Infant-mother attachment.

Bowlby's (1969) ethological-evolutionary attachment theory implies that it is an essential part of the ground plan of the human species—as well as that of many other species—for an infant to become attached to a mother figure. This figure need not be the natural mother but can be anyone who plays the role of principal caregiver. This ground plan is fulfilled, except under extraordinary circumstances when the baby experiences too little interaction with any one caregiver to support the formation of an attachment. The literature on maternal deprivation describes some of these circumstances, but it cannot be reviewed here, except to note that research has not yet specified an acceptable minimum amount of interaction required for attachment formation. However, there have been substantial recent advances in the areas of individual differences in the way attachment behavior becomes organized, differential experiences associated with the various attachment patterns, and the value of such patterns in forecasting subsequent development. These advances have been much aided by a standardized laboratory situation that was devised to supplement a naturalistic, longitudinal investigation of the development of infant-mother attachment in the first year of life. This strange situation, as we entitled it, has proved to be an excellent basis for the assessment of such attachment in 1-year-olds (Ainsworth, Blehar, Waters, & Wall, 1978). The assessment procedure consists of classification according to the pattern of behavior shown in the strange situation, particularly in the episodes of reunion after separation. Eight patterns were identified, but I shall deal here only with the three main groups into which they fell—Groups A, B, and C. To summarize, Group B babies use their mothers as a secure base from which to explore in the preseparation episodes; their attachment behavior is greatly intensified by the separation episodes so that exploration diminishes and distress is likely; and in the reunion episodes they seek contact with, proximity to, or at least interaction