As a result, when the reaction of three-year-olds to mother's brief absence is
compared
with that of two-year- olds, both crying and going to the closed door show a marked decrease.
Bowlby - Separation
Although often she succeeded in controlling herself, her constant preoccupation with not crying, which runs through the report, is evidence of the strain she was under.
Had there not been so many misconceptions about the norms of behaviour to be expected of young children when left, even briefly, in a strange place with strange people, it would have been unnecessary to present these data so fully. Yet misconceptions persist, especially among professional people. Again and again it is implied that a healthy normal child should not make a fuss when mother leaves, and that if he does so it is an indication either that mother spoils him or that he is suffering from some pathological anxiety. It is hoped that such reactions will be seen in a new and more realistic light when the natural history and function of attachment behaviour are understood.
Experimental studies
Because subjecting a child to a very brief separation, lasting only a few minutes, is ethically permissible, the behaviour to which it gives rise can be examined in experimental conditions;
41
variables can therefore be controlled and detailed systematic observation is relatively easy. Moreover, the behaviour of a child when his mother is absent can be compared with his behaviour when she is present, with other conditions remaining unchanged.
The first to undertake such studies was Arsenian ( 1943). In recent years a number of other workers have followed suit, for example Ainsworth ( Ainsworth & Wittig 1969; Ainsworth & Bell 1970), Rheingold ( 1969), Cox & Campbell ( 1968), Maccoby & Feldman ( 1972), Lee, Wright & Herbert (in preparation), and Marvin ( 1972). The overall picture that emerges of the behaviour of children as it develops from the first birthday through to the third is a consistent one.
Ainsworth's study is alluded to briefly in the first volume of this work (Chapter 16) when patterns of attachment are under consideration. Since that volume was written, she and her colleagues have published observations in more detail and on a much larger sample of children (for a recent review of findings see Ainsworth, Bell & Stayton, in press).
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The subjects of Ainsworth's study are fifty-six infants, aged one year, of white American middle-class families, reared within their family in ways typical of the 1960s. In respect of a subsample of twenty-three infants, detailed observations were made throughout the first year of life of the development of their social behaviour, with particular reference to attachment behaviour. In respect of the other thirty-three infants, limited observations of development were begun during their ninth month ( Bell 1970). Then the behaviour of all fifty-six babies was observed around the time of the first birthday. When a baby neared his birthday, 1 his mother was invited to participate with him in a brief series of experimental episodes, the purpose of which was to learn how the infant would behave in a congenial though slightly strange setting, first in the presence of mother and later in her absence.
To this end Ainsworth furnished a small room with three chairs and an open space in the middle. A chair near one end of the room was for mother, another, at the same end and opposite, was for a stranger, and a small chair at the other end had toys heaped upon it. The situation was designed to be novel enough to excite a child's interest but not so strange that he would be frightened. The entry of the stranger (female) was intended to be so gradual that any fear it evoked could be attributed to her unfamiliarity and not to any abrupt or alarming behaviour. There were eight experimental episodes, arranged so that the least disturbing ones came first; moreover, the series as a whole was similar in kind to many that an infant might be expected to encounter in his ordinary life. Both mother and stranger were instructed in advance regarding the roles they were to play. The episodes were arranged as follows.
In a preliminary episode a mother, accompanied by one of the observers, carried her infant into the room; the observer then left.
During episode 2, which lasted three minutes, mother put her infant down between the two chairs meant for the adults and then sat quietly in her own chair. She was not to participate in her infant's play unless he sought her attention, and then to do so only a little.
At the start of episode 3, which also lasted three minutes, the stranger entered. For one minute she sat quietly in her chair; then, for a second minute, she conversed with mother; finally,
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____________________
1 Thirty-three of the babies were aged forty-nine and fifty weeks, twenty-three were fifty-
one weeks old. -40-
for a third minute, she gently approached the infant showing him a toy. Meanwhile mother sat quietly.
Episode 4 began with mother leaving the room unobtrusively, leaving her handbag on the chair. If the infant was playing happily the stranger stayed quiet; but if he was inactive she tried to interest him in a toy. Should an infant become distressed she did what she could to distract him or comfort him. Like the previous two episodes, this one lasted three minutes; but if an infant was much distressed and could not be comforted the episode was curtailed.
Episode 5 began with mother's return, after which the stranger departed. On entering, mother was to pause in the doorway in order to see what her infant's spontaneous response to her return would be. Thenceforward she was free to do whatever suited -- to comfort him if required and to settle him afresh in play with the toys. Once he was settled she was to leave the room again, pausing briefly as she went to say 'bye-bye'.
During episode 6, in consequence, the infant was left all alone. Unless curtailed because of distress, this episode lasted the usual three minutes.
Thereafter first stranger and then mother returned to make episodes 7 and 8.
Throughout the series of episodes the behaviour of infant, mother, and stranger was recorded by observers from behind a one-way vision window. From the narrative record two measures of behaviour could be obtained for each infant: (a) the frequency with which different sorts of behaviour were shown during each episode, the frequency in every case being measured by scoring 1 for each period of fifteen seconds during which that behaviour was seen (thus, for a three-minute episode a score could range from zero to 12); (b) the intensity of certain kinds of behaviour shown during each episode; in making ratings of intensity it was often necessary to take account of how mother or stranger was behaving to the infant.
The finding to which attention is specially drawn in this chapter is that the behaviour of these fifty-six one-year-old infants during the episodes when mother was absent (nos. 4 and 6) was in every case much changed from what it had been during the earlier episode (no. 2) when mother was sitting quietly in the room with them. All the infants showed behaviour of a kind that everyone would describe as anxious or distressed, and as being due to his missing his mother.
During episode 2 while his mother was present, the typical
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picture of an infant was one of active interest in the scene. As a rule he moved around freely and played with the toys, giving only an occasional glance towards his mother; a small minority (seven infants), however, were inactive and tended to stay where they had been put.
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During this episode crying was conspicuous by its absence, though an occasional child whimpered for a few moments to begin with.
During episode 3, in which the stranger joined mother and infant, the behaviour of most of the children changed substantially. Staring at the stranger was almost universal; many infants moved rather closer to mother; and exploration and play diminished, on average to about half what they had been. Some infants showed a tendency to cry or grizzle; but in only five cases was crying of any intensity. As a rule the stranger was treated with interest and, fairly soon, with cautious friendliness.
During episode 4 mother had departed and infant found himself alone with stranger. Half the infants showed a strong tendency to seek mother, starting usually as soon as they realized she had gone. Eleven followed mother to the door or struggled to do so; the others either looked at the door frequently or for long periods, or else searched for mother in the chair on which she had been sitting. There was also much crying and other signs of distress. For the group as a whole there was four times as much crying during mother's absence as there had been during episode 3. A dozen infants cried practically the whole time and another thirteen for a part of it. In all, thirty-nine infants either cried or searched, or did both (thirteen cases). This leaves seventeen, a fairly substantial minority, who did neither.
The behaviour of the infants during episode 5, after mother had returned, is referred to again in Chapter 21. Suffice it to say that half of them actively approached mother and showed a clear desire to be close to her, while another six either signalled or approached in a less purposeful way. Thirteen of the more active ones, having achieved close physical contact with mother, maintained it both by clinging to her and by resisting her attempts to put them down. All who had been crying stopped doing so although some infants who had been acutely distressed were not comforted quickly.
During episode 6, after mother had departed again, this time leaving her infant all alone, searching and crying were seen in more infants and were also more intense than they had been during episode 4. On this occasion forty-four infants searched for mother, of whom thirty-one followed her to the door. Of the
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thirty-one, fourteen banged on the door or tried to open it: they either reached vainly for the knob or tried to insert their fingers into the crack. Among the dozen infants who did not search for mother, there were a few who had searched for her during the first separation episode but who on the second occasion showed only distress. During episode 6 there was also a great deal of crying. Forty infants cried more or less strongly; these included all those who had been distressed during the earlier episode as well as many others. Some rocked, or kicked their heels on the floor, or moved at random 'like a little trapped animal'. Only two infants neither searched nor cried; thirty did both.
Episode 6 was ended by stranger's return and the start of episode 7. After three minutes, during which infant was with stranger, mother returned and episode 8 began.
During episode 8, the tendencies to approach mother, to cling to her, and to resist being put down were much stronger and were seen in more of the infants than had been the case during the previous reunion episode. This time thirty-five of the fifty-six infants actively approached
44
mother and showed an evident desire for physical contact; a further nine either signalled their desire for contact or else approached mother in a less purposeful way. Two other infants, though they did not approach mother, engaged in lively interchange with her across a distance. Most striking was the large number of infants (forty-two) who both actively clung to mother and resisted being put down by her; another three, though they did not cling, resisted being put down.
A minority of infants included in the above figures showed signs of ambivalence towards mother of greater or less degree. Thus a few were seen to ignore mother briefly before approaching her, and others alternated between approaching and turning away. There were a few others who were so ambivalent that they mingled active attempts to seek and maintain contact with mother with attempts to get away from her.
A further small minority of infants (seven) behaved quite differently: they neither approached mother nor showed any desire to do so. Instead, they persistently ignored her and refused to respond when she invited them to come. Some even avoided looking at her.
To return to episodes 4 and 6: when behaviour shown during these two episodes, when mother was absent, is examined it is found that an infant was extremely likely either to search or to
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cry or to do both together. The table below shows the number of children who responded in one of these three ways for each episode.
