In this paper I suggest that play is a distinctive behavioural category whose adaptive significance calls for explanation. Play primarily affords juveniles practice toward the exercise of later skills. Its benefits exceed its costs when sufficient practice would otherwise be unlikely or unsafe, as is particularly true with physical skills and socially competitive ones. Manipulative play with objects is a byproduct of increased intelligence, specifically selected for only in a few advanced primates, notably the chimpanzee.The adaptiveness of play in pongid (...) evolution is traced through the probable changes in selective pressures that occurred in hominid evolution. It is argued that fantasy was an emergent property in hominids, made possible by symbolic intelligence and language, and serving to make play complex enough to continue to provide useful practice for increasingly complex later skills.The advent of organised instruction and education has meant that play's unplanned, intrinisic goal-setting could be replaced by extrinsic goal-setting in the systematic development of particular skills. However, the need to ensure adequate motivation has continued to give play educational value. In addition, its capacity to enhance innovative behaviour seems to be a residual function of play which has acquired a new cultural importance. (shrink)

The Strange Situation procedure was developed by Ainsworth two decades agoas a means of assessing the security of infant-parent attachment. Users of the procedureclaim that it provides a way of determining whether the infant has developed species-appropriate adaptive behavior as a result of rearing in an evolutionary appropriate context, characterized by a sensitively responsive parent. Only when the parent behaves in the sensitive, species-appropriate fashion is the baby said to behave in the adaptive or secure fashion. Furthermore, when infants are (...) observed repeatedly in the Strange Situation,the pattern of behavior is said to be highly similar, and this pattern is said to predict the infants' future behavior in a diverse array of contexts. After an exhaustive review of the literature, it is shown that these popular claims are empirically unsupported in their strong form, and that the interpretations in terms of biological adaptationare misguided. There is little reliable evidence about the specific dimensions of parental behavior that affect Strange Situation behavior, although there does appear to be some relationship between these constructs. Temporal stability in security of attachment ishigh only when there is stability in family and caretaking circumstances. Likewise, patterns of Strange Situation behavior only have substantial predictive validity in similarly stable families. Implications for future research and theorizing — particularly as they relate to the use of evolutionary biology in psychological theory — are discussed. (shrink)