (M u ssen , 1970) n ow un iform ly recom m end caution in interpreting correlations betw een parent and child characteristics in a unidirectional fashion, and som e even go further, offerin g substantive interpretations o f the correlations in terms o f the effects o f children on parents. C learly, som e steps toward the d evelopm en t o f a theory o f the effects o f the young on their parents and caregivers is in order, and the present chapter undertakes the first step toward such a theory. T he present chapter is on e-sided in treating only the effects o f the y ou n g , but this is necessary to w ork toward a balance in our perspectives. It is hardly lik ely that another im balance w ill be created, considering that such an occu rren ce
w ou ld
necessitate offsetting over three decades o f socialization
research com m itted alm ost entirely to studying the effects o f parents on their children. This is a review o f the m any w ays in w h ich it appears likely that the effects of 1
R ichard Q. Bell
the you n g m ay be shown in early developm ent, particularly with reference to physical caregiving and social interaction. The chapter is frankly speculative. W h ile interest in this area is rising, there is not sufficient research at present to provide an em pirical basis for a theoretical structure. The conceptual elem ents have been drawn together in m ore o f an expositional than a theoretical structure. The next log ica l step is to introduce general propositions w hich w ill align and organize the elem ents. O nly a start is made in this direction. In drawing together these guidelines toward a theory, it is clearly appreciated that m eaningful and useful application o f the guidelines must be found in the m inute-to-m inute and day-to-day o n g oin g interactions o f parents and children. The concepts are o f value on ly if they draw our attention to aspects o f these interactions that might otherwise be o v erlook ed , or help us focu s on the task o f teasing apart determinants o f these interactions.
CONTRIBUTION OF THE YOUNG TO PARENT LIFE-SUPPORT AND PROTECTION ACTIVITIES For purposes o f discussion the effects o f the you ng are detailed in terms o f tw o very different aspects o f the parent-child interaction. One aspect con cern s the provision o f life support and protection. In this case the parent prim arily behaves so as to avoid undesirable im m ediate or long-range ou tcom es. From the parent standpoint this is an aversive system . At the other extrem e is a kind o f interaction w hich in volves mutual, recip rocal, social interactions. This m ay be referred to as an appetitive system , in that both parent and offspring behave so as to prod u ce or maintain the behavior o f the other. There are m any other kinds o f interactions w hich this chapter does not attempt to treat, since the strategy is to dev elop guidelines out o f a contrast betw een different system s, rather than to provide a com prehensive review o f all kinds o f parent-child exch anges.
Launching Parental Behavior
First, w e present som e speculations on how pregnancy and the neon ate’ s characteristics set in m otion the support and protection activities o f the parent, w hich are subsumed under the term caregivin g for brevity in m ost discussions for the remainder o f the chapter. Harper (1 9 7 2 ) has pointed out that pregnancy itself with its p h y siologica l effects, and the signaling o f a new role for the m other lays the groundw ork for these parental activities, w hich are then set in m otion by the delivery o f the infant. The behavior o f the new born further stimulates parental behavior.
m ovem ents
appearance o f helplessness. The human infant’ s appearance alone cou ld also have som e effect on parental responsiveness in this early period, since the shape o f the head (a short fa ce relative to a large forehead and protruding ch eek s) show s characteristics in line with several other species (T in bergen , 1951). It is
Contributions o f Human Infants
w ell kn ow n in com parative studies that the distinctive appearance o f the you n g produces differential response from
the m em bers o f a co lo n y . B rooks and
H och berg (1 9 6 0 ) have reported data m ore specifically applicable at the human level, n am ely, that variations in line abstractions o f the human infant’ s face are responded to discrim inatively and positively by adults— the concavity o f the fa ce , the height o f the ey es, and other characteristics. Postpartum horm onal effects cou ld be operating at the human level, since we know from R osen blatt’ s (1 9 6 9 ) studies o f rats that maternal behavior is enhanced by a pregnancy termination effect in volvin g horm one changes. It is w ell to keep in mind that the human mother is not static p h y siologically but is maturing p h y sio lo g ica lly in the course o f the process set in m otion by the pregnancy. The arrival o f the infant is also capable o f altering role relationships in the marriage. R yder (1 9 7 3 ) has reported that there is a decline in marital satisfaction reported b y w ives in y ou n g cou ples after having their first baby, in contrast to com parable cou ples without a baby. The decline in marital satisfaction seem s to be due to less attention from the husband. S e n s o r y -M o to r M atching
■ It is evident in cross-fostering animals that the
sensory and m otor system o f the y ou n g is set up so that it matches that o f the parent and not that o f other species. A n amusing exam ple is described by Hersher,
R ich m on d ,
M o o re
(1 9 6 3 ).
cross-fostered , they retained their species-typical tendencies to fo llo w (in the case o f the lam bs), or to leave the m other and lie dow n when sated (in the case o f the kids) during the first few days postpartum . This resulted in the ew es rearing kids b e co m in g highly disturbed, since they were constantly required to leave the flock
w hile the goats rearing lambs were
incessantly “ sh a d o w e d .” It is easy to o v e rlo o k the im portance o f sensory-m otor matching at the human lev el, because there are few opportunities to see the effects o f cross-fostering. A m other rearing a chim panzee infant com m ented on the oppressive effect o f the infant’ s clin g in g (H ayes, 1951). There are other kinds o f data that are suggestive. E isenberg (1 9 7 0 ) reports that human tonal patterns and speechlike signals are rem arkably effective with new borns. Richards (1 9 7 1 ) has remarked on the fact that an en dogen ou s patterning o f neonatal sucking has an effect on the feeding interaction. There are short and lon g intervals betw een the bursts o f sucking. The m other m ov es betw een short bursts, and talks to and smiles at the infant during the lon g intervals betw een bursts.
Launching the Caregiving Bout T o bring the discussion dow n to the level o f actual interaction, it is helpful to think about h ow the infant initiates bouts o f interaction (m eaning in this context sim ply that both mother and infant are interacting fo llo w in g a period during
R ichard Q. Bell
w hich they w ere not). During the first few w eek s, m any bouts are started by the fussing or cryin g o f the infant. The youn g m other is recoverin g from the birth process, and is in m ost cases quite w illing to let the infant sleep and rest as m uch as possible. The cry brings the caregiver to a position where the visual, o lfa cto ry , and tactile stimuli provided by the infant can be effective. Later in the first year, the type o f cry produced by the infant will have com m unication fu n ction s, but it is sufficient at first that it sim ply brings the caregiver into the vicinity.
A s a predictable pattern o f infant behavior d ev elop s, the m oth er’ s response to the early items in a sequence averts a later item. For exam ple, W o lff (1 9 6 6 , p. 86) has described how infants m o v e from qu iescen ce to highly aroused crying. First, a soft w hispering was detected, then gentle m ovem en ts, rhythm ic k ick in g, uncoordinated thrashing, and then fussing or spasm odic crying. If the thrashing is overheard, it m ay provide discrim inative stimuli for maternal behavior w hich averts the rest o f the sequence. A fter the infant can recogn ize and discrim inate the m other, and has dev elop ed som e m inim al time con cep ts, on e other w ay o f starting bouts can be seen. A nticipatory protests occu r when behaviors are show n b y the m other that have been associated in the past with separation. In placing em phasis on the contribution o f the infant’ s cry, I nonetheless recogn ize that its role should not be overestim ated. Bernal (1 9 7 2 ) has reported diary data indicating that few m others respond to what they feel is the nature o f the cry as such during first 10 days o f life. Their k n ow led ge o f h ow lon g it has been since the last feedin g, and h ow adequate the feedin g w as, are important determinants o f their response. In other w ords, the infant’ s cry is im portant, but m others are in no sense puppets on a string, responding without a secon d thought, and cued in on ly b y the cry qualities. In short, it seem s a reasonable prop osition that the pregnan cy, the infant’ s appearance,
the infant’ s behavior all interact with the m oth er’ s role
proscription to create the m other-infant subsystem o f the fam ily. It m ight be w ell to add that these infant characteristics at times on ly interact with the m oth er’ s existence as an adult. She m ay sim ply be trying to maintain her life , without any intention o f socializin g anyone.
