In my last post I talked about Piaget's early research on children's causal reasoning. Much work has been done, of course, since Piaget's day. Based on her work with preverbal infants and young children, for example, developmental psychologist Alison Gopnik has argued that human beings possess something like an innate explanatory drive, motivating us to actively test out hypotheses concerning causal relations in the natural world.

Even if our theories are plain wrong, she suggests, we derive a distinct phenomenological feeling of explanatory pleasure (the "aha!" or "Eureka!" moments) whenever we're personally satisfied that that we've solved some cognitively irksome problem. Gopnik even goes so far as to claim that explanation does for human reasoning as sexual orgasm does for reproductive behavior, in that, in both cases, we're highly motivated to engage in that which feels good for the occasional adaptive benefits conferred. In the case of explanation, she says, understanding the natural world in veridical terms enabled our ancestors to better explain and to predict events, thus facilitating their adaptive decision-making. In fact, scientists who are intrinsically motivated to solve their complicated research problems, says Gopnik, are like big children, perpetually chasing after the explanatory highs so endemic to a curious childhood.

Comparative findings from studies with chimpanzees and young children seem to support Gopnik's general position that human beings are uniquely endowed with an innate explanatory drive. In one particularly informative study, cognitive scientists Daniel Povinelli and Sarah Dunphy-Lelii presented a group of laboratory chimpanzees and preschool-aged children with a simple task in which individuals from both species -- tested separately, of course -- were trained to place a pair of L-shaped blocks upright on a platform in order to receive a small reward (vanilla wafers and stickers, respectively).