Thinking and talking are—to use a term introduced in Chapter 3—species-typical activities of humans. We are biologically predisposed for thought and language, just as we are predisposed to smile and walk on two legs. The human brain has been specialized for these activities in the course of evolution; people everywhere, in every culture, think and talk in ways that are recognizably human and distinguishable from the activities of any other species. Yet, despite their universality, these abilities must develop anew in each human being.
1. Why thought and language must develop Why aren’t these species-typical abilities fully present at birth? An immediate answer is that birth occurs in humans at a relatively early stage in the body’s growth. The brain, including the pathways required for thought and language, continues to mature after birth. A more profound answer, however, lies in the ultimate functions of thought and language.
Thought serves to make sense of the environment so that we can navigate safely through it and use parts of it to promote our survival and reproduction. We can survive in a wide range of conditions because we can think of ways to modify them to suit our needs. To do so, we must consider not just the universals of every environment, such as the fact that unsupported objects fall to the earth, but also the particulars of our specific environment, such as the foods that are available and the tools that are needed. Similarly, to communicate effectively in our particular cultural group, we must acquire the specific linguistic elements (the words and grammar) that have emerged in our group’s history and represent concepts that are crucial to survival in that group. That is, to be effective, thought and language must be fine-tuned to the unique physical and social environment in which each individual must survive, and such adjustment can be accomplished only when thought and language develop in that environment.
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2. Biological foundations for development Evolution could not endow human beings with the specific knowledge and skills needed to survive in every human environment, but it could and did endow the species with a solid foundation for acquiring them. This theme, of evolved and inherited foundations for development, can help you tie together many of the ideas and research findings that are described in this chapter. As you review, consider the following questions: What inborn assumptions may help each new person make sense of his or her physical, social, and linguistic worlds? What universal aspects of babies’ and children’s explorations and play may help them learn about the particulars of their native environments and languages?
The findings and ideas to which you can relate these questions include (a) infants’ preferences for novelty, their mode of examining objects, their drive to control their environment, and their knowledge of core physical principles; (b) Piaget’s ideas about the roles of action, assimilation, and accommodation in development, and other researchers’ theories about domainspecific development; (c) young children’s understanding of other people’s minds, their delayed understanding of false beliefs, the possible role of make-believe in acquiring that understanding, and the absence of such understanding in children with autism; (d) the roles of early attention to language, of vocal play, and of inborn biases and drives affecting vocabulary and grammar acquisition; and (e) Chomsky’s concept of a language-acquisition device and other researchers’ studies of children who invented language.
3. Social supports for development The inherited tendencies and drives that promote development are useless without a responsive environment. Babies need solid surfaces against which to exercise their muscles in order to learn to walk, objects to explore in order to learn about the physical world, and people to listen to and with whom to exercise their linguistic play in order to learn to talk. Young children may, as Piaget contended, choose what to assimilate from the smorgasbord of information around them, but adults help provide the smorgasbord.
As you review the chapter, consider the specific ways in which the child uses and is influenced by the social environment. In particular, consider (a) infants’ employment of gaze following, shared attention, and social referencing to guide their explorations; (b) Vygotsky’s theory of the roles of the tools of intellectual adaptation, dialogue, and cooperative action in the development of thought; and (c) the role of the language-acquisition support system in language development. In the next chapter, on the development of social relationships, you will read much more about ways in which variation in the social environment can influence development.