Behaviour
Cry only Search only Search and cry Total (N = 56)
Episode
4 6
12 10 14 14 13 30 39 54
When the behaviour of any one infant in episode 6 is compared with what he showed in episode 4 the following sequences are found:
-- those who cried only in episode 4 were likely to do the same in episode 6
-- those who searched only in episode 4 were likely to search and cry in episode 6
-- those who searched and cried in episode 4 were likely to do the same in episode 6, though a few cried only.
The individual differences in the responses of these children are of great interest and (as is discussed in Chapter 21) are correlated with the different patterns of mother-child interaction observed in the preceding year. Here, however, our concern is with the features that the infants' responses had in common. On each occasion when mother left the room, first leaving infant with stranger and then leaving him all alone, the behaviour of every infant changed. Play and exploratory behaviour either slowed down or ceased altogether. On the second
45
occasion especially, all but two of the infants showed marked dislike of the situation and expressed it by seeking mother, by crying unhappily, or by doing both together. The extent of distress and anxiety during mother's absence was considerable, even though the room and the toys remained exactly as they had been.
While to describe the broad features of behaviour for the sample as a whole enables generalizations to be framed with confidence, it tends also to be a little impersonal. To illustrate something of what the series of episodes meant to one small boy
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and his mother, a description is given of one case, selected to be as representative as any one case can be: 1
1. Mother, Baby, Observer. Brian had one arm hooked over his mother's shoulder as they
came into the room; he was holding on to her, grasping a fold of her blouse. He looked
around soberly, but with interest, at the toys and at the observer.
2. Mother, Baby. After being put down, Brian immediately crept towards the toys and
began to explore them. He was very active, picking toys up, then dropping them or moving them about, with vigorous movements. He crept around quite a bit, mostly on his mother's side of the room. Although his attention was fixed on the playthings, he glanced up at his mother six times, and smiled at her twice. She glanced at him covertly, from time to time, but their glances did not seem to meet. Once he threw a toy with a clatter at her feet; she moved it back towards him. Otherwise there was no interaction between them. Towards the end of the three minutes he blew into a long cardboard tube, vocalizing as though pretending it were a horn, and then he looked up at his mother with a smile, seeming to expect her to acknowledge his accomplishment.
3. Stranger, Mother, Baby. He turned to look at the stranger when she entered, with a pleasant expression on his face. He played with the tube again, vocalized, smiled, and turned to glance at his mother. He continued to play, glancing at the stranger twice. When the stranger and his mother began to converse, he continued to explore actively at the end of the room, and looked up only once -- at the stranger. Towards the end of this minute of conversation he crept over to his mother, pulled himself up, and stood briefly, holding on to her knee with one hand, and clutching her blouse with the other. Then he turned back to play. When the stranger began her approach by leaning forward to offer him a toy he smiled, crept towards her, and reached for it. He put the toy in his mouth. She offered him the tube and he blew into it again. He looked back and forth from the toys to the stranger and did not look at his mother at all.
4. Stranger, Baby. He did not notice his mother leave. He continued to watch the stranger and the toys she was manipulating. Suddenly, he crept to his mother's chair, pulled
____________________
1 This description is taken from Ainsworth & Wittig ( 1969).
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himself up into a standing position, and looked at the stranger. She tried to distract him with a pull-toy. He approached the toy, and began to roll it back and forth; but he glanced again at his mother's empty chair. He was less active than he had been when alone with his mother, and after two minutes his activity ceased. He sat chewing the string of the pull-toy, and glancing from the stranger to his mother's chair. He made an unhappy noise, then a cry-face, and then he cried. The stranger tried to distract him by offering him a block; he took it but
46
then threw it away with a petulant gesture. He gave several more little protesting cries, but he did not cry hard.
5. Mother, Baby. When his mother opened the door and paused in the doorway, Brian looked at her immediately and vocalized loudly, with a quality that could have been either a laugh or a cry; then he crept to her quickly, and pulled himself up, with her help, to hold on to her knees. Then she picked him up, and he immediately put his arms around her neck, his face against her shoulder, and hugged her hard. He then gave her another big hug before she put him down. He resisted being put down; he tried to cling to her and protested loudly. Once on the floor, he threw himself down, hid his face in the rug, and cried angrily. His mother knelt beside him and tried to interest him in the toys again. He stopped crying and watched. After a moment she disengaged herself and got up to sit on her chair. He immediately threw himself down and cried again. She helped him to stand, and cuddled him. For a moment he reciprocated in the cuddle, but then he threw himself down on the floor again, crying. She again picked him up, and tried, to direct his attention to a squeaky ball. He looked at it, still holding on to his mother, with one arm hooked over her shoulder. He began to play, but quickly turned back to his mother with a brief cry, and clung to her. This alternation of play and clinging continued. After four and a half minutes, his mother, apparently not wishing to delay us, picked a moment when he was interested in a ball, and moved to the door.
6. Baby Alone. As she said 'bye-bye' and waved, Brian looked up with a little smile, but he shifted into a cry before she had quite closed the door. He sat crying, rocking himself back and forth. He cried hard, but occasionally lulled a little and looked around. After a minute and a half the episode was curtailed and stranger instructed to enter.
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7. Stranger, Baby. Brian lulled slightly when he saw the stranger enter, but he continued to cry. She first tried to distract him, then offered her arms to him. Brian responded by raising his arms; she picked him up, and he stopped crying immediately. She held him in her arms, and showed him the pictures tacked up around the edges of the mirrorwindow. He looked with apparent interest; he held on to her tightly, grasping a fold of her clothing. Occasionally he gave a little sob, but for the most part he did not cry. But when she put him down, he screamed. She picked him up again, and he lulled.
8. Mother, Baby. At the moment that his mother returned Brian was crying listlessly. He did not notice his mother. The stranger half-turned and pointed her out. Brian looked towards her, still crying, and then turned away. But he soon 'did a double take'. He looked back and vocalized a little protest. His mother offered her arms to him. He reached towards her, smiling, and leaned way out of the stranger's arms and his mother took him. He threw his arms around her neck, hugging her hard, and wiggling with excitement. Then the stranger tried to attract his attention. Brian did not notice her advance until she touched him; he immediately clung to his mother and buried his face in her shoulder. His mother continued to hold him, and he cuddled and clung to her, as the episode ended.
Since Ainsworth first reported her findings the results of several other studies have come to hand. In three of them ( Maccoby & Feldman 1972; Marvin 1972) the series of experimental situations used was planned to be as similar to Ainsworth's as possible, but in each the children were older. In a further two studies ( Cox & Campbell 1968; Leeet al. , in preparation) the situations differ from those used by Ainsworth, but in each there is opportunity to study children in an experimental setting first with mother present and later with mother absent. Details are given in the table overleaf.
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Because the last two studies listed give data comparing behaviour at one year with that to be seen at two years and onwards it is convenient to present findings from one of them first.
Preliminary findings reported by Lee and his colleagues show that, while attachment behaviour continues to be extremely active at the time of the second birthday, the behavioural system
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Authors
Maccoby & Feldman Maccoby & Feldman Marvin
Cox & Campbell
Leeet al.
Ages at children studied
2, 2 1/2, 3 years 2 1/2 years
2, 3, 4 years
14 months 24-37 months 1, 2, 3 years
which
Samples
White American 30-60, longitudinal
From Israeli kibbutzim 20, cross-sectional
White American 3 * 16, cross-sectional
White Canadian
2 * 20, cross-sectional
Middle-class English 27, longitudinal
governing it has altered in many respects since the first birthday. A comparison of the behaviour of the same children placed in the same situation at one year and two years of age shows that, at two years of age, children are likely:
-- to maintain greater proximity to mother -- a finding already reported from observations made out of doors by Anderson ( 1972a)
-- to be more hesitant in approaching a stranger.
On the other hand, merely to be close to mother and to be able to see her seem sufficient to give a child of two years a sense of security, whereas a one-year-old is likely to insist on physical contact. Two-year-olds, moreover, protest less than do oneyear-olds during a brief period when mother leaves them alone. Lee concludes that, compared with one-year-olds, two-yearolds have available more sophisticated cognitive strategies for maintaining contact with mother. They make much more use of looking and verbal communication, and are probably also using mental imagery in ways hardly possible for a one-yearold. As a result their attachment behaviour is better organized and their proximity-keeping is more proficient than it was when they were a year younger.
During the third year of life changes in the behaviour seen in the experimental situations are probably also in large part a result of the developments occurring in a child's cognitive competence. In their longitudinal study of children between
48
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their second and third birthdays, Maccoby & Feldman ( 1972) note the much greater ability of three-year-olds to communicate with mother over a distance and also their increased ability to understand, when mother leaves the room, that she will soon be returning.
As a result, when the reaction of three-year-olds to mother's brief absence is compared with that of two-year- olds, both crying and going to the closed door show a marked decrease. In addition, three- year-olds who have been left alone recover their equanimity when they are rejoined even by a stranger, whereas two-year-olds remain as upset when the stranger returns as they were when left entirely alone.
The responses of the children observed by Maccoby & Feldman when tested at the intermediate age of two and a half years in the same series of situations were roughly intermediate between the responses seen at two years and those seen at three years. Interestingly enough, the behaviour shown in the same situations by kibbutzim children at the age of two and a half differed very little from that of the American children at that age. Similarities between the groups were found in regard both to the means for the groups and to the range of individual variation within them. These findings are in keeping with other observations that suggest that the development of attachment behaviour in children brought up in kibbutzim is in most cases very similar to that of children brought up in traditional families (see Volume I, Chapter 15).
