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A new study shows that although 14-month-olds infants can imitate a novel means action modelled to them, they do so only if they consider the action as the most rational alternative to the goal available. This indicates that imitation of goal-directed action is a selective interpretative process rather than automatically triggered by the movement observed (nature, February 14, 2002).
Nature reports about an astonishing experimental finding of the developmental psychologists György Gergely and Ildikó Király from the Institute for Psychology of the Hungarian Academy of Sciences, Budapest, Hungary and the cognitive psychologist Harold Bekkering from the Max Planck Institute for Psychological Research in Munich, now at the department of Experimental and Work Psychology in Groningen, the Netherlands. Starting point for the investigation was Meltzoff's seminal study in which 14-month-olds observed a model illuminate a box by leaning forward and touching its top panel with her forehead.1,2 After a week, 67% of infants re-enacted this novel 'head-action', while no infant performed it spontaneously in a base-line control group. Meltzoff argued that infants differentiate the goal from the means and "imitate the means…, not solely the…ends" (p. 509).2 Tomasello proposed that such imitative learning is human-specific as primates don't imitate novel means: they try to bring about the outcome by performing motor actions already in their repertoire (emulation).3 If infants used emulation, one would expect them to simply touch the box with their hand, instead of imitating the unfamiliar 'head-action'.3 (Meltzoff, however, did not report such 'hand-actions'.1,2)
So why re-enacted the infants in Meltzoff's study the novel 'head-action', when they could have simply touched the box with their hands? We hypothesised that Meltzoff's situation contained features that allowed infants to 'rationalise' the 'head-action': they may have interpreted the fact that even though the model's hands were free, she didn't use them, but touched the box with her forehead instead. They may have concluded that the 'head-action' must have some advantage in achieving the goal and so, when in the same situation, they re-enacted it themselves.4,5
To test this we replicated Meltzoff's study1 with one modification: in one condition ('Hands-occupied') the model's hands were visibly occupied while performing the 'head-action' (she, pretending to be chilly, wrapped a blanket around her holding it with both hands). In the 'Hands-free' condition (where the model acted the same way, but left her hands visibly free, see also Figure 1) 69% of infants re-enacted the 'head-action', replicating Meltzoff1. In the 'Hands-occupied' condition, however, imitation of the 'head-action' dropped significantly to only 21% (p<.02). Thus, while it seemed sensible that the model with hands occupied performed the 'head-action', 79% of infants didn't imitate this, as for them, whose hands were free, it didn't appear to be the most rational means available.
Furthermore, the scientists found that, whether they re-enacted the 'head-action' or not, all infants in both conditions performed the 'hand-action'. This suggests that 14-month-olds are still subject to an automatic emulation-like process whereby the memory of the effect (illumination upon con-tact) activates the response most strongly associated with establishing contact (hand-action). However, the fact that the novel 'head-action' - when inferred rational for the infant - was re-enacted, indicates that the imitative performance of 14-month-olds goes beyond emulation. We conclude that early imitation of goal-directed actions is a selective inferential process involving the evaluation of rationality of means in relation to situational constraints.6
1. Meltzoff, A. N. (1988). Infant imitation after a 1-week-delay: Long term memory for novel acts and multiple stimuli. Developmental Psychology, 24, 470-476.
2. Meltzoff, A. N. (1995). What infant memory tells us About infantile amnesia: Long term recall and deferred Imitation. Journal of Experimental Child Psychology, 59, 497-515.
3. Tomasello, M. (1999). The Cultural Origins of Human Cognition. Cambridge, MA: Harvard University Press
4. Gergely, G., Nádasdy, Z., Csibra, G., & Bíró, S. (1995). Taking the intentional stance at 12 months of age. Cognition, 56, 165-193.
5. Csibra, G., Gergely, G, Bíró, S., Koós, O., & Brockbank, M. (1999). Goal attribution without agency cues: the perception of 'pure reason' in infancy. Cognition, 72, 237-267.
6. Bekkering, H., Wohlschläger, A., & Gattis, M. (2000). Imitation is goal-directed. Quarterly Journal of Experimental Psychology, 53A, 153-64.
Journal
Nature