Читать книгу The Wiley-Blackwell Handbook of Childhood Social Development - Группа авторов - Страница 77

At the beginning of the 21st century, in January 2000, two developmentalists who had long sought to bring evolutionary theory into child development, David Geary and David Bjorklund, decided the time was right to produce a formal definition of the emerging interdisciplinary field of evolutionary developmental psychology. They defined it as:

the study of the genetic and ecological mechanisms that govern the development of social and cognitive competencies common to all human beings and the epigenetic (gene environment interactions) processes that adapt these competencies to local conditions.

(Geary & Bjorklund, 2000, p. 57)

Geary and Bjorklund pointed out that seemingly immature behavioral patterns should really be seen as adaptive responses designed by selection forces to increase parental investment and aid survival. An example of this is the fact that children spend so much of their time engaged in social play. This apparently pointless behavior allows for the development of appropriate social responses and a knowledge of the child’s likely later social standing (Pellegrini & Smith, 1998; Smith, 1982; and Chapter 28, this volume). Likewise, stranger and separation anxiety both lead to the child seeking protection from the caregiver at a point when they are particularly vulnerable (that is, during infancy and childhood, a period when they have become relatively mobile but are still too small to protect themselves). Interestingly, these forms of anxiety emerge at the same age not only across human cultures but also at approximately the same point in physical development in chimpanzees. Geary and Bjorklund take this as strong evidence that these forms of social anxiety have a long evolutionary history.

Building on earlier work by Geary (1995), they also suggested that child capabilities can be divided into biologically primary and secondary abilities. Biologically primary abilities evolved to deal with ancient recurrent cognitive and social challenges, whereas secondary abilities are those that are culturally determined. Hence, the primary abilities are likely to develop with ease via epigenetic processes. These include the development of spoken language and general sex differences in play behavior (for example, boys engaging more in rough‐and‐tumble play and girls more in cooperative fantasy play). Biologically secondary abilities are unnatural when seen in the light of our species EEAs. Examples of these include written language and formal mathematics. According to Geary and Bjorklund this means that, while children are motivated to acquire primary abilities (and they come relatively easily), secondary abilities are arduous and perceived as tediously repetitive.

While Geary and Bjorklund have frequently collaborated, much of their work has been conducted within their own research teams. During the last 20 years Bjorklund and his team have suggested there are three types of developmental adaptations: Ontogenetic adaptations; Deferred adaptations; and Conditional adaptations.

Looking briefly at each of these in turn, ontogenetic adaptations evolved to help the child survive at a specific point in development, but disappear when no longer required. Examples of this include neonatal imitation, milk teeth, and fear of strangers (Myers & Bjorklund, 2020; Workman & Reader, 2021). Notably, ontogenetic adaptations include various aspects of cognitive immaturity. An example of this is that children regularly overestimate their own abilities. The suggestion here is that, if children understood how poorly they actually performed on many tasks they would most likely give up at an early stage. In one study, for example, Shin et al. (2007) found first‐grade children who overestimated their performance on memory trials later showed greater improvement on memory tasks than those who did not overestimate this ability. Hence, this overestimation of ability can later lead to improvements in ability. Myers and Bjorklund (2020) suggest there may be a whole raft of such social and cognitive ontogenetic adaptations that are appropriate for that age, but which then disappear.

Deferred adaptations are those which have no immediate benefit but are useful later in development. Social and object play are good examples of this. Many social skills are learned through engaging in play with others. Such skills are put to good use later in life in order to negotiate the social landscape. Many would suggest that infants and young children play together because it is enjoyable and leads to immediate gratification. But the ultimate reason why it is enjoyable, according to evolutionists such as Geary and Bjorklund, is because ancestral children who found it to be rewarding reaped the benefits later in life and passed on this proclivity to their offspring.

Finally, conditional adaptations can be seen as a special case of deferred adaptations in that they are environmentally conditional. This means that, given an unpredictable environment, it pays children to later be able to alter their developmental trajectory (up to a point: Barkow, 1989). In the case of sexual maturation, those under harsh conditions might leave more surviving offspring by developing to sexual maturity earlier. Note that this is part‐and‐parcel of Belsky’s conception of LH theory. In fact, all three of these types of developmental adaptations are conducive with an LH approach to understanding the relationship between evolution and development. Overall, it is fair to say that LH theory has provided a useful framework for understating the relationship between social development and evolutionary theory.