Although attachment behaviour develops in important ways during the second and third years of life, a child's behaviour in these experimental situations when mother is absent continues to be very different from what it is when she is present. For example, Maccoby & Feldman found that the manipulative play of two-year-olds decreased by about one-quarter when they were left with a stranger and by about half when they were left alone. Conversely, the proportion of children who cried increased enormously, from 5 per cent when mother was present to 30 per cent when the children were left with a stranger and to 53 per cent when they were left alone. Changes in the behaviour of three-year-olds when mother was absent were less striking than in two-year-olds but in the same direction. Their manipulative play decreased by one-sixth when they were left with a stranger and by one-third when they were left alone. The proportion of children who cried rose from zero to 5 per cent and 20 per cent respectively in the two situations in which mother was absent.
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In addition to crying after mother had departed, there were many children at each age-level who showed a desire to follow her. Of the two-year-olds, 30 per cent not only went to the door but made efforts to open it; and a further 21 per cent stood near the door or leaned against it. Of the three-year-olds, 34 per cent attempted to open the door, and nearly half of them banged on it vigorously. At each age-level, again, a substantial minority of children expressed anger at mother's absence: 19 per cent at two years, 31 per cent at two and a half years, and 14 per cent at three years.
In noting the increased activity observed when children were left alone, especially evident at the ages of two and two and a half, Maccoby & Feldman write:
This increased activity frequently took the form of anxious searching or agitated movement. There was occasionally a quite opposite kind of reaction to the stress of being alone: a kind of
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frozen immobility. . . . some children stood very still. This might occur near the door, when the child appeared to be waiting for his mother's return, or it might occur elsewhere in the room. In a few instances the child played with the toys, but each movement occurred at a markedly reduced speed, much as though the action had been rendered on a slow-motion film. Also, it occasionally happened that a child who was upset over separation would alternate between an unfocused running activity and immobility.
As regards the evaluation of these observations it is perhaps necessary to remind readers that on each occasion when mother departed she was absent for no more than three minutes, and for an even shorter time if the child was distressed, and that on the first of the two occasions the child was left with a friendly female stranger whom he had first met in the presence of mother. Furthermore, the toys he had been playing with were still there.
The findings of a cross-sectional study of samples of eight boys and eight girls at each of three age-levels by Marvin ( 1972) are in broad agreement with those of Maccoby & Feldman and here observations are extended to the fourth birthday. In Marvin's study the behaviour of boys and girls tended to differ. The two-year-old boys were as much upset as were Ainsworth's one-year-olds. Three-year-old boys were less upset than twoyear-olds; and four- year-old boys were comparatively little
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affected by any of the situations. By contrast, the two- and three-year-old girls were appreciably less affected by events than were one-year-olds, whereas the four-year-old girls were much more upset, especially by being left alone. An explanation suggested by Marvin of this last result, which is unexpected, is that a four-year-old girl may be especially disturbed by mother's apparently arbitrary behaviour in the test situation and by her unwillingness to cooperate when the child asks her not to leave her alone. Although in broad outline the findings of these different studies are consistent, there are many differences of detail. For example, neither Ainsworth with her one-year-olds nor Maccoby & Feldman with their two- and three-year-olds found sex differences of any magnitude; whereas Lee and his colleagues with their one- and two-year-olds and also Marvin with his twos, threes, and fours were struck by the differences between boys and girls. This and other discrepancies in the results reported in different studies are not easy to interpret. It seems not unlikely that relatively small differences in the arrangements for the testing, for example, in the behaviour of the stranger, can affect considerably the intensity, though not the form, of any behaviour exhibited. From these and other miniature separation experiments certain conclusions can be drawn:
a. In a benign but slightly strange situation, young children aged between eleven and thirty- six months, and brought up in families, are quick to notice mother's absence and commonly show some measure of concern, varying considerably but amounting very often to obvious, and in some cases to intense, anxiety and distress. Play activity decreases abruptly and may cease. Efforts to reach mother are common.
b. A child of two years is likely to be almost as upset in these situations as a child of one, and at neither age is he likely to make a quick recovery when rejoined either by mother or by a stranger.
c. A child of three is less likely to be upset in these situations and is more able to understand that mother will soon return. On being rejoined by mother or a stranger he is relatively quick to recover.
d. A child of four may either be little affected by the situations or else be much distressed by mother's apparently arbitrary behaviour.
50
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e. As children get older they are able to use vision and verbal communication as means for keeping in contact with mother; should they become upset when mother leaves the room older children will make more determined attempts to open the door in order to find her.
f. Up to 30 per cent of children are made angry by mother's leaving them alone in these circumstances.
g. In some studies and at some ages no differences are observed in the behaviour of boys and girls. In so far as any differences are observed, boys tend to explore more in mother's presence and to be more vigorous in their attempts to reach her when she has gone; girls tend to keep closer to mother and also to make friends more readily with the stranger.
A further finding from these miniature separation experiments, and one that links with the findings of Shirley ( 1942) and Heathers ( 1954) (see pp. 35 and 37 above), is only very recently reported. This is that when a child of about one year is tested in Ainsworth's series of episodes for a second time, a few weeks after the first testing, he is more upset and anxious than he was on the first occasion. When mother is present he keeps closer to her and clings more tightly. When she is absent he cries more ( Ainsworth, personal communication). These findings emerge from a test--retest study of twenty-four babies tested first at fifty weeks of age and a second time two weeks later. On the assumption that increased sensitivity is not due simply to maturation, which is unlikely, these findings provide the first experimental evidence that at one year of age a separation lasting only a few minutes, in what would ordinarily be regarded as a bland situation, is apt to leave a child more sensitive than he was before to a repetition of the experience.
Ontogeny of responses to separation The First Year
Since the responses to separation that are so unmistakable in infants of twelve months and older are not present at birth, it is clear that they must develop at some time during the first year of life. Unfortunately, studies designed to throw light on this development are few, and are confined to infants admitted to hospital. Nevertheless such evidence as is available is unambiguous. It is in keeping, moreover, with what is known about the
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development of attachment behaviour and about cognitive development generally.
In Chapter 15 of the earlier volume the steps by which, during the early months of life, an infant's attachment behaviour gradually becomes focused on a discriminated and preferred attachment figure are described. Development can be summarized as follows: before sixteen weeks differentially directed responses are few in number and are seen only when methods of observation are sensitive; between sixteen and twenty-six weeks differentially directed responses are both more numerous and more apparent; and in the great majority of family infants of six months and over they are plain for all to see. It comes as no surprise, therefore, that the full range of responses to separation described in earlier sections of this chapter is not seen before six or seven months of age.
Schaffer studied seventy-six infants of various ages under twelve months admitted to hospital: none was marasmic, deformed, or thought to be brain-damaged. Of the total, twentyfive were
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healthy infants admitted for elective surgery. While in hospital each child was observed during a two-hour session on each of the first three days (see Schaffer 1958; Schaffer & Callender 1959). Infants were not only without mother but had very little social interaction with nurses.
The responses observed in these twenty-five healthy infants differed greatly according to the child's age. The dividingpoint was twenty-eight weeks. Of the sixteen aged twenty-nine weeks and over, all but one fretted piteously, exhibiting all the struggling, restlessness, and crying so typical of two- and threeyear-olds. Of the nine aged twenty-eight weeks and under, by contrast, all but two 1 are reported to have accepted the situation without protest or fretting: only an unwonted and bewildered silence indicated their awareness of change.
Schaffer emphasizes that the shift from a bewildered response to active protest and fretting occurs suddenly and at full intensity at about twenty-eight weeks af age. Thus, of the sixteen infants aged between twenty-nine and fifty-one weeks, both the length of the period of fretting and the intensity of it were as great in those of seven and eight months as in those of eleven and twelve months.
Furthermore, responses both to the observers and to mother when she visited changed equally suddenly at about thirty weeks:
____________________
1 One of the exceptions was an infant already twenty-eight weeks of age.
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In the younger infants [twenty-eight weeks and less] most observation sessions showed these infants to be normally responsive, although the people confronting them were complete strangers. This held as much for the nurses who fed and bathed them as for the observers. . . . In the older group, on the other hand, normal [i. e. friendly] responsiveness was almost completely lacking, and the majority of observation sessions showed these infants to be negative and frightened when approached by a stranger-- a type of behaviour not seen at all in the younger group ( Schaffer & Callender 1959).
Although there were too few observations for statistical comparisons to be made of how infants of different ages responded to mother's visit, such observations as could be made support the thesis of a sharp change around twenty-eight to thirty weeks. Infants older than that mostly clung rather desperately to mother, behaviour that was in striking contrast to their negative responses to the observers. The younger infants, by contrast, tended to respond to mother and to observers without showing marked discrimination between them. Similarly, when mother departed, whereas older infants cried loudly and for a long time, even desperately, the younger ones showed no sign of protest.
Finally, the behaviour of the infants on their return home from hospital differed greatly according to age-group. Most of the infants aged seven months and over showed intense attachment behaviour. They clung almost continuously to mother, cried loud and long when left alone by her, and were notably afraid of strangers. Even figures formerly familiar, such as father and siblings, were sometimes regarded with suspicion. Infants aged under seven months, by contrast, showed little or no attachment behaviour during their early days at home. Their mothers described them as 'strange'. On the one hand, these infants seemed utterly
52
preoccupied in scanning the environment; on the other, they seemed unheedful of adults or perhaps averted their head when approached:
For hours on end sometimes the infant would crane his neck, scanning his surroundings without apparently focusing on any particular feature and letting his eyes sweep over all objects without attending to any particular one. A completely blank expression was usually observed on his face, though sometimes a bewildered or frightened look was reported. In the extreme form of this syndrome the infants were quite inactive throughout, apart from the scanning behaviour, and
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no vocalization was heard though one or two were reported to have cried or whimpered. When confronted with a toy the infant disregarded it.
