Abstract
Perception is necessarily constrained by underlying psychophysical thresholds. This is most obvious when considering the perception of low-level visual features, such as motion: certain rates of change (as in the moving second hand on a clock) result in vivid impressions of motion, while others (such as the moving minute hand) do not. What we see often transcends such basic properties, however: when viewing the movements of objects, we may also have vivid impressions of seemingly high-level properties such as causality or animacy. It has been argued that such properties are also extracted during relatively early and automatic visual processing itself, but are they also constrained in the same ways? In particular, does the perception of such properties simply inherit the psychophysical thresholds of lower-level motion perception? Or might they operate according to their own domain-specific limits? We explored this in the context of several seemingly high-level visual properties, one of which is perhaps the most direct example of perceiving ‘minds from motion’: the perception of *chasing*. Observers viewed displays with many moving discs, of which one (the ‘wolf’) was pursuing another (the ‘sheep’) with some degree of directedness (or ‘chasing subtlety’). Previous work revealed that such chasing is often detected highly efficiently, but how does this ability scale with speed? We discovered that the perception of chasing is degraded to a surprising degree when the objects move slowly, yet still very far above familiar motion thresholds. This was true when we equated both overall display durations across speeds (with shorter trajectories for slower objects), and overall trajectories across speeds (with longer animations for slower objects). These results (along with other manipulations of perceived causality and intentionality) show how higher-level properties are perceived according to their own domain-specific psychophysical limits — and they emphasize the utility of exploring ‘slow visual cognition’.