Maintaining the Caregiving System Maintaining B eh a v io r within T o ler a n c e Limits o f the Parent
■ H ere again the
cry is used for illustrative purposes, sim ply because w e have so m uch data on infant crying. D uring the first year, a ccordin g to Bell and A insw orth (1 9 7 2 ) the duration o f crying drops from 7 .7 m inutes/hour (range, 21 m inutes/hour to none) in the first 3 m onths, to 4 .4 m inutes/hour in the last 3 m onths. P arm elee’ s (1 9 7 2 ) data indicate a substantial reduction in crying betw een W 2 and 4 m onths. The tolerance o f parents probab ly show s a great.range, but w e do not have any
Contributions o f Human Infants
quantitative data at present. H ow ev er, from three different studies there are indications that parent tolerances are e x ceed ed . O cca sion a lly , crying is so excessive that it reaches the level o f threatening and even breaking dow n the caregivin g
R o b so n
and M oss (1 9 7 0 ) traced changes in subjective
feelin gs o f attachment from retrospective interviews conducted with mothers in the third postnatal m onth. T h ey con clu d ed that attachment decreases in som e mothers
first m onth
if cryin g ,
fussing, and other demands for
p h y sio lo g ica l caregivin g do not decrease as they do in m ost infants. In one case from their study, the m other was enthusiastic during pregnancy, but her positive feelin gs eb bed during the first m onth. Her infant fussed a great deal, was not responsive to h old in g, and was late in exhibiting sm iling and ey e-to-ey e contact. The m other reacted violen tly, wanting nothing to do with the infant. She felt estranged and u n loved. The infant was later found to have suffered relatively serious brain dam age. From the norm ative studies o f crying I have discussed, w e have som e idea that in the first m onth or so there is a period during w hich the mother is in essence at the m ercy o f the crying o f her infant. W hether or not her efforts are the determ ining factor, by the third m onth crying is w ell within what seems to be the tolerance limits o f m ost parents. H o w e v e r, the question o f the effectiveness o f the m other, and o f the b a b y ’ s testing her lim its, is not settled by the third month for all cases, accordin g to B ell and A in sw orth ’ s (1 9 7 2 ) analysis o f sequential relations betw een infant cryin g and maternal ignoring o f crying eqisodes in the four quarters o f the first year. These investigators interpret the correlations betw een quarters as indicating that infants in their sample cried m ore in any given quarter that was preceded by a 3-m onth period during w hich their mothers ignored their cryin g. H ow ev er, there was an increasing tendency, toward the last half o f the year, indicating that the m ore the infant cried in any given quarter, the m ore
in the subsequent quarter.
O f course,
correlational data o f this kind cannot identify causal factors, but if these interpretations are correct, for som e pairs there was evidence o f a breakdow n in the caregivin g system as such, and som ething o f a viciou s cy cle developed. A pparen tly, som e infants exceed ed their m oth er’ s limits. The m other’ s efforts to co p e with the cryin g were inadequate. The infant responded by crying even m ore, and the m other w ithdrew even m ore. G il (1 9 7 0 ) has sum m arized several clin ical and epid em iolog ica l studies o f “ battered ch ild re n .” From the early clin ical studies o f parents w ho battered their children,
it was con clu d ed that the attack on the child was an outlet for
frustrations. Parents, h ow ev er, saw the child as the cause o f the problem . M any o f the parents thought they were being abused by the child. This cou ld readily be dism issed as a parental defense m echanism , except that it is quite typical to find that other children in the fam ily o f an abused child are not abused. This fact raises questions about the stimulus qualities o f the child. Constant fussing,
R ichard Q. Bell
strange and highly irritating cryin g, or other exasperating beh aviors, w ere often reported for the one child subject to abuse in the fam ily . S om e children were abused in successive foster hom es in w hich they w ere placed after the initial abuse. N o other child had been abused previously in these foster hom es. G il’ s survey indicated that deviance in the child was at least as substantial a factor in explaining the incidents as was deviance
in the parent, and the stressful
circum stances under which they lived. O b v iou sly , the stimulus characteristics o f the child do not operate by them selves to induce mistreatment. M ost o f the exam ples I have given in volve testing the upper lim its o f parents. It is less ob viou s that extrem e lethargy in infants can impair the caregivin g relation. At first the you n g mother m ay feel relieved that she has a quiet baby. A fter the first month or tw o, h ow ev er, she m ay b e co m e uneasy. She then stimulates her baby in various w ays.
She seeks the advice o f friends or
professional help if such m easures, carried out over a lon g enough period o f tim e, do not arouse the infant sufficiently. Infants Define Their Own Limits
• In the neonatal period the infant defines what
it will or w ill not incorporate b y sw allow ing or spitting out what is g iven to it. It turns its head away from aversive odors. S om e infants reject solids and fo rce their mothers to return to bottle or breast feedings. Others fall asleep during rigidly scheduled feedin gs, and this e ffectively limits the m oth er’ s behavior. But what about the great volu m e o f caregiving that is not in response to specific stim uli? Here the infant m ay make an unseen contribution. Startles or sustained distress reactions have sufficient im pact on a m other that she is likely thereafter to prevent exposure o f her baby to sudden noises, to too m uch n oise, or to play that goes on overly lon g. If the mother has form ed som e con cep t’ o f fragility and helplessness from the smallness and the thrashing, uncoordinated behavior o f her nev/born, she is quite lik ely to have this con cep t strengthened in later instances b y the infant’ s startles or distress reactions. These reactions inform the parent when sensory and fatigue limits have been ex ceed ed . Readability o f the Infant • There is a possibility that an em pirical approach m ay be opened up to throw light on the problem o f what it is that makes it difficult or easy to take care o f som e infants. K orner, in another chapter in this v olu m e has raised the possibility that the “ readability” o f an infant m ay be a function o f the clarity o f cues to its state. In studies o f observer agreem ent, all o f us w h o have studied very young infants have encountered those w hose states are unclear. M others must have the same problem . This possibility is readily a ccessible to research. Inducing a Singular Caregiving Relationship
■ A sequence o f developm ental
changes in the infant contributes to the m oth er’ s con cep t that she has a singular and essential role to carry out. The sequence starts with discrim ination o f human from inanimate form s, discrim ination o f the m other from others, reactions to
Contributions o f Human Infants
strangers, and, finally, protest at separation. C onsidered as a w h ole, these infant behaviors indicate to the m other that she has been selected for an intense o n e-to-o n e
there w ere no cultural sanctions or role
proscriptions to co n v e y the same m essage. O f course a singular relationship is not always possib le, as in som e institutional settings, and yet caregiving goes on. The point here is that, w here a singular relation is possible, the infant’ s behavior can be counted on to prom ote its em ergen ce.
CO N TR IB U TIO N OF TH E YOUNG TO TH E SOCIAL IN TERACTION SYSTEM In a social interaction system , the responses o f each participant serve as stimuli for the other.
K oh lberg
(1 9 6 9 ) amplifies this definition in the context o f
socialization : “ In general, even sim ple social play and games have the character o f either com plem en tarity, recip rocity, (I do this, then you do that, then I do this), or o f imitation (I do this, you do this to o ). In either case there is a shared pattern o f beh avior, since recip rocal play is a sort o f reciprocal imitation (you fo llo w m e, then I fo llo w y ou ) [p. 4 6 3 ] .” W atson
(1 9 6 6 ) has offered an explanation o f h ow
“ contingency g am es”
in volv in g com plem entarity and reciprocity m ay develop between parent and infant increasingly after the first 3 m onths. A pp lyin g his line o f thinking in the present con text, responses o f the infant that fo llo w qu ickly parent behaviors cou ld by that con tin gen cy acquire reward value, just as those o f the parent could for the infant, leading to a social interchange system in w hich the responses o f each are rewarding for the other— an appetitive system , in contrast to the aversive system in operation relative to provision o f life support and protection. In placin g em phasis on the infant’ s contribution to noncaregiving interactions, I am assum ing, as d o W alters and Parke (1 9 6 5 ), that socialization does not dev elop e x clu siv e ly out o f primary drive reduction. In the same vein, Escalona (1 9 6 8 ) has challenged the classical psychoanalytic form ulation that p s y c h o lo g i cal developm en t occu rs in states o f displeasure incident to delay o f gratification. She feels that developm en t from interaction is best favored by moderate levels o f arousal. H o w e v e r, caregivin g may lead to a state from w hich the infant starts the type o f social interaction in w hich w e expect socialization to be m axim ized. For exam ple, the infant m ay quiet dow n after a diaper has been changed, or sm ile, and thus launch a social interaction.