To attempts by adults to make contact with them some of these younger infants seemed altogether oblivious. Others seemed to avoid the adults, and others again to gaze 'through' them with the same blank look that they used for the rest of the environment.
The only way in which the responses of the infants of the two age-groups were similar was in regard to sleep: in infants of both groups disturbed sleep and night-crying were common.
How the responses of infants of under seven months are best understood, and what their significance for an infant's future development may be, is difficult to know. It is plain, however, that the responses of these younger infants to separation are very different at every phase from those of older ones, and that it is only after about seven months of age that the patterns that are the subject of this work are to be seen.
In discussion of his findings Schaffer ( 1958) draws on Piaget's work on the development of an infant's concept of an object ( Piaget 1937). Only during the second half of the first year, Piaget finds, is there evidence that an infant is beginning to be able to conceive of an object as something that exists independently of himself, in a context of spatial and causal relations, even when it is not present to his perception, and so to search for it when it is missing. Bell ( 1970) confirms Piaget's findings and, in addition, reports the results of an experiment designed to test whether or not an infant develops a capacity to conceive of a person as a persisting object earlier than he develops the capacity in regard to inanimate things. Although her results show that a majority of infants develop the capacity in regard to a person earlier than in regard to things, it is not until about the ninth month that the capacity in regard to persons is reasonably well developed, and in a minority it lags some weeks behind that. For reasons to do with cognitive development, therefore, the types of response to separation with which we are concerned could hardly be expected in infants younger than those in whom they are seen.
Change after the First Birthday
All the evidence suggests that, once established, the typical patterns of response to being placed in strange surroundings
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53
with strange people do not undergo marked change, either in form or in intensity, much before the third birthday. Thenceforward their intensity begins to diminish, but only slowly. As an example, the change in Lottie's feelings about going to nursery school that appeared at the beginning of the third term, when she was aged two years and nine months (see above, p. 38 ), is characteristic of many children. Provided he knows where his mother is and has good reason to expect her to return soon, a child begins to accept another fairly familiar person, even when he is in a fairly unfamiliar place.
The only conditions at present known that reduce appreciably the effects of separation from mother are familiar possessions, the companionship of another and familiar child and, as Robertson & Robertson ( 1971) have shown, especially mothering from a skilled and familiar foster mother. By contrast, strange people, strange places, and strange proceedings are always alarming; and they are especially alarming when encountered alone (see Chapters 7 and 8). ?
Since distress at being separated unwillingly from an attachment figure is an indissoluble part of being attached to someone, changes occurring with age in the form of response to separation accompany, step by step, changes in the form that attachment behaviour takes. These changes are sketched in the first volume (Chapters 11 and 17) and need not be described further here. In so far as attachments to loved figures are an integral part of our lives, a potential to feel distress on separation from them and anxiety at the prospect of separation is so also. That is a theme running through the rest of this volume.
Meanwhile, in order that we may view the responses to separation seen in humans in a perspective broader than has been traditional, it is useful to compare the responses of young human children with those of the young of other species. When that is done it becomes evident that, just as attachment behaviour occurs in rather similar forms across a number of mammalian and avian species, so also do responses to separation. Here again man is no isolated case.
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Chapter 4
Behaviour with and without Mother: Non-human Primates
Man with all his noble qualities, with sympathy that feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system -- with all these exalted powers -- still bears in his bodily frame the indelible stamp of his lowly origin.
CHARLES DARWIN ( 1871)
Naturalistic observations
It has long been known that isolation and separation from a mother figure can cause distress, expressed in calling and searching, in the young of many species of bird and mammal. The 'lost piping' of young ducklings who have become attached to and have temporarily lost a mother figure is a familiar example. Others are the bleating of lambs and the yelping of puppies. Coming nearer man, there are numerous examples in the accounts of monkey and ape infants brought up by human caretakers. All accounts agree on the intensity of protest exhibited whenever a baby primate loses its mother figure, and the intensity of distress that follows when she cannot be found. All agree, too, on the intensity of clinging that occurs after the two are reunited.
For example, Bolwig ( 1963), in his account of the little patas monkey he reared from a few days old,1 describes how from the first the little monkey 'showed no fear of man, cried much, and panicked when left alone. . . . The screaming, with wide open mouth and distorted face, was only heard when the observer moved out of the monkey's immediate reach or sight. On such occasions he would more often than not run staggering to the nearest person in sight. ' Soon the monkey's attachment had become focused on Bolwig himself and then, until three and a
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1 See Volume I, Chapter 11.
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half months of age, the monkey could be very troublesome unless perpetually with his caretaker.
By the age of four months, however, the little monkey was exploring increasingly far afield and his master decided
to leave him for some hours every day in a cage with other monkeys of his own kind. This attempt was, however, not very successful. Although he knew the other monkeys well and was accustomed to play with them he panicked as soon as he knew I wanted to leave him
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behind, screamed, clung desperately to me and then tried to tear the door open. He would sit and cry until I finally let him out. Afterwards he would cling to me and refuse to leave me out of sight for the rest of the day. In the evening when asleep he would wake up with small shrieks and cling to me, showing all signs of terror when I tried to release his grip.
Accounts of similar behaviour are given of infant chimpanzees. Cathy Hayes ( 1951) recounts how Viki, a female she adopted at three days, would, when aged four months, cling to her foster mother
from the moment she left her crib until she was tucked in at night. . . . She sat on my lap while I ate or studied. She straddled my hip as I cooked. If she were on the floor, and I started to get away, she screamed and clung to my leg until I picked her up. . . . If some rare lack of vigilance on her part let a room's length separate us, she came charging across the abyss, screaming at the height of her considerable ability.
The Kelloggs, who did not adopt their female chimp, Gua, until she was seven months old and who kept her for nine months, report identical behaviour ( Kellogg & Kellogg 1933). They describe
an intensive and tenacious impulse to remain within sight and call of some friend, guardian, or protector. Throughout the entire nine months . . . whether indoors or out, she almost never roamed very far from someone she knew. To shut her up in a room by herself, or to walk away faster than she could run, and to leave her behind, proved, as well as we could judge, to be the most awful punishment that could possibly be inflicted. She could not be alone apparently without suffering.
Comparing Gua with their son, who was two and a half months older than she, the Kelloggs report:
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Both subjects displayed what might be called anxious behaviour (i. e. fretting and crying) if obvious preparations were being made by the grown-ups to leave the house. This led (in Gua) to an early understanding of the mechanism of door closing and a keen and continual observation of the doors in her vicinity. If she happened to be on one side of a doorway, and her friends on the other, the slightest movement of the door toward closing, whether produced by human hands or by the wind, would bring Gua rushing through the narrowing aperture, crying as she came.
The very detailed observations made by van Lawick-Goodall ( 1968) of chimpanzees in the Gombe Stream Reserve in central Africa show not only that anxious and distressed behaviour on being separated, as reported of animals in captivity, occurs also in the wild but that distress at separation continues throughout chimpanzee childhood. During the first year an infant is rarely out of actual contact with mother and, although from its first birthday onwards it spends more time out of contact, it none the less remains in proximity to her. Not until young are four and a half years of age are any of them seen travelling not in the company of mother, and then only rarely. 1
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Once an infant begins to spend time out of contact with mother, proximity is maintained largely by auditory signals. Either mother or infant emits a 'hoo' whimper to which the other promptly responds:
When the infant . . . begins to move from its mother, it invariably utters this sound if it gets into any difficulty and cannot quickly return to her. Until the infant's locomotor patterns are fairly well developed the mother normally responds by going to fetch it at once. The same sound is used by the mother when she reaches to remove her infant from some potentially dangerous situation or even, on occasion, as she gestures it to cling on when she is ready to go. The 'hoo' whimper therefore serves as a fairly specific signal in re-establishing mother-- infant contact.
Another signal used by infants is a scream; it is elicited whenever an infant falls or nearly falls from its mother or is frightened by a sudden loud noise. When her infant screams a mother almost unfailingly retrieves it and cradles it: 'On several occasions
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1 For a brief description of the developmental course of attachment behaviour in
chimpanzees see Volume I. Chanter 11. -59-
infants screamed loudly when their mothers started to move away without them. Each time the mothers immediately turned back and retrieved them. Indeed, throughout infancy, screaming normally results in the mother hurrying to rescue her child. '
Juveniles up to five or six years old also scream when lost or in trouble, and again mother usually hurries to the rescue:
On several occasions juveniles were observed who had accidentally lost their mothers. In each instance, after peering round from various trees, whimpering and screaming as they did so, they hurried off -- often in the wrong direction. On three occasions I was able to observe the reaction of the mother and every time, although she set off in the direction of her offspring's screaming, she herself made no sound to indicate her whereabouts.
In one case a juvenile female aged five years lost her mother in the evening and was still whimpering and crying the following morning. In another case, a juvenile stopped screaming before her mother found her, which resulted in a separation lasting several hours. (No information is available regarding behaviour of the young after reunion. )
Thus in these wild-living chimpanzees proximity of young to mother is maintained until pre- adolescence. Separations are rare, and usually quickly rectified by vocal signals and mutual search.
Early experimental studies
These naturalistic accounts show plainly not only that the attachment behaviour of young non- human primates is very similar to the attachment behaviour of young children but that their responses to separation are very similar also. Because of this, and because experimental separations lasting longer than minutes are inadmissible in the case of human young, more
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than one scientist has turned to monkey young for experimental subjects. A number of studies from at least four different centres are now published.
