From action perception to imitation: Children and adults use action features to determine whether an observed action is (un)necessary

Abstract

Children and adults often learn through imitation, sometimes even reproducing actions that are unnecessary for achieving an instrumental goal. This phenomenon, known as over-imitation, can reflect social (affiliative or normative) motives but also mistaken causal beliefs. Only the former requires recognition that an action is unnecessary for achieving the instrumental goal. To discern between social and causal motives for over-imitation, it is therefore important to understand how individuals determine whether an action is functionally necessary or unnecessary. In two eye-tracking studies, we examined how urban German children (n = 48) and adults (n = 47) use action features to judge whether an action is causally necessary or unnecessary for achieving a goal. We found that both age groups struggled to recognize pseudoinstrumental actions—unnecessary actions that involve physical contact with the object and thus seem causally plausible at first sight—as unnecessary, relative to ritualistic actions, which involve no such contact. Children copied pseudo-instrumental actions more frequently than adults, suggesting that adults may invest more cognitive effort into evaluating the causal relevance of an action. With increasing age, over-imitation thus appears to become more selective and deliberate.