Initiating the Social Interaction Redu ction action
D em and
■ It is possible
o f early caregiving as the infant show s
R ichard Q. Bell
a decrease in the duration o f cryin g and fussing and an increase in the time it is awake and attentive. Thus the infant provides an increased opportunity for noncaregiving activities to o ccu r. It can be readily understood that a m other is less likely to start a playful interaction with her infant if she is stressed by in consolable cryin g, or by her infant’ s short periods o f sleep that do not co m e at a time permitting her to rest. W hen the caregiving dem and has been reduced by changes that occu r in norm al developm en t, the infant’ s changing con dition can release
pow erfu l
spontaneous play. P ossib ly even b efore, certainly increasingly after
the third m onth, the m oth er’ s effort to reduce unpleasant excitation has reduced sufficiently, and the occa sion s on w h ich positive affective responses have been elicited have increased, to an extent that w e cou ld say that the social interaction system is w ell on its w ay. Manipulability o f States in the Infant
• The ability o f infants to show alterations
in state in response to the efforts o f parents is a m ore active contribution to the initiation o f the social interaction system than the conditions just m entioned. E scalona (1 9 6 8 ) has described h ow a mother stimulates a drow sy infant to bring it back to a state in w hich they can interact. Then the m other m ay have to calm the infant dow n and soothe it as it b e co m es too agitated. D uring visual attention the mother adjusts the level o f stimulation to the infant’ s interest and arousal. The infant behavior that supports these parental efforts is state m anipulability. Bridger and Birns (1 9 6 3 ) have reported quantitative data indicating that infants vary greatly in response to identical efforts to manipulate states. A pproxim ately 18% o f infants have what is termed “ c o l i c ,” a con d ition in w hich there is nearly a com plete breakdow n in state m anipulability. C o lic m axim izes caregiving interactions and m inim izes social interactions. Turning to con dition s still farther from the normal range, Brazelton (1 9 6 2 ) has described in detail a case in w hich an infant’ s inflexibility o f states, as w ell as lim ited range, had a severe effect on the m other. ’ R esp on sive B eh a v ior
• The m ere fact that an infant does som ething, literally
anything other than fussing or cryin g , as a response to a m oth er’ s stim ulation, is another and
interaction. A mass m ovem ent or a babble are responses, and again the m other learns that what she does matters. W atson (1 9 6 6 ) was im pressed with the excitem ent he saw d evelopin g in his infant as a response to con tin gen cy gam es.
Initiating Social Interactions at the Level of Bouts Jones and M oss in our laboratory (1 9 7 1 ) have reported that infants in the aw ake-active state tend to babble m uch m ore when they are by them selves than when the m other is present. The m other w ho hears these episod es o f noncrying
Contributions o f Human Infants
voca liza tion s, even though bu sy, often cannot resist the appeal, and com es to the infant to enter into the gam e. The infant’ s babbling thus m ay co m e to serve as a discrim inative stimulus for a reciprocal “ g a m e .” In such instances the infant often discontinues the babbling and shifts into a reciprocal relation in w hich the m other v o ca lize s or tou ch es, and the infant responds b y sm iling and v ocalizin g. O ften , a sitting infant gurgles and sm iles w hen a mother passes on her w ay to d o a hou seh old ch o re , thus inveigling her into interaction. O ne o f the infants in our studies cou ld em it a special n oncrying vocalization w hich was quite effective in bringing the m other in from the kitchen to start an interaction. O ne other w ay in w h ich bouts o f interaction are started during these early months is by the infant rem aining quiet for a longer time than the m other w ould ordinarily expect, after aw akening. The infant m ay sim ply be quiet and attentive, and not even m ov in g . This brings the m other, and the interaction bout ensues.
Maintaining the Social Interaction System The R o l e o f A ttach m ent ■ B oth the difficulties and the advantages o f attempting a distinction
are illustrated by
application o f B o w lb y ’ s (1 9 6 9 ) theory o f attachment in the present context. The signal
infant’ s repertoire
(cryin g ,
v oca liza tio n ) and the execu tive aspects o f behavior (clin g in g , approach, and fo llo w in g ) create and maintain the proxim ity that is essential to caregivin g. A ls o , w ithout p rox im ity , one cannot have a socia l interaction system . The shortcom ing o f the theory o f attachment that B o w lb y has developed is that it does not speak sufficiently to the socia l interaction that is the key to socialization. Proxim ity is necessary but not sufficient. S m ilin g and vocalization are not on ly signals for prom oting and maintaining attachment but are also responses that maintain mothers in the social interaction. In that they are partial equivalents o f what the mother herself is d oin g, they are precursors o f what w ill prove to be very engaging for the mother in later d ev elop m en t— observational learning. The you n g child reproduces parts o f what the m odel is d o in g , and then puts the com ponents together in fascinating new com bin ation s. T he you n g are able to play with these com pon en ts, as Bruner (1 9 7 2 ) has pointed out. The m other can be maintained in the social interaction by w atching this play, as w e ll as b y being played with. Bruner (1 9 7 2 ) also adds that a special quality in the responsiveness o f the y ou n g is a positive reaction to n ovelty w hen in a secure setting. This facilitates the m oth er’ s play. She can try very ridiculous things and is often rewarded with a laugh or sm ile. If w e fo llo w C airns’ (1 9 6 7 ) p osition , behavior that has saliency (and the infant’ s beh avior certainly seem s to have saliency for parents) can maintain socia l interaction system s. G ew irtz (1 9 6 1 ) has made room in his theories for the
R ichard Q. Bell
possibility that maternal behaviors may be unlearned reinforcers. B y the same token, som e infant behaviors cou ld reinforcers for maternal behavior.
Successive Production o f N o v e l R e s p o n se s
• Each o f the infant’ s responses
m ay have an inherent value in triggering specific parental behavior. Cutting across all this specificity is the feature o f n ovelty. The infant continually show s new behaviors w hich excite and interest the parent, as G ew irtz (1 9 6 1 ) pointed out lon g ago. If the m other is attentive to the infant during the first 3 w eek s,'sh e m ay notice a strange little sm ile appearing in som e phases o f sleep and she may see that som e noises she makes w hile the infant is asleep p rod u ce this sm ile. Later this sm ile appears w hen the infant is op en -ey ed , im m ediately after a feedin g period. T ow ard the end o f the third w eek , the sm ile m ay appear in response to her v o ice m ore than to the other sounds. D uring this same 3 -w eek p eriod, she sees changes in attentive behavior. She sees that the infant quiets and looks bright-eyed when attending. She sees an increase in general activity and thrashing about in con n ection with attentive behavior. In the fourth and fifth w eeks she is treated to a continuing k a leid oscop e o f n ovelty. She is suddenly aware that her baby focu ses on her fa ce , that they have ey e-to -e y e contact, that her face is beginning to register m ore than som e other stimuli, and that som e sm iles appear when she m oves her head. B etw een the fifth and seventh w eeks, she sees few er m outh and head m ovem ents, sees m uch m ore sm iling, and is delighted to hear soft co o in g vocalizations a ccom p an yin g the infant’ s periods o f attention. The rapid succession o f these novel behaviors makes m ore than a contribution to attachment. The novelty cou ld very w ell contribute to the positive quality o f the interaction and thus play a role in m aintaining a social system . Changes during the first fe w w eeks have been described in detail. It is easy to im agine the im pact o f m any other changes m anifested by the infant, such as the beginning
indiscrim inate reaching with reaching toward the m ost salient o b je c t, sitting up, inhibition o f reaching toward unfam iliar ob jects, craw ling, and then standing’ The toddler finally m oves beyon d a “ stilt” w alk, and then begins to em it w ords. The early presch ooler utters sentences. A gain w e need not be con cern ed in the present context about the earliest origins o f these behaviors. The important point is that at certain points in time n ew
and these have an im pact, how ever maturational
processes m ay interact with the m other’ s caregiving and stim ulation. The average mother cannot help but be affected by these changes. The m other w ho essentially maintains a caregiving system m ay not k now m uch about the infant and what has been show n during the last w eek or so, when one asks her to report’ The m other w ho functions both as a caregiver and as a partner in social
Contributions o f Human Infants
interaction is likely to be m ore aware o f the novel behaviors show ing up in each period. B ehaviors Showing D evelopm ental P rog ress
• That novelty itself is not enough
can be clearly seen in the fact that periods o f reorganization and regression in y ou n g children are very disturbing to parents. T o understand w hy tem porary setbacks are upsetting to parents, it is w ell to keep in mind that m ost o f the novel changes that have been m entioned above are changes in the direction o f increasingly adultlike behavior. There are oddities along the w ay, but generally the infant or y ou n g child continually m oves in the general direction o f being m ore like the adult and less like the strange and enigm atic physiological being with w h om the parents w ere first con fron ted in the neonatal period. B ehaviors
Sh ow in g Modifiability
• It seem s likely that the k aleid oscop ic
m ovem en t toward m ore and m ore adultlike behaviors w ould in itself have a con siderable supportive fu n ction , even if there w ere no indication that the infant’ s beh avior is responsive to maternal behavior. H ow ever, it is clear that the infant has som e basic w ays o f telling the m other that what she does matters. It has been m entioned earlier that responsiveness itself has a supportive role to play in the interaction. Then there is the next level o f m odifiability— learning. T o achieve a satisfactory criterion o f con dition in g, Papousek (1967 a, b) found it necessary to use 177 trials when con dition in g was started within the new born period , but used on ly 42 when starting in the third month and 28 when starting in the fifth m onth. Thus if a m other behaved in such a w ay as to incorporate the basic elem ents o f P apousek ’ s procedure, she might feel b y the fourth month that she cou ld
