Communicating Through Acting: Affording Communicative Intention in Pantomimes

How do people intuitively recognize communicative intention in pantomimes, even though such actions kinematically resemble instrumental behaviors directed at changing the world? We focus on two alternative hypotheses: one posits that instrumental intention competes with communicative intention, such that the weaker the former, the stronger the latter; the other suggests that instrumental intention is nested within communicative intention, such that the presence of the former facilitates the latter. To test these hypotheses, we compiled a video dataset of action-object pairs with varying frequencies in the English corpus. Using the concept of affordance, we qualitatively varied the degree to which a scene visually supports the execution of an action. Across two empirical experiments, we found a nonmonotonic relationship between affordance and communicative ratings: partial affordance, where the scene provides some support for an action's instrumental purpose, elicited the strongest perception of communicative intention. In contrast, full affordance or no affordance resulted in weaker interpretations of communicative intention. We also found that recognizing the instrumental components of pantomime-like actions predicted a higher communicativeness rating. Our study, on top of confirming humans' ability to interpret novel pantomimes, reveals a novel mechanism of communicative intention: recognizing an instrumental goal and perceiving suboptimal conditions for achieving it together enhance the communicative signal. This work contributes toward an integrated theory of pantomimes, demonstrating how the rationality principle not only aids in distinguishing communicative intention but also supports the identification of instrumental content embedded within it.