Derek E. Lyons: Post-Doctoral Scholar; UC Irvine Department of Informatics

Children are generally masterful imitators, both rational and flexible in their acquisition of knowledge from the observation of others. A phenomenon that we have termed overimitation (Lyons, Young, & Keil, 2007), however, initially seems a curious exception to this rule. After observing an adult intentionally operating an unfamiliar object with a sequence of relevant and irrelevant actions, children will frequently imitate not only the actions that were causally necessary, but also those that were clearly superfluous. Indeed, children will overimitate irrelevant actions that even chimpanzees readily ignore (Horner & Whiten, 2005). Prior explanations for overimitation tended to see it as a byproduct of social motivations (e.g. a desire to “be like” the adult or to accommodate inferred task demands), but we have argued that the phenomenon may have deeper significance. Our hypothesis is that when children observe an adult intentionally acting on a novel object, they may automatically encode all of the adult’s actions as causally meaningful, restructuring their causal beliefs about the object accordingly. This process of automatic causal encoding (ACE) would generally guide children to accurate beliefs about even highly opaque objects; however, in the case where some of the adults’ intentional actions were unnecessary, it would also lead to stubborn overimitation. In this talk I will undertake a thorough examination of the ACE hypothesis, reviewing prior evidence as well as offering three new experiments to further test the theory. Our new data show that children will persist in overimitating even when doing so imposes a direct and motivationally salient cost, thus underscoring the involuntary nature of the effect. At the same time, however, overimitation is not unbounded: the effect is strictly coupled to intentionality in a manner consistent with its posited learning function. Overimitation may offer an important window not only on the structure of children’s causal understanding, but also on the social learning processes that help to support our species’ artifact-centric culture.