have som e effect on the infant beyond mere responsiveness or
distraction. If the mother persisted as lon g as scientists w h o have conditioned social
(B rack bill,
R h ein gold ,
G ew irtz,
W e isb e rg , 1963), she might see that the infant’ s sm iling or vocalization was com in g under her con trol. In the m onths and early years to fo llo w , she w ould see observational learning in m otor beh avior, and then reproduction o f partial speech form s. F inally, she w ou ld see a stage w hen her ow n verbal description o f con sequ en ces cou ld alter a c h ild ’ s behavior so that a trial and error process was not necessary for the ch ild. A ll in all, under this heading the infant’ s contribution to m aintaining the social interaction lies in the fact that responsiveness and m odifiability are show n. A ltering the Basis f o r Social Interaction
• B irch and L efford (1 9 6 7 , p. 110)
have described the shift from response to tactile stimuli to visual stimuli in the first year. Studies o f ev ok ed potential on both human infants and low er animals (E llin g son , 1964) have show n that cortical response to tactile stimuli is relatively mature in earliest in fan cy, whereas response to auditory and visual stimuli b ecom e s mature in form som etim e later. D uring this same developm ental period,
Richard Q. Bell
several investigators w h o attended prim arily to the nature o f the m other-infant interaction (L ew is & Ban, 1971; Lusk & L ew is, 1972; M o ss , 1967) noted a proxim al-distal shift in infant beh aviors, and recorded differences in maternal behavior that paralleled this shift. For both sexes, touching, a proxim al behavior, decreases over age, and look in g , the m ost distal beh avior, increases. There are som e sex differences w hich m ake this m ore com p licated , but fo r the present purpose it is enough to note that the proxim al-distal shift, w hatever the origins, changes the basis for the social interaction process. In a sense the change in the infant’ s behavior places the relationship m ore on an adult basis. Interactions can o ccu r at clo se range as w ell as at a distance. The young ch ild ’ s behavior often makes a contribution to som e further changes in developm ent. T o quote M a c c o b y and M asters (1 9 7 0 ): The scraps o f inform ation that w e do have point to a decline in proxim ity seeking, with attention seeking and approval seeking maintained at a constant level or increasing. There appears to be a shift in target from the m other and other adults to age-m ates. W ith respect to these changes one is struck by the parallel with human prim ates, in w h om infant play and other social contacts with age-m ates take m ore and m ore o f the infant’ s tim e, w hile occa sion s w here the infant flees to the m other for com fort and protection decline in freq u en cy , and the amount o f time sim ply spent staying near the m other becom es progressively less [p. 1 4 5 ].”
Terminating Social Interaction Bouts The supine and sitting infant can terminate a bout by fussing, b e co m in g irritable, and turning its head aw ay, or by sim ply falling asleep. In P ap ousek ’ s studies (1 9 6 7 a ,b )
con dition in g procedure b efore the third month often show ed distress. This distress was sufficiently effective to even terminate an experim ental procedure (let alone a m other-infant interaction).- The craw ling infant can show any o f the termination behaviors o f the you n ger infants, as w ell as craw ling aw ay from the parent. The toddler and presch ooler can also show any o f the preced in g but, in addition, has interactions.
GENERAL PRINCIPLES E m ergent Child B eh a v ior
• It is necessary to realize that each period o f
interaction is capable o f altering the status o f a ch ild , so that during the subsequent period o f interaction the child stimulates the parent in a different fash ion , or reacts differently to parent behavior. This principle m ay be operative in the findings o f Hartup (1 9 5 8 ) and Baer (1 9 6 2 ) that w ithholding positive
Contributions o f Human Infants
reinforcem ent on ly increased depen den cy in children w ho were already highly dependent. W hatever conditions led to high dependency prior to the ch ild ’ s participation in the study altered the responsivity o f the child to withdrawal o f positive reinforcem ent. T o pursue the im plications o f this principle, we should study parent-child interactions during one p eriod, assess child behavior at som e point w hen it appears stable toward the end o f this phase, and then, during the next p eriod , assess the effects on the parent o f the ch ild ’ s w ay o f functioning. I have not fou n d any exam ples o f research that have done this. H om eosta tic M o d e l
• One very general principle about the behavior o f the
you n g is that they contribute too m uch or too little in the w ay o f som e behaviors, or show som e behaviors too early or too late in terms o f parent expectations (B e ll, 1971). B riefly, it is assumed that each participant in a social or caregiving interaction has upper and low er limits relative to the intensity, frequ en cy, or situational appropriateness o f behavior show n by the other. W hen the upper limit for one participant is reached, that participant is likely to react in such a w ay as to redirect or reduce the excessive or inappropriate behavior (upper-lim it control reaction). W hen the low er lim it is reached, the reaction is to stimulate, prim e, or in other w ays to increase the insufficient or nonexistent behavior (low er-lim it control reaction). This hom eostatic con cept needs im plem enting propositions before it can lead to testable hypotheses. H ow ev er, it has proved helpful in thinking about findings that have already been un covered. For exam ple, one o f B eck w ith ’ s (1971) findings, from an observational study o f mother-infant interaction in 7-m onth-old adopted infants, b e com es m eaningful w hen looked at from the hom eostatic standpoint. Verbal discouragem ent was correlated .49 with infant Gesell scores, the on ly significant correlation found betw een measures o f maternal speech and the G esell. The explanation offered was that infants show ing m ore locom otion and reaching out fo r ob je cts, and thus scorin g high on the G esell, were m ore difficult to m anage in a prop erty-con sciou s hom e. Verbal discouragem ent was presum ably one o f the m other’ s upper-lim it control techniques. M a c c o b y and Masters (1 9 7 0 ) have used a hom eostatic con cept in explaining data from E m m erich ’ s (1 9 6 4 ) longitudinal study in w hich it was found that an interesting developm ental transformation occurred over a 2-year time in the p resch ool period. Previously interpersonally negative children becam e p oised , w hile their previou sly interpersonally positive counterparts m anifested social insecurity. The explanation offered b y M a c c o b y and Masters (1 9 7 0 ) was “ Perhaps in anticipation o f the ch ild ’ s entry into the m ore form al kindergarten setting, socia lizin g agents at this time w ere putting pressure on the outgoin g child to m odulate his aggressiveness, w hile a sim ultaneous attempt is being m ade to influence a self-con tain ed child to b e co m e m ore ou tgoin g [p. 9 9 ] .”
R ichard Q. Bell
The N ature o f Control
• It is evident that one o f the individuals in the
parent-child socialization system is m uch m ore mature than the other, and m ore clo se ly approxim ates the adult patterns o f the culture. This feature o f course led to the first oversim plification o f socialization research, nam ely, the m odel o f an agent
acting u pon
a m alleable
counteracting this earlier sim plification in the history o f our research, it is easy to b e co m e attracted to another sim plification, that the infant and y ou n g child socia lize the parents. The controls in volved are far too com plicated to m ake it likely that this other oversim plification w ill lead to any better understanding o f the interaction system . First o f all, what are the im plications o f the inequality o f maturity for control exerted by the infant or child on the parent? The inequality does not p reclu de the existence o f a reciprocal relation. A s Skinner (1 9 7 1 ) has pointed out, there is even a reciprocal relation betw een the physicist and the subatom ic particles w h ose behavior the experim ent is designed to control. The experim en ter’ s behavior is shaped and controlled b y the nature o f the particles. It should also be considered that an individual w h o starts an interaction by that very fact is exercisin g control o v er the other. The other has to react on the initiator’ s behavioral “ hom e g r o u n d ,” so to speak. Thus, when w e realize that an infant or you n g child starts approxim ately 5 0 % o f the interactions (B ell 1971), we must con sider that a substantial degree o f control is exerted thereby over the parent, even if it is not exerted in any other w ay. In this respect there is a type o f balance in the relationship, w hich fits neither the notion o f the parents socializin g the you n g in a unidirectional fash ion , or the op p osite, that the you n g socialize adults so that they b e co m e parents. There is also a type o f balance in control due to the fact that the infant selectively reinforces parent beh avior, thus m od ify in g socialization efforts. A ls o , the fact that the infant or y ou n g child is m ore com petent in one sense than the you n g, inexperienced parent, offsets the greater maturity o f parent. T h e neonate is very com petent in bringing the parent to the general area, and in p rod u cin g desired behavior. It has a set o f behaviors w hich are highly effective in bringing about support, protection, and m aintenance o f optim al states. In other w ords com peten ce in con trollin g the beh avior o f another so as to prod u ce a certain ou tcom e is different from maturity, w h ich is the stage o f m ovem en t toward adult form s o f behavior in a culture. A t first, Skinner (1 9 7 1 ) notes that the infant controls the parent without a justing its ow n behavior to achieve certain con sequ en ces. Initially parent s behavior is intentional.