Had there not been so many misconceptions about the norms of behaviour to be expected of young children when left, even briefly, in a strange place with strange people, it would have been unnecessary to present these data so fully. Yet misconceptions persist, especially among professional people. Again and again it is implied that a healthy normal child should not make a fuss when mother leaves, and that if he does so it is an indication either that mother spoils him or that he is suffering from some pathological anxiety. It is hoped that such reactions will be seen in a new and more realistic light when the natural history and function of attachment behaviour are understood.
Experimental studies
Because subjecting a child to a very brief separation, lasting only a few minutes, is ethically permissible, the behaviour to which it gives rise can be examined in experimental conditions;
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variables can therefore be controlled and detailed systematic observation is relatively easy. Moreover, the behaviour of a child when his mother is absent can be compared with his behaviour when she is present, with other conditions remaining unchanged.
The first to undertake such studies was Arsenian ( 1943). In recent years a number of other workers have followed suit, for example Ainsworth ( Ainsworth & Wittig 1969; Ainsworth & Bell 1970), Rheingold ( 1969), Cox & Campbell ( 1968), Maccoby & Feldman ( 1972), Lee, Wright & Herbert (in preparation), and Marvin ( 1972). The overall picture that emerges of the behaviour of children as it develops from the first birthday through to the third is a consistent one.
Ainsworth's study is alluded to briefly in the first volume of this work (Chapter 16) when patterns of attachment are under consideration. Since that volume was written, she and her colleagues have published observations in more detail and on a much larger sample of children (for a recent review of findings see Ainsworth, Bell & Stayton, in press).
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The subjects of Ainsworth's study are fifty-six infants, aged one year, of white American middle-class families, reared within their family in ways typical of the 1960s. In respect of a subsample of twenty-three infants, detailed observations were made throughout the first year of life of the development of their social behaviour, with particular reference to attachment behaviour. In respect of the other thirty-three infants, limited observations of development were begun during their ninth month ( Bell 1970). Then the behaviour of all fifty-six babies was observed around the time of the first birthday. When a baby neared his birthday, 1 his mother was invited to participate with him in a brief series of experimental episodes, the purpose of which was to learn how the infant would behave in a congenial though slightly strange setting, first in the presence of mother and later in her absence.
To this end Ainsworth furnished a small room with three chairs and an open space in the middle. A chair near one end of the room was for mother, another, at the same end and opposite, was for a stranger, and a small chair at the other end had toys heaped upon it. The situation was designed to be novel enough to excite a child's interest but not so strange that he would be frightened. The entry of the stranger (female) was intended to be so gradual that any fear it evoked could be attributed to her unfamiliarity and not to any abrupt or alarming behaviour. There were eight experimental episodes, arranged so that the least disturbing ones came first; moreover, the series as a whole was similar in kind to many that an infant might be expected to encounter in his ordinary life. Both mother and stranger were instructed in advance regarding the roles they were to play. The episodes were arranged as follows.
In a preliminary episode a mother, accompanied by one of the observers, carried her infant into the room; the observer then left.
During episode 2, which lasted three minutes, mother put her infant down between the two chairs meant for the adults and then sat quietly in her own chair. She was not to participate in her infant's play unless he sought her attention, and then to do so only a little.
At the start of episode 3, which also lasted three minutes, the stranger entered. For one minute she sat quietly in her chair; then, for a second minute, she conversed with mother; finally,
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1 Thirty-three of the babies were aged forty-nine and fifty weeks, twenty-three were fifty-
one weeks old. -40-
for a third minute, she gently approached the infant showing him a toy. Meanwhile mother sat quietly.
Episode 4 began with mother leaving the room unobtrusively, leaving her handbag on the chair. If the infant was playing happily the stranger stayed quiet; but if he was inactive she tried to interest him in a toy. Should an infant become distressed she did what she could to distract him or comfort him. Like the previous two episodes, this one lasted three minutes; but if an infant was much distressed and could not be comforted the episode was curtailed.
Episode 5 began with mother's return, after which the stranger departed. On entering, mother was to pause in the doorway in order to see what her infant's spontaneous response to her return would be. Thenceforward she was free to do whatever suited -- to comfort him if required and to settle him afresh in play with the toys. Once he was settled she was to leave the room again, pausing briefly as she went to say 'bye-bye'.
During episode 6, in consequence, the infant was left all alone. Unless curtailed because of distress, this episode lasted the usual three minutes.
Thereafter first stranger and then mother returned to make episodes 7 and 8.
Throughout the series of episodes the behaviour of infant, mother, and stranger was recorded by observers from behind a one-way vision window. From the narrative record two measures of behaviour could be obtained for each infant: (a) the frequency with which different sorts of behaviour were shown during each episode, the frequency in every case being measured by scoring 1 for each period of fifteen seconds during which that behaviour was seen (thus, for a three-minute episode a score could range from zero to 12); (b) the intensity of certain kinds of behaviour shown during each episode; in making ratings of intensity it was often necessary to take account of how mother or stranger was behaving to the infant.
The finding to which attention is specially drawn in this chapter is that the behaviour of these fifty-six one-year-old infants during the episodes when mother was absent (nos. 4 and 6) was in every case much changed from what it had been during the earlier episode (no. 2) when mother was sitting quietly in the room with them. All the infants showed behaviour of a kind that everyone would describe as anxious or distressed, and as being due to his missing his mother.
During episode 2 while his mother was present, the typical
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picture of an infant was one of active interest in the scene. As a rule he moved around freely and played with the toys, giving only an occasional glance towards his mother; a small minority (seven infants), however, were inactive and tended to stay where they had been put.
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During this episode crying was conspicuous by its absence, though an occasional child whimpered for a few moments to begin with.
During episode 3, in which the stranger joined mother and infant, the behaviour of most of the children changed substantially. Staring at the stranger was almost universal; many infants moved rather closer to mother; and exploration and play diminished, on average to about half what they had been. Some infants showed a tendency to cry or grizzle; but in only five cases was crying of any intensity. As a rule the stranger was treated with interest and, fairly soon, with cautious friendliness.
During episode 4 mother had departed and infant found himself alone with stranger. Half the infants showed a strong tendency to seek mother, starting usually as soon as they realized she had gone. Eleven followed mother to the door or struggled to do so; the others either looked at the door frequently or for long periods, or else searched for mother in the chair on which she had been sitting. There was also much crying and other signs of distress. For the group as a whole there was four times as much crying during mother's absence as there had been during episode 3. A dozen infants cried practically the whole time and another thirteen for a part of it. In all, thirty-nine infants either cried or searched, or did both (thirteen cases). This leaves seventeen, a fairly substantial minority, who did neither.
The behaviour of the infants during episode 5, after mother had returned, is referred to again in Chapter 21. Suffice it to say that half of them actively approached mother and showed a clear desire to be close to her, while another six either signalled or approached in a less purposeful way. Thirteen of the more active ones, having achieved close physical contact with mother, maintained it both by clinging to her and by resisting her attempts to put them down. All who had been crying stopped doing so although some infants who had been acutely distressed were not comforted quickly.
During episode 6, after mother had departed again, this time leaving her infant all alone, searching and crying were seen in more infants and were also more intense than they had been during episode 4. On this occasion forty-four infants searched for mother, of whom thirty-one followed her to the door. Of the
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thirty-one, fourteen banged on the door or tried to open it: they either reached vainly for the knob or tried to insert their fingers into the crack. Among the dozen infants who did not search for mother, there were a few who had searched for her during the first separation episode but who on the second occasion showed only distress. During episode 6 there was also a great deal of crying. Forty infants cried more or less strongly; these included all those who had been distressed during the earlier episode as well as many others. Some rocked, or kicked their heels on the floor, or moved at random 'like a little trapped animal'. Only two infants neither searched nor cried; thirty did both.
Episode 6 was ended by stranger's return and the start of episode 7. After three minutes, during which infant was with stranger, mother returned and episode 8 began.
During episode 8, the tendencies to approach mother, to cling to her, and to resist being put down were much stronger and were seen in more of the infants than had been the case during the previous reunion episode. This time thirty-five of the fifty-six infants actively approached
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mother and showed an evident desire for physical contact; a further nine either signalled their desire for contact or else approached mother in a less purposeful way. Two other infants, though they did not approach mother, engaged in lively interchange with her across a distance. Most striking was the large number of infants (forty-two) who both actively clung to mother and resisted being put down by her; another three, though they did not cling, resisted being put down.
A minority of infants included in the above figures showed signs of ambivalence towards mother of greater or less degree. Thus a few were seen to ignore mother briefly before approaching her, and others alternated between approaching and turning away. There were a few others who were so ambivalent that they mingled active attempts to seek and maintain contact with mother with attempts to get away from her.
A further small minority of infants (seven) behaved quite differently: they neither approached mother nor showed any desire to do so. Instead, they persistently ignored her and refused to respond when she invited them to come. Some even avoided looking at her.
To return to episodes 4 and 6: when behaviour shown during these two episodes, when mother was absent, is examined it is found that an infant was extremely likely either to search or to
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cry or to do both together. The table below shows the number of children who responded in one of these three ways for each episode.
Behaviour
Cry only Search only Search and cry Total (N = 56)
Episode
4 6
12 10 14 14 13 30 39 54
When the behaviour of any one infant in episode 6 is compared with what he showed in episode 4 the following sequences are found:
-- those who cried only in episode 4 were likely to do the same in episode 6
-- those who searched only in episode 4 were likely to search and cry in episode 6
-- those who searched and cried in episode 4 were likely to do the same in episode 6, though a few cried only.
