Over-imitation is better explained by norm learning than by distorted causal learning

Abstract

In over-imitation, children copy even elements of a goal-directed action sequence that appear unnecessary for achieving the goal. We demonstrate in 4-year olds that the unnecessary action is specifically associated with the goal, not generally associated with the apparatus. The unnecessary action is performed flexibly: 4-year olds usually omit it if it has already been performed by an adult. Most 5-year olds do not verbally report the unnecessary action as necessary when achieving the goal, although most of them report an equivalent but necessary action as necessary. Most 5-year olds explain the necessary action in functional terms, but are unsure as to the function of the unnecessary action. These verbal measures do not support the hypothesis that children over-imitate primarily because they encode unnecessary actions as causing the goal even in causally transparent systems. In a causally transparent system, explanations for over-imitation fitting the results are that children are ignorant of the unnecessary action's purpose, and that they learn a prescriptive norm that it should be carried out. In causally opaque systems, however, for children and for adults, any action performed before achieving the goal is likely to be inferred as causally necessary-this is not over-imitation, but ordinary causal learning.

Kinematic Measures of Imitation Fidelity in Primary School Children

“…Consequently, it is necessary to be interpret these findings in a context of the goaldirected imitation literature with some caution. In detecting a contraction bias, we find that children are imitating conservatively, which appears at some odds with literature suggesting that children are more likely to over-imitate (Horner & Whiten, 2005;McGuigan et al, 2010) and that they may do so to comply with prescriptive norms or cultural expectations (Kenward, Karlsson, & Persson, 2011;Nielsen & Blank, 2011). In our study however, the degree of error was not the result of intentional action selection but rather a mismatch between magnitudes of perceived and executed actions, presumably as a result of the functioning of the visuomotor system.…”

Putting the social into social learning: Explaining both selectivity and fidelity in children's copying behavior.

“…A subsequent study showed that children enforce norms learned in this way on ingroup members but not on outgroup members (Schmidt, Rakoczy, & Tomasello, submitted). Taken together, these studies show that in these kinds of situations, children not only learn the actions involved in the demonstration, they learn how members of their particular culture ought to perform the specified behavior (see also Kenward et al, 2011, for further evidence of the role of norms in imitation).…”

“…Lyons (2009) attempts to explain the existence of selective copying by arguing that actions not directed toward objects (e.g., those used in the Bekkering et al, 2000 study) may be copied selectively. However, this theory, along with the somewhat related theory of Kenward, Karlsson, and Persson (2011) that children learn a generalized norm that unnecessary actions ought to be performed, are brought into question by data demonstrating that some intentionally produced, objectdirected actions are imitated selectively. For example, in one demonstration of this, DiYanni and Kelemen (2008) presented 2-to 4-year-old children with a demonstration in which a model intentionally rejected a functionally affordant tool in favor of a nonaffordant tool.…”

The role of parietal cortex in overimitation: a study with fNIRS

“…Recent explanations of overimitation have focused on the social nature of this behavior, as a sign of social affiliation or conformity to a social norm (Kenward, Karlsson, & Persson, 2010;Marsh, Pearson, Ropar, & Hamilton, 2013). Social cues, such as demonstrator status, have been shown to modulate overimitation.…”