on ly the
The parent acts so as to ach ieve certain
con sequ en ces. (In m any instances, h ow ev er, as I have m entioned, the parent is sim ply fu nctioning as an adult). Parents in the socialization role are presum ably guided by the norms and values o f the culture in w hich they w ere reared including the subculture defined by their ow n fam ilies. Even though there is
Contributions o f Human Infants
increasing ev id en ce o f intentional behavior in the child by the secon d year o f life, it is ob v io u s that the intentional behavior o f the parent covers a m uch longer span o f time and in volves m uch m ore general o b jectiv es. In sum m ary, then, the parent-child system is a reciprocal relation involving tw o
in maturity although not in
co m p ete n ce , in terms o f ability to affect each other. The relationship involves m uch m ore and longer-range intention on the part o f one participant than on the part o f the other. There is a certain balance o f controls, in that the greater intentional beh avior o f the parent is offset by tw o features o f the offsp rin g ’ s behavior:
(1 ) the active short-range initiation o f interactions, and (2) the
organization o f the behavior so that it is com p ellin g and selectively reinforcing. M u ch o f the m odification o f child behavior toward cultural norms occurs in the con text o f parental adjustments and accom m odation s to the initiations o f the y ou n g.
Summary P regnancy, the infant’ s physical appearance, the helpless thrashing m ovem ents, as w ell as the fact that the infant’ s sensory and m otor system matches that o f the m other, all contribute to launching ca regivin g, defined as the provision o f life support and protection. A s the behavior o f the infant becom es increasingly org an ized , early items in a sequence b e co m e discrim inative stimuli for maternal avoid an ce undesirable
b eh avior, and
unpleasant ou tcom es
(an aversive system ). C aregiving is
maintained in part because infants provide interpretable cues to their conditions, define their ow n sensory and fatigue lim its, and maintain their protest behavior within the limits o f a ca regiver’ s tolerance. Their progressively discrim inating attention to the caregiver, and their proxim ity-m aintaining behaviors, tend to induce a singular, on e -to -o n e relationship with the caregiver, where this is possib le. , Socia l interactions betw een the young and the parents in volve the reciprocal exch an ge o f behaviors with positive value, so that the contribution o f the young lies not in providin g signals to parents o f aversive consequences that may d ev elo p . Infant behavior in this case generates appetitive parental behavior. The you n g contribute to socia l interactions by reducing the dem and for caregiving (by bein g
ex ch a n g e),
m anipulations o f states, b y bein g responsive in a very general sense, and by actively initiating socia l interactions. A lth ou gh the signal and execu tive behaviors o f the you n g that maintain proxim ity are important to both caregivin g and social interaction, they are not sufficient to maintain the latter. The infant’ s responses that have positive values fo r the parent, rather than those that are cues to avoid unpleasant ou tcom es, are
R ichard Q. Bell
the contribution o f the you n g to social interaction. E xam ples are sm iling and vocalization , partial reproduction o f adult behaviors, playing at com binations and recom binations o f these partials, su ccessive and k a leid oscop ic prod u ction o f n ovel responses, show ing developm ental progress, and general m odifiability o f behavior. W hile playing their part in maintaining social interaction, the young also alter its basis, as seen in the shift from response to proxim al versus distal stimuli in the first year. Increasing activity, and behaviors directed to the production o f variety in stim ulation, also alter the basis fo r social interaction. Peers can provide m ore activity and variety in stimulation than parents, as the y ou n g ch ild ’ s m otor and com m u n ication capabilities m ake peer interaction possible. Three
contributions made by the you n g. In both caregiving and social interaction, the y ou n g change the general status o f their behavior in one period o f d evelopm en t, so that their effects on parents in a subsequent period are different. R esearch strategies are needed that can detect these changing effects o f em ergent behavior. T he origins o f the em ergent behavior are no m ore important than the changing effects. A nother very general principle is that the behavior o f the you n g falls betw een the extrem es o f quantitative excess or d eficien cy , or inappropriate tim ing relative to parent expectations. E xcessive or premature behavior induces what is termed upper-lim it parent controls that are intended to redirect or reduce behavior. L ow er-lim it parent controls occu r in response to insufficient or delayed onset o f behavior in the y ou n g. Extensions o f this hom eostatic m odel have proved helpful in explaining findings in the literature on socialization . Finally, reflection on the nature o f controls exerted over parent behavior b y the you n g leads to the thought that there m ay be a balance in controls due to the fact that the greater maturity and long-term intentional behavior o f parents is offset b y the sheer volu m e o f interactions started b y the y ou n g , b y the com p ellin g nature o f these behaviors, and by the w ay they selectively reinforce parental behavior.
References Baer, D. M . A technique o f social rein forcem en t fo r the study o f ch ild b e h a v io r B ehavior av oid in g 847—858.
rein forcem ent
w ithdraw al.
Child D e v e lo p m en t,
I k c k ™ t!\’ L ' Relati°n sh ip s betw een attributes o f m others and their in fan ts’ 1 .0 Child D ev elo p m en t, 1 9 7 1 ,4 2 , 1 0 8 3 -1 0 9 7 . M
’ R - ,Q ; A rf nterPretation o f the direction o f effects in studies o f socia liza tion P sy ch o lo g ica l R ev iew , 1968, 7 5 , 8 1 -9 5 . '
c a r e ,a k e r
b e h a v io r
o f f s p r in 8 '
D e K ,°^ memai
Contributions o f Human Infants
Bell, S. M , & Ainsworth, M . D. Infant cryin g and maternal responsiveness. Child D ev elo p m en t, 1 9 7 2 ,4 3 , 1 1 7 1 -1 1 9 0 .
Bernal, J. C ryin g during the first ten days o f life , and maternal responses. D ev elop m en ta l M e d ic in e and Child N e u r o lo g y , 1972, 14, 3 6 2 -3 7 2 . Berberich, J. P. D o the c h ild ’ s responses shape the teaching beh avior o f adults? Journal o f E xperim en ta l R e se a r c h in P erson ality, 1971, 5 , 9 2 -9 7 .
Birch, H . E ., & Lefford, A. V isual differentiation, intersensory integration, and voluntary
M o n o g ra p h s
o f the S o ciety fo r
R esea rch
D ev elo p m en t, 1967, 3 2 (2 , Serial N o . 110). B o w lb y , J . A tta ch m en t and loss. V o l. 1. N ew Y o r k : B asic B o o k s , 1969.
Brackbill, Y . E xtinction o f the sm iling response in infants as a fu n ction o f reinforcem ent sch ed u le. Child D ev elo p m en t, 1 9 5 8 ,2 9 , 1 1 5 -1 2 4 .
Brazelton, T . O bservations o f the neonate. Journal o f the A m erica n A ca d em y o f Child P sych ia try, 1962, 1, 3 8 -5 8 .
Bridger, W ., & Birns, B. N eon ates’ b eh avior and au ton om ic responses to stress during sooth in g . R ec e n t A d v a n ces in B io lo g ic a l P sych ia try, 1963, 5 , 1 -6 .
Brooks, V . , & H ochberg, J. A p sych op h ysica l study o f “ cu te n e ss.” P ercep tu a l and M o to r Skills, 1 9 6 0 , 11, 2 05.
Bruner, J . S. Nature and uses of im m aturity. A m erica n P sych olog ist, 1972, 27, 6 8 7 -7 0 8 .
Cairns, R . B. T he attachment b eh avior o f m am m als. P sy ch o lo g ica l R ev iew , 1967, 73, 4 0 6 -4 2 6 .
