Infants learn enduring functions of novel tools from action demonstrations

According to recent theoretical proposals, one function of infant goal attribution is to support early social learning of artifact functions from instrumental actions, and one function of infant sensitivity to communication is to support early acquisition of generic knowledge about enduring, kind-relevant properties of the referents. The present study tested two hypotheses, derived from these proposals, about the conditions that facilitate the acquisition of enduring functions for novel tools in human infancy. Using a violation-of-expectation paradigm, we show that 13.5-months-old infants encode arbitrary end-states of action-sequences in relation to the novel tools employed to bring them about. These mappings are not formed if the same end states of action sequences cannot be interpreted as action goals. Moreover, the tool-goal mappings acquired from infant-directed communicative demonstrations are more resilient to counter-evidence than those acquired from non-infant-directed presentations, and thus show similarities to generic rather than episodic representations. These findings suggest that the acquisition of tool functions in infancy is guided by both teleological action interpretation mechanisms and the expectation that communicative demonstrations reveal enduring dispositional properties of tools.