§2-7. Attachments of Infants and Animals

"We want to make a machine that will be proud of us." -- Danny Hillis, 1983

The young child Carol loves to explore, but also likes to stay near to her mother—so whenever the distance between them grows, she quickly moves herself closer. But should she discover that she is alone, she'll shortly cry out and look for her mum. That same behavior will also appear even when her mother is near, if there’s any cause for fear or alarm—such as the approach of a stranger.

Naturally, this dependency stems from our infantile helplessness: no human infant would long survive if it could escape from parental care. Of course, this doesn’t happen because young infants cannot move much by themselves—but this comes with the disadvantage that, in those first few months, our infants also can’t follow their mothers. Fortunately we usually come to no harm from this because we evolve a second bond that goes in the other direction: Carol’s mother is almost always aware (to different extents at various times) of what is happening to her daughter—and her full attention is quickly engaged at the slightest suspicion that something is wrong.

Clearly, each infant’s survival depends on bonding to persons concerned with their welfare. So in older times it was often assumed that children would attach themselves to the persons who gave them physical care, and this is why most psychologists called such a person a 'Caregiver'—instead of using some word like ‘Imprimer’. But more systematic research on attachment suggested that this theory was wrong:

John Bowlby: “That an infant can become attached to others of the same age, or only a little older, makes it plain that attachment behavior can develop and be directed towards [persons who have] done nothing to meet the infant's physiological needs.” [5]

Then what factors do determine the persons to whom our children will become attached? First, Bowlby recognized that physical nurture could play an important role, because it provides occasions for children to learn to like to be with particular other persons. But eventually he concluded that usually, these were more important factors: [6]

The speed with which the person responds, and The intensity of that interaction.”

This will usually include the child’s parents—but could also include other children, which suggests that parents should take special care to examine their offspring's companions and friends—and, especially, the ones that are most attentive to them. And when one is choosing a child's school, one might examine not only the staff and curriculum, but also the goals that its pupils pursue.

What happens when a child is deprived of Imprimers? It appears that an Imprimer's absence produces a special variety of fear, and a powerful impulse to find that Imprimer.

John Bowlby: “Whenever a young child … is separated from her mother unwillingly he shows distress; and should he also be placed in a strange environment and cared for by a succession of strange people such distress is likely to be intense. The way he behaves follows a typical sequence. At first he protests vigorously and tries by all the means available to him to recover his mother. Later he seems to despair of recovering her but nonetheless remains preoccupied with her and vigilant for her return. Later still he seems to lose his interest in his mother and to become emotionally detached from her.”

Bowlby goes on to describe what happens when the mother comes back:

“Nevertheless, provided the period of separation is not too prolonged, a child does not remain detached indefinitely. Sooner or later after being reunited with his mother his attachment to her emerges afresh. Thenceforward, for days or weeks, and sometimes for much longer, he insists on staying close to her. Furthermore, whenever he suspects he will lose her again he exhibits acute anxiety.”[7]

We see similar attachment behavior in our various primate relatives—such as chimpanzees, gorillas, and orangutans—as well as in our more distant cousins, the monkeys. We should also note Harry Harlow’s discovery that, given no other alternative, a monkey will become attached to an object that has no behavior at all, but does have some 'comforting' characteristics. This would seem to confirm Bowlby’s view that attachment does not stem from ‘physiological needs’—unless we amend this to include the infant’s need for what Harlow calls comfort contact. [8]

John Bowlby: “The very detailed observations made by Jane Goodall of chimpanzees in the Gombe Stream Reserve in central Africa show not only that anxious and distressed behavior on being separated, as reported of animals in captivity, occurs also in the wild but that distress at separation continues throughout chimpanzee childhood. … Not until young are four and a half years of age are any of them seen traveling not in the company of mother, and then only rarely.” — [John Bowlby, p. 59 Separation.]

When the mother and child have more distance between them, they maintain their connection with a special 'hoo’ whimper to which the other promptly responds—as Jane Goodall herself reports:

“When the infant return to her. Until the infant's locomotion 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.” [9]

What happens in other animals? Early in the 1930s Konrad Lorenz observed that a recently hatched chicken, duck, or goose will become “attached” to the first large moving object it sees, and will subsequently follow that object around. He called this “imprinting” because it occurs with such remarkable speed and permanence. Here are some of his observations. [10]

The chick quickly starts to follow the moving object. Imprinting begins soon after hatching. The period for imprinting ends a few hours later. The effect of imprinting is permanent.