Eisenberg, R . B. T he d ev elop m en t o f hearing in m an: A n assessm ent o f current status. A s h a , 1 9 7 0 , 12 (3 ), 1 1 9 -1 2 3 . Ellingson, R . J. C erebral electrical responses to auditory and visual stimuli in the infant (hum an and subhum an studies). In P. K ella w a y and I. Petersen (E d s .), N eu ro lo g ica l and e le c tro en cep h a lo g ra p h ic co rrela tiv e studies in infancy. N ew Y o rk : G rune and Stratton, 1964. Pp. 7 8 -1 1 6 .
Em m erich, W . C ontinuity and stability in early social d evelop m en t. Child D ev elo p m en t, 1 9 6 4 ,3 5 ,3 1 1 - 3 3 2 .
Escalona, S. T he roots o f individuality. C h ica g o : A ld in e , 1968. Gewirtz, J . L. A learning analysis o f the effects o f normal stim ulation, privation and deprivation o n the acquisition o f social m otivation and attachment. In B . M . Foss ( E d .), D eterm in an ts o f infant beh a vior. N ew Y o rk : W ile y , 1961. Pp. 2 1 3 -2 9 0 .
G il, D. G . V io le n c e against ch ild ren . C a m b rid g e, M a ss.: Harvard U niversity Press, 1970.
O n togen etic
p h y log en etic
relationship in m am m als. A d v a n ces in the Study o f B eh a v io r, 1970, 3 , 7 5 -1 1 7 .
H arper, L . V . E ffects o f the parent-offspring relationship upon the parent. U npublished m anuscript,
C a liforn ia , D avis.
Departm ent o f A p p lie d
B ehavioral S cie n ce s, U niversity o f
R ichard Q. Bell
Hartup, W . W . Nurturance and nurturance-withdraw al in relation to the d ep en d en cy beh avior o f p resch ool children. Child Development, 1 9 5 8 ,2 9 , 1 9 1 -2 0 1 . Hayes, C. The ape in our house. N ew Y o rk : Harper, 1951. Hersher, L ., Richm ond, J. B ., & M oore, A . U . M od ifiability o f the critical period fo r the d evelopm en t o f maternal b eh avior in sheep and goats. Behaviour, L e id e n , 1963, 2 0 , 3 1 1 -3 2 0 . Hilton, I. D ifferen ces in the beh avior o f m others tow ard first- and later-born children. Journal of Personality and Social Psychology, 1967, 7 (3 ), 2 8 2 -2 9 0 . Jones, S. J., & M oss, H. A. A g e , state, and maternal b eh avior associated with infant vocalization s. Child Development, 1971, 4 2 , 1 0 3 9 -1 0 5 1 . Kohlberg,
seq u en ce:
cog n itiv e-d ev elop m en ta l
socialization . In D . A . G oslin (E d .), Handbook of socialization theory and research. C h ica g o: Rand M cN a lly , 1969. P p. 347 ^ 1 8 0 .
Lewis, M ., & Ban, P. Stability o f attachment beh avior: A transform ational analysis. Paper presented at the m eeting o f the S ociety fo r R esearch in C hild D e v e lo p m e n t, M in n eap olis, M in n esota, 1971.
Lusk, D ., & Lewis, M . M other-infant interaction and infant d ev elop m en t a m on g the W o lo f o f Senegal. Human Development, 1972, 15, 5 8 -6 9 . M accoby, E ., & Masters, J. C . Attachm ent and d ep en d en cy . In P. H. M u ssen (E d .), Carmichael’s manual of child psychology. (3rd e d .) N ew Y o rk : W ile y , 1970. Pp 7 3 -1 5 8 .
M oss, H. A. S ex , a ge, and state as determinants o f m other-infant interaction. Merrill-Palmer Quarterly, 1967, 13, 1 9 -3 6 . Mussen, P. H. (E d.) Carmichael’s manual of child psychology. (3rd e d .) N ew Y o rk W ile y , 1970.
Osofsky, J. D ., & O ’ Connell, E. J. Parent-child interaction: D aughters’ effects upon m others’ and fathers’ beh aviors. Developmental Psychology, 1972, 7, 1 5 7 -1 6 8 . Papousek, H. Experim ental studies o f appetitional beh avior in human n ew b orn s and infants. In H . W . S teven son , E. H. H ess, & H. L . R h ein g old (E d s .), Early behavior: Comparative and developmental approaches. N ew Y o rk : W ile y , 1967. (a) Papousek, H. C ondition in g during early postnatal develop m en t. In Y . B rackbill & G . G . T h om p son (E d s .), Behavior in infancy and early childhood. N ew Y o r k ' Free Press 1967, Pp. 2 5 9 -2 7 4 . (b )
Parmelee, A . H. Jr. D evelop m en t o f states in infants. In C . C lem en te, D . Purpura, & F. M ayer (E d s .), Maturation of brain mechanisms related to sleep behavior. N ew Y o rk : A ca d e m ic Press, 1972, Pp. 1 9 9 -2 2 8 .
Rheingold, H. L ., Gewirtz, J. L ., & Ross, H. W . S ocial con d ition in g o f voca liza tion s in the infant. Journal of Comparative and Physiological Psychology 1959 52 6 8 -7 3 .
Richards, M . P. S ocial interaction in the first w eek s o f human life . Psychiatria, Neurologia, Neurochirurgia, 1971, 7 4 , 3 5 -4 2 . ’
Contributions o f Human Infants
R obson , K . S. & M oss, H . A . Patterns and determinants o f maternal attachment. Journal of Pediatrics, 1970, 77, 9 7 6 -9 8 5 . Rosenblatt, J. S. The d ev elop m en t o f maternal responsiveness in the rat. American Journal of Orthopsychiatry, 1969, 39, 3 6 -5 6 . R yder, R . G . T he relationship betw een h avin g a child and changes in reported “ marriage sa tisfa ctio n .” Journal of Marriage and the Family, 1973, in press. Siegel, G . M . A dult verbal beh avior with retarded children labeled as “ h ig h ” or “ lo w ” in verbal ability. American Journal of Mental Deficiency, 1963, 68 (3 ), 4 1 7 -4 2 4 . Skinner, B. F. Beyond freedom and dignity. N ew Y o r k : K n o p f, 1971. Tinbergen, N . The study of instinct. L on d on : O x fo r d , 1951. W alters, R . H ., & Parke, R . D. The role of the distance receptors in the development of social responsiveness. In L. P. Lipsitt and C . C . Spiker (E d s.), Advances in Child Development and Behavior, V o l. 2. N ew Y o r k : A ca d e m ic Press, 1965. P p. 5 9 -9 6 . W atson, J. S. T he d ev elop m en t and generalization o f “ con tin g en cy aw areness” in early in fa n cy : S om e h yp oth eses. Merrill-Palmer Quarterly of Behavior and Development, 19 66, 12, 1 2 3 -1 3 5 .
S ocia l
n on socia l
con d ition in g
voca liza tion s.
Development, 1963, 34, 3 7 7 -3 8 8 . W olff, P. H . The causes, controls, and organization of behavior in the neonate. N ew Y o rk : International U niversities Press, 1966.
An Interactional Approach to the Mother-Infant Dyad1 M IC H A E L L E W IS an d S U SA N L E E -P A IN T E R Educational Testing Service
P s y c h o lo g y , o f all the scien ces, m ay be the m ost interactive; the study o f elem ents per se the least fruitful. S low ly the m odels for studying human behavior have begun to reflect this. M od els fo r the acquisition o f k n ow led ge (Piaget being the
the developm ent o f
relationships (fo r exam ple, L ew is, 1972) reflect the realization that only through interaction can w e study, without distortion, human behavior. This interactionalist point o f view is in general still foreign to p sy ch olog y and is resisted. This is due prim arily to the prevailing reductionalist philosoph y. That this is the case is rather strange. W h ile the study o f physics has surrendered its reliance upon the nineteenth century m odel o f scien ce, p s y ch o lo g y still clings to this view . In this chapter w e take a rather extrem e interactionalist position in order to present a strong counterposition to the prevailing v iew . W e begin our discussion with various m odels o f the caregiver-in fan t2 relationship. In this regard it is important to note that the nature o f the m odel o f the caregiver-infant relationship is often im plicitly given in the observation and measurement techniques o f the study. A lth ou gh the researcher m ay claim to have no underlying m odel o f the relationship, his observation and m easurem ent procedures belie this fact. A fter presentation o f the m od els, w e discuss the measurement procedures that form a part o f the m odels. T o do this w e take data obtained in an em pirical study. Finally, w e con sider the interactionalist approach to the environm ent-organism dyad.