The individual differences in the responses of these children are of great interest and (as is discussed in Chapter 21) are correlated with the different patterns of mother-child interaction observed in the preceding year. Here, however, our concern is with the features that the infants' responses had in common. On each occasion when mother left the room, first leaving infant with stranger and then leaving him all alone, the behaviour of every infant changed. Play and exploratory behaviour either slowed down or ceased altogether. On the second
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occasion especially, all but two of the infants showed marked dislike of the situation and expressed it by seeking mother, by crying unhappily, or by doing both together. The extent of distress and anxiety during mother's absence was considerable, even though the room and the toys remained exactly as they had been.
While to describe the broad features of behaviour for the sample as a whole enables generalizations to be framed with confidence, it tends also to be a little impersonal. To illustrate something of what the series of episodes meant to one small boy
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and his mother, a description is given of one case, selected to be as representative as any one case can be: 1
1. Mother, Baby, Observer. Brian had one arm hooked over his mother's shoulder as they
came into the room; he was holding on to her, grasping a fold of her blouse. He looked
around soberly, but with interest, at the toys and at the observer.
2. Mother, Baby. After being put down, Brian immediately crept towards the toys and
began to explore them. He was very active, picking toys up, then dropping them or moving them about, with vigorous movements. He crept around quite a bit, mostly on his mother's side of the room. Although his attention was fixed on the playthings, he glanced up at his mother six times, and smiled at her twice. She glanced at him covertly, from time to time, but their glances did not seem to meet. Once he threw a toy with a clatter at her feet; she moved it back towards him. Otherwise there was no interaction between them. Towards the end of the three minutes he blew into a long cardboard tube, vocalizing as though pretending it were a horn, and then he looked up at his mother with a smile, seeming to expect her to acknowledge his accomplishment.
3. Stranger, Mother, Baby. He turned to look at the stranger when she entered, with a pleasant expression on his face. He played with the tube again, vocalized, smiled, and turned to glance at his mother. He continued to play, glancing at the stranger twice. When the stranger and his mother began to converse, he continued to explore actively at the end of the room, and looked up only once -- at the stranger. Towards the end of this minute of conversation he crept over to his mother, pulled himself up, and stood briefly, holding on to her knee with one hand, and clutching her blouse with the other. Then he turned back to play. When the stranger began her approach by leaning forward to offer him a toy he smiled, crept towards her, and reached for it. He put the toy in his mouth. She offered him the tube and he blew into it again. He looked back and forth from the toys to the stranger and did not look at his mother at all.
4. Stranger, Baby. He did not notice his mother leave. He continued to watch the stranger and the toys she was manipulating. Suddenly, he crept to his mother's chair, pulled
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1 This description is taken from Ainsworth & Wittig ( 1969).
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himself up into a standing position, and looked at the stranger. She tried to distract him with a pull-toy. He approached the toy, and began to roll it back and forth; but he glanced again at his mother's empty chair. He was less active than he had been when alone with his mother, and after two minutes his activity ceased. He sat chewing the string of the pull-toy, and glancing from the stranger to his mother's chair. He made an unhappy noise, then a cry-face, and then he cried. The stranger tried to distract him by offering him a block; he took it but
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then threw it away with a petulant gesture. He gave several more little protesting cries, but he did not cry hard.
5. Mother, Baby. When his mother opened the door and paused in the doorway, Brian looked at her immediately and vocalized loudly, with a quality that could have been either a laugh or a cry; then he crept to her quickly, and pulled himself up, with her help, to hold on to her knees. Then she picked him up, and he immediately put his arms around her neck, his face against her shoulder, and hugged her hard. He then gave her another big hug before she put him down. He resisted being put down; he tried to cling to her and protested loudly. Once on the floor, he threw himself down, hid his face in the rug, and cried angrily. His mother knelt beside him and tried to interest him in the toys again. He stopped crying and watched. After a moment she disengaged herself and got up to sit on her chair. He immediately threw himself down and cried again. She helped him to stand, and cuddled him. For a moment he reciprocated in the cuddle, but then he threw himself down on the floor again, crying. She again picked him up, and tried, to direct his attention to a squeaky ball. He looked at it, still holding on to his mother, with one arm hooked over her shoulder. He began to play, but quickly turned back to his mother with a brief cry, and clung to her. This alternation of play and clinging continued. After four and a half minutes, his mother, apparently not wishing to delay us, picked a moment when he was interested in a ball, and moved to the door.
6. Baby Alone. As she said 'bye-bye' and waved, Brian looked up with a little smile, but he shifted into a cry before she had quite closed the door. He sat crying, rocking himself back and forth. He cried hard, but occasionally lulled a little and looked around. After a minute and a half the episode was curtailed and stranger instructed to enter.
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7. Stranger, Baby. Brian lulled slightly when he saw the stranger enter, but he continued to cry. She first tried to distract him, then offered her arms to him. Brian responded by raising his arms; she picked him up, and he stopped crying immediately. She held him in her arms, and showed him the pictures tacked up around the edges of the mirrorwindow. He looked with apparent interest; he held on to her tightly, grasping a fold of her clothing. Occasionally he gave a little sob, but for the most part he did not cry. But when she put him down, he screamed. She picked him up again, and he lulled.
8. Mother, Baby. At the moment that his mother returned Brian was crying listlessly. He did not notice his mother. The stranger half-turned and pointed her out. Brian looked towards her, still crying, and then turned away. But he soon 'did a double take'. He looked back and vocalized a little protest. His mother offered her arms to him. He reached towards her, smiling, and leaned way out of the stranger's arms and his mother took him. He threw his arms around her neck, hugging her hard, and wiggling with excitement. Then the stranger tried to attract his attention. Brian did not notice her advance until she touched him; he immediately clung to his mother and buried his face in her shoulder. His mother continued to hold him, and he cuddled and clung to her, as the episode ended.
Since Ainsworth first reported her findings the results of several other studies have come to hand. In three of them ( Maccoby & Feldman 1972; Marvin 1972) the series of experimental situations used was planned to be as similar to Ainsworth's as possible, but in each the children were older. In a further two studies ( Cox & Campbell 1968; Leeet al. , in preparation) the situations differ from those used by Ainsworth, but in each there is opportunity to study children in an experimental setting first with mother present and later with mother absent. Details are given in the table overleaf.
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Because the last two studies listed give data comparing behaviour at one year with that to be seen at two years and onwards it is convenient to present findings from one of them first.
Preliminary findings reported by Lee and his colleagues show that, while attachment behaviour continues to be extremely active at the time of the second birthday, the behavioural system
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Authors
Maccoby & Feldman Maccoby & Feldman Marvin
Cox & Campbell
Leeet al.
Ages at children studied
2, 2 1/2, 3 years 2 1/2 years
2, 3, 4 years
14 months 24-37 months 1, 2, 3 years
which
Samples
White American 30-60, longitudinal
From Israeli kibbutzim 20, cross-sectional
White American 3 * 16, cross-sectional
White Canadian
2 * 20, cross-sectional
Middle-class English 27, longitudinal
governing it has altered in many respects since the first birthday. A comparison of the behaviour of the same children placed in the same situation at one year and two years of age shows that, at two years of age, children are likely:
-- to maintain greater proximity to mother -- a finding already reported from observations made out of doors by Anderson ( 1972a)
-- to be more hesitant in approaching a stranger.
On the other hand, merely to be close to mother and to be able to see her seem sufficient to give a child of two years a sense of security, whereas a one-year-old is likely to insist on physical contact. Two-year-olds, moreover, protest less than do oneyear-olds during a brief period when mother leaves them alone. Lee concludes that, compared with one-year-olds, two-yearolds have available more sophisticated cognitive strategies for maintaining contact with mother. They make much more use of looking and verbal communication, and are probably also using mental imagery in ways hardly possible for a one-yearold. As a result their attachment behaviour is better organized and their proximity-keeping is more proficient than it was when they were a year younger.
During the third year of life changes in the behaviour seen in the experimental situations are probably also in large part a result of the developments occurring in a child's cognitive competence. In their longitudinal study of children between
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their second and third birthdays, Maccoby & Feldman ( 1972) note the much greater ability of three-year-olds to communicate with mother over a distance and also their increased ability to understand, when mother leaves the room, that she will soon be returning.
As a result, when the reaction of three-year-olds to mother's brief absence is compared with that of two-year- olds, both crying and going to the closed door show a marked decrease. In addition, three- year-olds who have been left alone recover their equanimity when they are rejoined even by a stranger, whereas two-year-olds remain as upset when the stranger returns as they were when left entirely alone.
The responses of the children observed by Maccoby & Feldman when tested at the intermediate age of two and a half years in the same series of situations were roughly intermediate between the responses seen at two years and those seen at three years. Interestingly enough, the behaviour shown in the same situations by kibbutzim children at the age of two and a half differed very little from that of the American children at that age. Similarities between the groups were found in regard both to the means for the groups and to the range of individual variation within them. These findings are in keeping with other observations that suggest that the development of attachment behaviour in children brought up in kibbutzim is in most cases very similar to that of children brought up in traditional families (see Volume I, Chapter 15).
