What is the effect of early parenting on a child's social and emotional development? Does a child's relationship to a caregiver set a pattern of social relationships that holds throughout life? A variety of answers have been give to these questions. For a long time, the kinds of psychodynamic approaches described in the previous section dominated researchers' understanding of very early social relationships. In the 1940s and 1950s, however, research in animals and in human orphans showed that early social development could be understood much more simply. Researchers such as Harlow, Bowlby, Ainsworth, Erikson, and others argued that children have a need for caring social relationships, and that it is the presence and quality of such relationships--not the complicated internal dynamics postulated by Freud--that shape the child's social and emotional development.

In the 1950's, Harry Harlow conducted a series of experiments on rhesus monkeys showing that comfort and social interaction were important to survival. In some studies, infant monkeys were raised in complete isolation. They received food and water, and their cages were kept clean and warm, but nonetheless they became extremely fearful, depressed, and unable to gain acceptance among other monkeys when they were finally brought out of isolation. In other studies, infant monkeys were raised with "surrogate" mothers: wire and cloth contraptions that were meant to resemble the monkeys' mothers. What Harlow found was that monkeys were much more likely to treat a soft cloth surrogate mother as they would a real mother--a source of comfort and security--than a wire surrogate mother, even when the wire surrogate was the monkeys' only source of food. This was taken as evidence that infant primates have an innate need for physical comforting.

At the same time that Harlow was conducting his monkey experiments, John Bowlby was developing his theory of infant attachment. Bowlby's theory was influenced both by psychodynamic theories and by ethological research. He claimed that children's need for a comforting, secure adult figure was evolutionarily advantageous since it helped prevent the child from entering into dangerous situations. Thus children have an innate need for a caregiver: they become distressed in the caregiver's absence and comforted upon the caregiver's return, and they are more active and exploratory when the caregiver is present than when he or she is not.

Mary Ainsworth, who worked with Bowlby, translated his theory into an experimental paradigm called the Strange-Situation Test. In this test, the infant is brought into a room with toys. The infant's mother and a stranger enter and exit the room in a pre- specified sequence, and the child's reactions (e.g. crying, exploration, rapidity of comforting by the mother) to each change are measured. Ainsworth developed a scheme to distinguish different types of children based on the results of the Strange-Situation Test. Children who become upset in the absence of the mother but are quickly comforted when the mother returns are called "securely attached." Children who avoid the mother or seem to resent her upon her return, who are not easily comforted or are not exploratory even in the mother's presence, are labeled "insecurely attached." Insecurely attached infants can be subdivided into "avoidant" or "resistant." Further subdivisions in Ainsworth's scheme have also been made. Secure attachment appears to be a good predictor of later personality measurements such as self-esteem, confidence, positive social relations, etc.