M O D E L S O F IN T E R A C T IO N The first m o d e l, and that m ost w idely held today, might be aptly called the elem ent m odel (see Figure 1). In this m odel there are two elem ents, and one 'T his research was supported by the Spencer Foundation. 2W e prefer the term caregiver rather than caretaker since we interpret the adult as giving care rather than taking the cares o f the infant away. Note that even our language reflects the interactive nature o f the relationship. 21
M ichael Lewis and Susan Lee-Painter
f ig u r e
1, Sim ple elem ent m odel indicating relatively little interaction.
sim ply asks what one o f these elem ents does. In m ost cases w e study what the m other does— the thicker arrow reflects this. For our consideration one o f the elem ents is the infant, the other the environm ent. M ore sp ecifically , the infant elem ent is a set o f infant behaviors w hich vary as a function o f age o f the child. The environm ental elem ent can either be things, such as toys (adult-defined) or ob jects. A lternatively, it cou ld be p eop le. The arrows in this m odel represent the direction o f study. This m odel reflects studies that ask the basic question h ow m uch o f what kind o f behavior occu rs. If w e ask it o f the infant, w e ask specifically, for exam ple, h ow m uch sm iling or vocalization does an infant produ ce in an hour or tw o o f observation. For the environm ent w e usually refer to p eop le. In som e sense this reveals the illog ic o f this m od el. N o one is interested in h ow m any times the cradle rocks in 2 hours, for w e realize, although w e never state ex p licitly, that the study o f that elem ent in the m odel m akes little sense unless w e study it in interaction with another elem ent, nam ely, the infant. Thus on the environm ent side w e study on ly p eop le. The question w e usually ask, for exam ple, is, H o w m uch does the mother talk to or look at the infant? This m odel im plicitly can b e co m e interactive when w e start to lo o k at either individual differences or developm ental con sequ en ces. W hen w e begin to ask about differences betw een the sexes or am ong social classes in terms o f either the infant’ s or caregiver’ s behavior, w e m ay be im plying that the m iddle-class infant does som ething m ore than the w ork in g-class infant because the caregiver does som ething different. Interestingly, caregiver considered to be caused by infant differences.
W e recogn ize that instead o f an interactional approach som e investigators prefer to talk about basic b io lo g ica l differences. Thus one infant cries m ore or less than another not because o f any interaction, but because o f som e “ b a s ic” b io lo g ica l difference betw een them. A g a in , h ow ev er, caregiver differences are not
a b io lo g ica l
differences not considered a function o f an interaction are asym m etrical with respect to the m od el, b io lo g ica lly caused for the infant, learning caused for the caregiver. O n ly the interactional position is sym m etrica] to both elem ents. B esides individual differences there are developm ental differen ces. In this m o d e l, seen in Figure 2 , w e observe what is usually studied. In this case there is infant behavior at times II and 12 and environm ental behavior at times E l and E l. In this m odel there is also asym m etry. W hat is usually studied here is the careg iv er’ s behavior at time E l and the infant’ s behavior at time 12, for exam ple,
Interactional A pp roach to the M other-Infant Dyad
FIGURE 2. E lem ent m od el used to d escribe the relationship o f present to subsequent beh avior.
the am ount o f the m other’ s vocalization when the child is 3 months old ( E l ) and the infant’ s language ability at 2 years (12). This use o f the m odel by correlating these tw o events clearly is interactional in nature. O bserve, how ever, that neither infant beh avior at II or environm ent at E2 is studied, nor for that matter is II correlated with E2— thus the asym m etry. In general, the asymmetry o f this kind o f m odel centers on the failure to com pare the infant’ s effect on the caregiver; h ow ev er, even these com parisons w ou ld not render the m odel interactive. The secon d type o f m o d e l, seen in Figure 3, has m ore o f an interactionalist approach. Here again w e have tw o elem ents— the ch ild ’ s behavior and the environm ent— but here w e see that the various arrows connecting these elements are m ore interrelated. W hat w e ch ose to call these con nections is explicit in our theoretical orientation. For exam ple, the same infant behavior emitted under the same circum stances and responded to in the same manner could be called an elicitor or initiator;
lik ew ise, a behavior could be called a response or a
reinforcer. W hat w e ch o o se to call these con n ection s depends on many things. For exa m ple, if w e feel that the infant has intention, then his behavior is an elicitor, w hereas without this assum ption w e might refer to it as sim ply an
-------------------------- — r OR ^
ENVIRONMENT: THINGS PEOPLE
FIIC ITO R
' A s so cia tio n ,
Variability o f Growth and Maturity in Newborn Infants J. M. Tanner Institute o f Child Health and the University o f London
N ew born infants vary greatly in size, shape, and physical maturity. The standard deviation o f birth length, for exam ple, is about 4 % o f the mean birth length; the standard deviations o f height at age 5 , and at adulthood, are also approxim ately 4 % o f their m eans. The range o f new born w eigh t, in com parison with its m ean, is also sim ilar to the ranges at 5 and 18 years in similar com parison. The brain is no e x cep tio n ; the range o f brain w eight in new borns is about 200 to 500 gram s, and its standard deviation is about 13% o f its average (Larroche, 1968). Thus it is quite w ron g to think o f new borns as identical buds, from w hich in the fullness o f time flow er the variegated co lo rs o f the preschool assem bly. The new born already has had a lon g and eventful history. At birth he is in a highly dynam ic state o f change and developm en t, quite apart from the episode o f birth itself.
over-em ph asized.
p h y siolo g ica l alterations take place at or soon after birth as a direct consequence o f em ergen ce into a new environm ent, very many developm ental events, from the replacem ent o f fetal by adult h em og lob in (Jonxis, 1965) to the appearance o f con dition ed
indifferent to the fact o f birth; their progression has to await the striking o f som e differently regulated b io lo g ica l clo ck . Thus n ew born s, just like 6-yea r-old s or 14-year-olds— although perhaps not so o b v io u s ly — represent a w ide variety o f degrees o f p h y siological maturity; there is variation in advancem ent and retardation o f grow th, as w ell as in absolute size. On the D u b o w itz scale (see b e lo w ) the range amounts to the equivalent o f 3 to 4 w eeks o f age, even in infants all born at exactly 40 w eeks gestation. W hether these variations in size, shape, and maturity have an effect on the infant’ s caregiver w e do not at present k n o w ; but clearly they m ay have. W e m ight perhaps expect size itself to have a smaller effect than shape and b od y co m p ositio n (although I have been fo llo w in g the grow th o f a child with cerebral gigantism w h ose 2 -y ea r-old size at 6 m onths played h avoc with his m other’ s caregivin g beh avior, for she felt she was carrying around an enorm ity, like A lice
J. M. Tanner
with the P ig-B ab y). Infants characteristically put on subcutaneous fat rapidly after birth, and variations in the plum pness (esp ecially in strategic places such as the cheeks and bottom ) m ay w ell affect the careg iv er’ s responses. Sim ilarly, variation in the amount o f m uscle m ay be important, esp ecially in relation to the ca reg iv er’ s view o f the b a b y ’ s m asculinity or fem ininity (rem em ber the folk tales o f Starke Hans and the Infant H ercules). Besides these possible effects, o f w hich the caregiver m ay be on ly m arginally aware (as in the similar case o f sexually attracted adults), there is in our culture an effect o f w hich the mother is all too con sciou s. This is the am ount o f w eight gained by the baby during the first m onths after birth. Babies are expected to gain w eight (preferably in exact accordance with the tables published b y baby fo o d m anufacturers) and an insufficient gain is in itself a signal critical to, and som etim es critical o f, the m other. W e should therefore additionally bear in m ind the variations in w eight gain during infancy. In this chapter, then, I discuss: (1) variation in birth w eight and length; (2) variation in physical maturity com position o f new borns.
in shape and b od y
VARIATION IN BIRTH W E IG H T AND LENGTH Probably in new borns, as in children, length is a m ore satisfactory m easure o f body
than w eight,
dissim ilar tissues.