Although attachment behaviour develops in important ways during the second and third years of life, a child's behaviour in these experimental situations when mother is absent continues to be very different from what it is when she is present. For example, Maccoby & Feldman found that the manipulative play of two-year-olds decreased by about one-quarter when they were left with a stranger and by about half when they were left alone. Conversely, the proportion of children who cried increased enormously, from 5 per cent when mother was present to 30 per cent when the children were left with a stranger and to 53 per cent when they were left alone. Changes in the behaviour of three-year-olds when mother was absent were less striking than in two-year-olds but in the same direction. Their manipulative play decreased by one-sixth when they were left with a stranger and by one-third when they were left alone. The proportion of children who cried rose from zero to 5 per cent and 20 per cent respectively in the two situations in which mother was absent.
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In addition to crying after mother had departed, there were many children at each age-level who showed a desire to follow her. Of the two-year-olds, 30 per cent not only went to the door but made efforts to open it; and a further 21 per cent stood near the door or leaned against it. Of the three-year-olds, 34 per cent attempted to open the door, and nearly half of them banged on it vigorously. At each age-level, again, a substantial minority of children expressed anger at mother's absence: 19 per cent at two years, 31 per cent at two and a half years, and 14 per cent at three years.
In noting the increased activity observed when children were left alone, especially evident at the ages of two and two and a half, Maccoby & Feldman write:
This increased activity frequently took the form of anxious searching or agitated movement. There was occasionally a quite opposite kind of reaction to the stress of being alone: a kind of
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frozen immobility. . . . some children stood very still. This might occur near the door, when the child appeared to be waiting for his mother's return, or it might occur elsewhere in the room. In a few instances the child played with the toys, but each movement occurred at a markedly reduced speed, much as though the action had been rendered on a slow-motion film. Also, it occasionally happened that a child who was upset over separation would alternate between an unfocused running activity and immobility.
As regards the evaluation of these observations it is perhaps necessary to remind readers that on each occasion when mother departed she was absent for no more than three minutes, and for an even shorter time if the child was distressed, and that on the first of the two occasions the child was left with a friendly female stranger whom he had first met in the presence of mother. Furthermore, the toys he had been playing with were still there.
The findings of a cross-sectional study of samples of eight boys and eight girls at each of three age-levels by Marvin ( 1972) are in broad agreement with those of Maccoby & Feldman and here observations are extended to the fourth birthday. In Marvin's study the behaviour of boys and girls tended to differ. The two-year-old boys were as much upset as were Ainsworth's one-year-olds. Three-year-old boys were less upset than twoyear-olds; and four- year-old boys were comparatively little
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affected by any of the situations. By contrast, the two- and three-year-old girls were appreciably less affected by events than were one-year-olds, whereas the four-year-old girls were much more upset, especially by being left alone. An explanation suggested by Marvin of this last result, which is unexpected, is that a four-year-old girl may be especially disturbed by mother's apparently arbitrary behaviour in the test situation and by her unwillingness to cooperate when the child asks her not to leave her alone. Although in broad outline the findings of these different studies are consistent, there are many differences of detail. For example, neither Ainsworth with her one-year-olds nor Maccoby & Feldman with their two- and three-year-olds found sex differences of any magnitude; whereas Lee and his colleagues with their one- and two-year-olds and also Marvin with his twos, threes, and fours were struck by the differences between boys and girls. This and other discrepancies in the results reported in different studies are not easy to interpret. It seems not unlikely that relatively small differences in the arrangements for the testing, for example, in the behaviour of the stranger, can affect considerably the intensity, though not the form, of any behaviour exhibited. From these and other miniature separation experiments certain conclusions can be drawn:
a. In a benign but slightly strange situation, young children aged between eleven and thirty- six months, and brought up in families, are quick to notice mother's absence and commonly show some measure of concern, varying considerably but amounting very often to obvious, and in some cases to intense, anxiety and distress. Play activity decreases abruptly and may cease. Efforts to reach mother are common.
b. A child of two years is likely to be almost as upset in these situations as a child of one, and at neither age is he likely to make a quick recovery when rejoined either by mother or by a stranger.
c. A child of three is less likely to be upset in these situations and is more able to understand that mother will soon return. On being rejoined by mother or a stranger he is relatively quick to recover.
d. A child of four may either be little affected by the situations or else be much distressed by mother's apparently arbitrary behaviour.
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e. As children get older they are able to use vision and verbal communication as means for keeping in contact with mother; should they become upset when mother leaves the room older children will make more determined attempts to open the door in order to find her.
f. Up to 30 per cent of children are made angry by mother's leaving them alone in these circumstances.
g. In some studies and at some ages no differences are observed in the behaviour of boys and girls. In so far as any differences are observed, boys tend to explore more in mother's presence and to be more vigorous in their attempts to reach her when she has gone; girls tend to keep closer to mother and also to make friends more readily with the stranger.
A further finding from these miniature separation experiments, and one that links with the findings of Shirley ( 1942) and Heathers ( 1954) (see pp. 35 and 37 above), is only very recently reported. This is that when a child of about one year is tested in Ainsworth's series of episodes for a second time, a few weeks after the first testing, he is more upset and anxious than he was on the first occasion. When mother is present he keeps closer to her and clings more tightly. When she is absent he cries more ( Ainsworth, personal communication). These findings emerge from a test--retest study of twenty-four babies tested first at fifty weeks of age and a second time two weeks later. On the assumption that increased sensitivity is not due simply to maturation, which is unlikely, these findings provide the first experimental evidence that at one year of age a separation lasting only a few minutes, in what would ordinarily be regarded as a bland situation, is apt to leave a child more sensitive than he was before to a repetition of the experience.
Ontogeny of responses to separation The First Year
Since the responses to separation that are so unmistakable in infants of twelve months and older are not present at birth, it is clear that they must develop at some time during the first year of life. Unfortunately, studies designed to throw light on this development are few, and are confined to infants admitted to hospital. Nevertheless such evidence as is available is unambiguous. It is in keeping, moreover, with what is known about the
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development of attachment behaviour and about cognitive development generally.
In Chapter 15 of the earlier volume the steps by which, during the early months of life, an infant's attachment behaviour gradually becomes focused on a discriminated and preferred attachment figure are described. Development can be summarized as follows: before sixteen weeks differentially directed responses are few in number and are seen only when methods of observation are sensitive; between sixteen and twenty-six weeks differentially directed responses are both more numerous and more apparent; and in the great majority of family infants of six months and over they are plain for all to see. It comes as no surprise, therefore, that the full range of responses to separation described in earlier sections of this chapter is not seen before six or seven months of age.
Schaffer studied seventy-six infants of various ages under twelve months admitted to hospital: none was marasmic, deformed, or thought to be brain-damaged. Of the total, twentyfive were
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healthy infants admitted for elective surgery. While in hospital each child was observed during a two-hour session on each of the first three days (see Schaffer 1958; Schaffer & Callender 1959). Infants were not only without mother but had very little social interaction with nurses.
The responses observed in these twenty-five healthy infants differed greatly according to the child's age. The dividingpoint was twenty-eight weeks. Of the sixteen aged twenty-nine weeks and over, all but one fretted piteously, exhibiting all the struggling, restlessness, and crying so typical of two- and threeyear-olds. Of the nine aged twenty-eight weeks and under, by contrast, all but two 1 are reported to have accepted the situation without protest or fretting: only an unwonted and bewildered silence indicated their awareness of change.
Schaffer emphasizes that the shift from a bewildered response to active protest and fretting occurs suddenly and at full intensity at about twenty-eight weeks af age. Thus, of the sixteen infants aged between twenty-nine and fifty-one weeks, both the length of the period of fretting and the intensity of it were as great in those of seven and eight months as in those of eleven and twelve months.
Furthermore, responses both to the observers and to mother when she visited changed equally suddenly at about thirty weeks:
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1 One of the exceptions was an infant already twenty-eight weeks of age.
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In the younger infants [twenty-eight weeks and less] most observation sessions showed these infants to be normally responsive, although the people confronting them were complete strangers. This held as much for the nurses who fed and bathed them as for the observers. . . . In the older group, on the other hand, normal [i. e. friendly] responsiveness was almost completely lacking, and the majority of observation sessions showed these infants to be negative and frightened when approached by a stranger-- a type of behaviour not seen at all in the younger group ( Schaffer & Callender 1959).
Although there were too few observations for statistical comparisons to be made of how infants of different ages responded to mother's visit, such observations as could be made support the thesis of a sharp change around twenty-eight to thirty weeks. Infants older than that mostly clung rather desperately to mother, behaviour that was in striking contrast to their negative responses to the observers. The younger infants, by contrast, tended to respond to mother and to observers without showing marked discrimination between them. Similarly, when mother departed, whereas older infants cried loudly and for a long time, even desperately, the younger ones showed no sign of protest.
Finally, the behaviour of the infants on their return home from hospital differed greatly according to age-group. Most of the infants aged seven months and over showed intense attachment behaviour. They clung almost continuously to mother, cried loud and long when left alone by her, and were notably afraid of strangers. Even figures formerly familiar, such as father and siblings, were sometimes regarded with suspicion. Infants aged under seven months, by contrast, showed little or no attachment behaviour during their early days at home. Their mothers described them as 'strange'. On the one hand, these infants seemed utterly
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preoccupied in scanning the environment; on the other, they seemed unheedful of adults or perhaps averted their head when approached:
For hours on end sometimes the infant would crane his neck, scanning his surroundings without apparently focusing on any particular feature and letting his eyes sweep over all objects without attending to any particular one. A completely blank expression was usually observed on his face, though sometimes a bewildered or frightened look was reported. In the extreme form of this syndrome the infants were quite inactive throughout, apart from the scanning behaviour, and
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no vocalization was heard though one or two were reported to have cried or whimpered. When confronted with a toy the infant disregarded it.