To what objects will the chick get attached? That moving object will usually be a parent—but if the parents have been removed, then the object could be a cardboard box, or a red balloon—or even Konrad Lorenz himself. During the next two days, as the gosling follows its parents, it somehow learns to recognize them as individuals and not follow any other geese. Now when it loses contact with the mother it will cease to feed or examine things, and instead will search and make piping sounds, as though distressed at being lost. Then the parent responds with a special sound—and Lorenz observes that this response must come quickly to establish imprinting. Later this call is no longer needed, but in the meantime it serves to protect the chick against becoming attached to an unsuitable object, such as the moving branch of a tree.

These 'piping' sounds, like the ‘hoo’ signals in Jane Goodall’s notes, suggest that other ways to communicate could have co-evolved from attachment signals. In any case, these types of birds can feed themselves soon after they hatch—so imprinting is independent of being fed.

As for when the imprinting period ends, R.A.Hinde discovered that those chicks eventually become fearful of unfamiliar moving things—which led him to suspect that imprinting stops when this new fear forestalls further 'following'. Similarly, many human babies show a long period of fear of strangers that begins near the start of the second year.[11]

Bowlby’s research on young children showed that when they are deprived of imprimers for more than a few days, they may show signs of impairments for much longer times. He also cites similar results when other researchers separated infant Rhesus monkeys from their mothers:

“From all these findings[12] we can conclude with confidence not only that a single separation of no longer than six days at six months of age has perceptible effects two years later on rhesus infants, but that the effects of a separation are proportionate to its length. A thirteen-day separation is worse than a six-day; two six-day separations are worse than a single six-day separation.”— Bowlby, in Separation, p72

Remarkably, even badly mistreated children (and monkeys) may remain attached to abusive imprimer.[13]

To what extent did human attachment-based learning evolve from older forms of pre-human imprinting? Of course, humans are very different from birds, yet the infants of both share similar needs—and there may have been precursors of this in some earlier warm-blooded dinosaurs. For example, Jack Horner[14] discovered that some of these constructed clusters of bird-nest like structures. Further progress in genomics might help us reconstruct more of this history.

Returning to the human realm, we should ask how infants distinguish potential imprimers. Although some researchers have reported that infants can learn to recognize the mother’s voice even before the time of birth, it is generally though that newborns first learn mainly through the senses of touch, taste, and smell—and later distinguish the sound of a voice and start to react to the sight of a head or a face. One first might assume that this is done by detecting features like eyes, nose, and mouth, but there is evidence that it is more complex than that.[15]

Francesca Acerra: "4-day-old neonates look longer at their mother's face than at a stranger's face—but not when the mother wears a scarf that hides the hair contour and the outer contour of the head.”[16]

This researcher found that those infants react less to the features of the face, and more to its larger-scale, overall shape; it was not until two or three more months that her subjects distinguished particular faces.[17] This suggests that our visual systems involve different methods at different stages of development—and perhaps the ones that are first to operate serve mainly to get the mother attached to the child! In any case, Lorenz was amazed by what his goslings failed to distinguish:

Konrad Lorenz: “The human imprinted gosling will unequivocally refuse to follow a goose instead of a human, but it will not differentiate between a petite, slender young girl and a big old man with a beard. … It is astounding that a bird reared by, and imprinted to, a human being should direct its behavior patterns not towards one human but towards the species Homo sapiens.”[18]

I don’t find this so strange because all geese look almost the same to me. Perhaps more important is that adult sexual preference may be established at this early time, though it only much later appears in behavior.

“A jackdaw for which the human has replaced the parental companion, will thus direct its awakening sexual instincts not specifically towards its former parental companion, but … towards any one relatively unfamiliar human being. The sex is unimportant, but the object will quite definitely be human. It would seem that the former parental companion is simply not considered as a possible 'mate'.”

Some studies have shown that after such contact, some of those birds will eventually mate with other members of their species. However, this phenomenon is still such a serious problem in repopulating endangered species that it has become the standard policy to minimize human contact with chicks, lest their preference for people lead them to later refuse to mate with their peers. Could such delays be relevant to human sexual preferences?

All of this could help to explain why we evolved our extended infantile helplessness: children who too soon went off by themselves would not have been wise enough to survive—and so, we had to extend the time for learning from imprimers instead of from doing risky experiments.