H ow ev er, length has been rather difficult to measure in the new born until the recent introduction o f the Harpenden neonatom eter, and fo r this reason it has not been required as routine in m ost countries (Sw eden and Switzerland being exception s). Even where it is m easured this is often done in a w ay that makes accuracy im possible. In the future, h ow ever, research studies on infants should certainly be organized in such a w ay that they have new born values for length (and skinfolds; see b e lo w ) as w ell as weight. For birth w eight, h ow ever, there are enorm ous num bers o f statistics. It is defined as the w eight o f the new born taken within the first hour after birth b efore significant postnatal w eight loss has occurred. (The next convenient point to measure weight after this time is at 4 w eeks postnatal). Birth w eight is affected b y : (1 ) length o f gestation; (2 ) parity (first, secon d , third, etc. in birth order); (3) sex; (4) maternal uterine and system ic characteristics, som e h ereditary ’ (5) so c io -e c o n o m ic circum stances and habits o f the m other. ’
Length of Gestation The average length o f gestation, traditionally m easured from the first day o f the last menstrual period (hence on average 14 days prior to actual fertilization) is 280 days, or 40 w eeks. H ow ev er, there is considerable individual variation about is figure (even when mistakes and inaccuracies in determ ining gestational age are set aside), and lengths o f gestation from 259 days (37 com p leted w eek s) to
Variability o f Growth and Maturity in Newborns
293 days (4 2 com pleted w eek s) are by international agreement regarded as norm al. B abies born within these limits are called term babies. Babies born earlier are called preterm babies, and those born later postterm babies. Until a fe w years a g o , all babies under the w eight o f 2 .5 kg were designated “ prem ature,”
whatever their gestation period or ph ysiological
definition (prom ulgated by the W H O in 1948) did a lot o f harm and has now been d rop ped; the w ord premature has com pletely disappeared from scientific use. B abies w eigh in g less than 2 .5 kg are called low -birth-w eight babies; this low birth w eight m ay be due to their being preterm babies or to their being babies w ho are pa th ologica lly small for their length o f gestation. These latter are defined as babies b e lo w the third centile, or two standard deviations, on standards for birth w eight w hich allow for length o f gestation (32 w eeks onw ard), sex, and parity o f m other ( e .g ., Tanner & T h om son , 1970). T hey are called light fo r dates (L F D ) babies. The prognosis for future developm ent o f babies w ho are preterm but not L F D is con siderably better than for those w ho are L F D . In the United K in gd om it is estimated that about on e-h alf to two-thirds o f the babies under 2 .5 kg are L F D ; the remainder are preterm but not L F D . Preterm babies can o f course be L F D also; about one-third are (Farr & M itchell, 1969). In Sw eden, the percentage o f babies under 2 .5 kg w h o are L F D seems to be low er (H edberg & H olm dall, 1970). In Figures la and lb the Tanner-T hom son birth w eight standards are given, show ing the increase o f w eight with gestation. The m axim um rate o f w eight grow th (peak w eight v elocity ) is reached, in w ell-nourished fetuses, at about 34 postmenstrual w eeks. From 34 to 36 w eeks the rate o f growth slow s dow n slightly, and from 36 to 40 w eeks it slow s very distinctly (Figures 2 and 3). This appears to be due to the influence o f the maternal uterus (see b e lo w ) w hose avail able space is b e co m in g fully occu p ied . T w in s slow dow n earlier, when their com b in ed w eight is approxim ately that o f the 36-w eek w eight o f a singleton fetus (M cK e o w n & R e co rd , 1952, 1953; N aeye, B enirschke, H agstrom , & M arcus, 1966). . Figure 2 serves to show the variation in w eight and length during the first year; but variation am ong children in rate o f grow th (v elocity ) cannot be envisaged from a “ dista n ce” chart such as this.
Parity Firstborn children are on average about 0 .1 0 kg lighter at birth than secon d -, third- and later-born (Figure 1). Firstborns grow a little faster than others on ce out o f the confines o f the uterus, h ow ev er, and so they make up the deficit by the end o f the first year (M inistry o f H ealth, 1959).
Sex B oys are larger than girls from at least 35 w eeks onward and by 40 w eeks average about 0 .1 5 kg m ore in w eight and 1.1 cm m ore in length.
J. M. Tanner
Maternal Uterine and Systemic Environment The slow in g dow n o f grow th after 34 or 36 w eeks appears to be due to the maternal environm ent. It occu rs in w ell-nourished fetuses, although less in them an in ill-nourished ones (see b e lo w ). N ew borns w hose grow th has been the m ost held up in the uterus have an increased v elocity o f grow th after birth representing a “ ca tch -u p ” similar to that w hich occurs in m alnourished children w hen
their nutritional deficit is corrected (Prader, Tanner, & V o n H arnack,
9 6 3 , Tanner, 1963). The upper chart in figure 4 illustrates this. The grow th o f children w h o w ere 5 to 6 lb, 6 to 7 lb , and so on at birth was fo llo w e d up to 3 l e7h' tance curves have their m inim um spread at about 2 U m onths after birth. This corresponds to the point o f m axim um postnatal v e lo city hence m axim um difference betw een the v elo city o f the 5-pounders and the 9-pounders (Figure 4 , bottom ). In these babies the catch-up is finished b y about 5 m onths- all he com pensation possible has presum ably been ach ieved , and from then o n ’ the larger-born
geom etrical considerations.
as ex p ected
there is a significant negative correlation
Variability o f Growth and Maturity in Newborns
f i g u r e l b . Figures la and lb are standards for birth w eigh t, accord in g to length o f gesta tion, parity, and sex. Further adjustm ent, not show n here, m ay be m ade fo r maternal size. (Charts prepared b y J. M . Tanner and R . H . W h iteh ou se, Institute o f C hild H ealth,
U niversity o f L o n d o n , from data b y A . H . T h o m so n , W . Z . B ille w icz and F. E . Hytten in J. O bstet. G y n a e c. Brit. C w lth ., 75, 9 0 3 , 1968. A ls o from Tanner & T h o m so n , 1970, from data o f T h o m so n , B ille w ic z , & H ytten, 1968).
betw een w eight at birth and w eight increm ent during the first 6 months after birth; the sam e is true o f birth length and length increm ent. In babies born to p o o rly nourished m others, the catch-up m ay continue for at least a year (B anik, N ayar, K rishna, R a y , & Tasker, 1972). This slo w in g dow n o f grow th betw een 34 and 40 w eeks enables a genetically large ch ild d ev elop in g in the uterus o f a small mother to be successfully delivered at the proper tim e. It operates in other species o f m ammals also; the m ost dram atic dem onstration was m ade by crossin g recip rocally a large Shire horse and a small Shetland p on y (W alton & H am m ond, 1938). The pair in w hich the m other was a Shire had a large new born fo a l, and the pair in which the m other was a Shetland had a small foa l. But both foals were the same size after a few m onths. The same occu rs in certain cattle crosses (D ick in son , 1960).
J. M. Tanner
The control acts therefore b y retarding grow th. R elatively small babies w ho are born to restraining m others, and w h o have large velocities after birth, must be born at a lesser maturity than the average. ’ The w ay in w hich the maternal control w orks is not k n ow n . A lth ough it is probab le that the effect proceed s from the uterus, it is uncertain whether system ic factors are also in volved. The placenta at first grow s m ore rapidly than the fetus, but from 30 w eeks onw ard this situation reverses, and the placenta/fetus w eight
c upine lengt u —o n
---- 34 33
/ / ' /■ / / / / , / / / / // ' / y
/ / ' ,
/ / /
/''"I , -27
' -26 -2 5
7 , / / ' // f/ 7, / //
/ / // s / , / // / / / , / / / // ' / t
/ / /
7, / // // V, >7 / / 77 / 7 / 77 7 // -f—
/// / ,h r 7 ' 7 / h 1—
A t je ,y e a rs
f i g u r e 2 b. Figures 2a and 2b are standards fo r grow th in length for b oy s and girls from birth to 2 years. B abies born b efore 4 0 w eek s should have their values plotted at the appropriate num ber o f w eek s gestation with subsequent values plotted in relation to this
“ co n ce p tio n
a g e .”
(F rom J. M . T anner, in A rneil and Forfar (E d s .), T ex tb o ok o f
P a ed ia trics, E dinburgh: L iv in g ston e, 1 9 7 3 .)
J. M. Tanner
8 12 16 20 24
FIGURE 2 c.
ratio begins to fall. It m ay be that the placenta sim ply cannot increase its capacity to supply nutriments sufficiently to maintain the rapid 3 4 -w eek w eight v e locity even in the average fetus. In fetuses g row in g in m others with small placentas, the deficit can be even m ore m arked. In m ice and guinea pigs hydrodyn am ic factors seem to be in volv ed , the size o f the placenta being dependent on the pressure at w h ich the maternal b lo o d reaches it, and the size o f the fetuses in turn depending on the size o f the placenta (M cL a ren , 1965). H ow ev er, placental m o rp h o lo g y
Variability o f Growth and Maturity in Newborns
W eig ht -
s JIO - -