To attempts by adults to make contact with them some of these younger infants seemed altogether oblivious. Others seemed to avoid the adults, and others again to gaze 'through' them with the same blank look that they used for the rest of the environment.
The only way in which the responses of the infants of the two age-groups were similar was in regard to sleep: in infants of both groups disturbed sleep and night-crying were common.
How the responses of infants of under seven months are best understood, and what their significance for an infant's future development may be, is difficult to know. It is plain, however, that the responses of these younger infants to separation are very different at every phase from those of older ones, and that it is only after about seven months of age that the patterns that are the subject of this work are to be seen.
In discussion of his findings Schaffer ( 1958) draws on Piaget's work on the development of an infant's concept of an object ( Piaget 1937). Only during the second half of the first year, Piaget finds, is there evidence that an infant is beginning to be able to conceive of an object as something that exists independently of himself, in a context of spatial and causal relations, even when it is not present to his perception, and so to search for it when it is missing. Bell ( 1970) confirms Piaget's findings and, in addition, reports the results of an experiment designed to test whether or not an infant develops a capacity to conceive of a person as a persisting object earlier than he develops the capacity in regard to inanimate things. Although her results show that a majority of infants develop the capacity in regard to a person earlier than in regard to things, it is not until about the ninth month that the capacity in regard to persons is reasonably well developed, and in a minority it lags some weeks behind that. For reasons to do with cognitive development, therefore, the types of response to separation with which we are concerned could hardly be expected in infants younger than those in whom they are seen.
Change after the First Birthday
All the evidence suggests that, once established, the typical patterns of response to being placed in strange surroundings
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with strange people do not undergo marked change, either in form or in intensity, much before the third birthday. Thenceforward their intensity begins to diminish, but only slowly. As an example, the change in Lottie's feelings about going to nursery school that appeared at the beginning of the third term, when she was aged two years and nine months (see above, p. 38 ), is characteristic of many children. Provided he knows where his mother is and has good reason to expect her to return soon, a child begins to accept another fairly familiar person, even when he is in a fairly unfamiliar place.
The only conditions at present known that reduce appreciably the effects of separation from mother are familiar possessions, the companionship of another and familiar child and, as Robertson & Robertson ( 1971) have shown, especially mothering from a skilled and familiar foster mother. By contrast, strange people, strange places, and strange proceedings are always alarming; and they are especially alarming when encountered alone (see Chapters 7 and 8). ?
Since distress at being separated unwillingly from an attachment figure is an indissoluble part of being attached to someone, changes occurring with age in the form of response to separation accompany, step by step, changes in the form that attachment behaviour takes. These changes are sketched in the first volume (Chapters 11 and 17) and need not be described further here. In so far as attachments to loved figures are an integral part of our lives, a potential to feel distress on separation from them and anxiety at the prospect of separation is so also. That is a theme running through the rest of this volume.
Meanwhile, in order that we may view the responses to separation seen in humans in a perspective broader than has been traditional, it is useful to compare the responses of young human children with those of the young of other species. When that is done it becomes evident that, just as attachment behaviour occurs in rather similar forms across a number of mammalian and avian species, so also do responses to separation. Here again man is no isolated case.
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Chapter 4
Behaviour with and without Mother: Non-human Primates
Man with all his noble qualities, with sympathy that feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system -- with all these exalted powers -- still bears in his bodily frame the indelible stamp of his lowly origin.
CHARLES DARWIN ( 1871)
Naturalistic observations
It has long been known that isolation and separation from a mother figure can cause distress, expressed in calling and searching, in the young of many species of bird and mammal. The 'lost piping' of young ducklings who have become attached to and have temporarily lost a mother figure is a familiar example. Others are the bleating of lambs and the yelping of puppies. Coming nearer man, there are numerous examples in the accounts of monkey and ape infants brought up by human caretakers. All accounts agree on the intensity of protest exhibited whenever a baby primate loses its mother figure, and the intensity of distress that follows when she cannot be found. All agree, too, on the intensity of clinging that occurs after the two are reunited.
For example, Bolwig ( 1963), in his account of the little patas monkey he reared from a few days old,1 describes how from the first the little monkey 'showed no fear of man, cried much, and panicked when left alone. . . . The screaming, with wide open mouth and distorted face, was only heard when the observer moved out of the monkey's immediate reach or sight. On such occasions he would more often than not run staggering to the nearest person in sight. ' Soon the monkey's attachment had become focused on Bolwig himself and then, until three and a
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1 See Volume I, Chapter 11.
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half months of age, the monkey could be very troublesome unless perpetually with his caretaker.
By the age of four months, however, the little monkey was exploring increasingly far afield and his master decided
to leave him for some hours every day in a cage with other monkeys of his own kind. This attempt was, however, not very successful. Although he knew the other monkeys well and was accustomed to play with them he panicked as soon as he knew I wanted to leave him
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behind, screamed, clung desperately to me and then tried to tear the door open. He would sit and cry until I finally let him out. Afterwards he would cling to me and refuse to leave me out of sight for the rest of the day. In the evening when asleep he would wake up with small shrieks and cling to me, showing all signs of terror when I tried to release his grip.
Accounts of similar behaviour are given of infant chimpanzees. Cathy Hayes ( 1951) recounts how Viki, a female she adopted at three days, would, when aged four months, cling to her foster mother
from the moment she left her crib until she was tucked in at night. . . . She sat on my lap while I ate or studied. She straddled my hip as I cooked. If she were on the floor, and I started to get away, she screamed and clung to my leg until I picked her up. . . . If some rare lack of vigilance on her part let a room's length separate us, she came charging across the abyss, screaming at the height of her considerable ability.
The Kelloggs, who did not adopt their female chimp, Gua, until she was seven months old and who kept her for nine months, report identical behaviour ( Kellogg & Kellogg 1933). They describe
an intensive and tenacious impulse to remain within sight and call of some friend, guardian, or protector. Throughout the entire nine months . . . whether indoors or out, she almost never roamed very far from someone she knew. To shut her up in a room by herself, or to walk away faster than she could run, and to leave her behind, proved, as well as we could judge, to be the most awful punishment that could possibly be inflicted. She could not be alone apparently without suffering.
Comparing Gua with their son, who was two and a half months older than she, the Kelloggs report:
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Both subjects displayed what might be called anxious behaviour (i. e. fretting and crying) if obvious preparations were being made by the grown-ups to leave the house. This led (in Gua) to an early understanding of the mechanism of door closing and a keen and continual observation of the doors in her vicinity. If she happened to be on one side of a doorway, and her friends on the other, the slightest movement of the door toward closing, whether produced by human hands or by the wind, would bring Gua rushing through the narrowing aperture, crying as she came.
The very detailed observations made by van Lawick-Goodall ( 1968) of chimpanzees in the Gombe Stream Reserve in central Africa show not only that anxious and distressed behaviour on being separated, as reported of animals in captivity, occurs also in the wild but that distress at separation continues throughout chimpanzee childhood. During the first year an infant is rarely out of actual contact with mother and, although from its first birthday onwards it spends more time out of contact, it none the less remains in proximity to her. Not until young are four and a half years of age are any of them seen travelling not in the company of mother, and then only rarely. 1
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Once an infant begins to spend time out of contact with mother, proximity is maintained largely by auditory signals. Either mother or infant emits a 'hoo' whimper to which the other promptly responds:
When the infant . . . begins to move from its mother, it invariably utters this sound if it gets into any difficulty and cannot quickly return to her. Until the infant's locomotor patterns are fairly well developed the mother normally responds by going to fetch it at once. The same sound is used by the mother when she reaches to remove her infant from some potentially dangerous situation or even, on occasion, as she gestures it to cling on when she is ready to go. The 'hoo' whimper therefore serves as a fairly specific signal in re-establishing mother-- infant contact.
Another signal used by infants is a scream; it is elicited whenever an infant falls or nearly falls from its mother or is frightened by a sudden loud noise. When her infant screams a mother almost unfailingly retrieves it and cradles it: 'On several occasions
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1 For a brief description of the developmental course of attachment behaviour in
chimpanzees see Volume I. Chanter 11. -59-
infants screamed loudly when their mothers started to move away without them. Each time the mothers immediately turned back and retrieved them. Indeed, throughout infancy, screaming normally results in the mother hurrying to rescue her child. '
Juveniles up to five or six years old also scream when lost or in trouble, and again mother usually hurries to the rescue:
On several occasions juveniles were observed who had accidentally lost their mothers. In each instance, after peering round from various trees, whimpering and screaming as they did so, they hurried off -- often in the wrong direction. On three occasions I was able to observe the reaction of the mother and every time, although she set off in the direction of her offspring's screaming, she herself made no sound to indicate her whereabouts.
In one case a juvenile female aged five years lost her mother in the evening and was still whimpering and crying the following morning. In another case, a juvenile stopped screaming before her mother found her, which resulted in a separation lasting several hours. (No information is available regarding behaviour of the young after reunion. )
Thus in these wild-living chimpanzees proximity of young to mother is maintained until pre- adolescence. Separations are rare, and usually quickly rectified by vocal signals and mutual search.
Early experimental studies
These naturalistic accounts show plainly not only that the attachment behaviour of young non- human primates is very similar to the attachment behaviour of young children but that their responses to separation are very similar also. Because of this, and because experimental separations lasting longer than minutes are inadmissible in the case of human young, more
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than one scientist has turned to monkey young for experimental subjects. A number of studies from at least four different centres are now published.
