Proceedings of the Annual Meeting of the Cognitive Science Society

Humans often communicate through seemingly arbitraryactions, like winks, waves, and nods. While these non-iconicgestures derive their meanings from cultural consensus,people, and especially children, must be able to identify thesemovements as gestures. Here we propose that people expectthat communicative actions will be shaped to reveal that theyhave no external goal. In Experiment 1, we show that peoplejudge inefficient actions as more likely to be communicative.In Experiment 2, we show that these judgments are trulydriven by efficiency, rather than a movement’s visualcomplexity. Finally, in Experiment 3, we show that repetition– which unambiguously reveals that the goal of the action isthe movement itself – has a strong influence on inferencesabout communicativeness, independent of the motion’sefficiency. Our findings show how expectations about non-iconic communicative actions can be folded into a generalgoal inference framework structured around an expectationfor efficiency.