Hong B Nguyen¹ (), Benjamin van Buren¹; ¹The New School

We often see others’ behaviors as reflecting underlying mental states, such as beliefs and desires. Perceiving behavior as goal-directed may be computationally efficient: For example, when predicting whether your friend will walk to a store to buy eggs, it is simpler to do so in terms of their beliefs and desires than in terms of the complex physical forces causing their movements. Or, when predicting the orientation of a moving dart, it is simpler to predict that it will continuously turn in order to face another moving shape than to extrapolate its current angular acceleration. Computational efficiency provides a good in-principle argument for why we should see others’ behavior as goal-directed—but this account has rarely (if ever) been tested. To investigate this, we measured whether displays featuring goal-directed movement produce a well-established signature of visual processing fluency—positive *hedonic* responses. In 10 experiments, observers viewed a moving shape (a dart, or an ellipse) which updated its orientation to face or remain aligned with a moving disc, producing a strong impression of intentionality. They also viewed closely-matched inanimate control displays (e.g. in which the shape moved identically, but updated its orientation to face away from the disc, or remain offset by 30°). Observers consistently preferred displays featuring goal-directed motion—and this result was mirrored in 10 further experiments measuring implicit associations. These experiments rule out low-level explanations (such as symmetry), and show that the preference to see goal-directed movement is not just a preference for more animate-looking displays, as goal-directed shapes were also preferred to those which looked animate but not strongly goal-directed (e.g. randomly moving darts which faced where they were heading, producing an impression of ‘aimless’ movement). These results suggest that seeing simple shapes in goal-directed terms allows us to efficiently predict their behavior, which in turn drives positive affective responses.