Predictive processing in biological motion perception: Evidence from human behavior.

Biological motion perception plays a crucial role in understanding the actions of other animals, facilitating effective social interactions. Although traditionally viewed as a bottom-up driven process, recent research suggests that top-down mechanisms, including attention and expectation, significantly influence biological motion perception at all levels, particularly highlighted under complex or ambiguous conditions. In this study, we investigated the effect of expectation on biological motion perception using a cued individuation task with point-light display (PLD) stimuli. We conducted three experiments investigating how prior information regarding action, emotion, and gender of PLD stimuli modulates perceptual processing. We observed a statistically significant congruency effect when preceding cues informed about action of the upcoming biological motion stimulus; participants performed slower in incongruent trials compared to congruent trials. This effect seems to be mainly driven from the 75% congruency condition compared to the non-informative 50% (chance level) validity condition. The congruency effect that was observed in the action experiment was absent in the emotion and gender experiments. These findings highlight the nuanced role of prior information in biological motion perception, particularly emphasizing that action-related cues, when moderately reliable, can influence biological motion perception. Our results are in line with the predictive processing framework, suggesting that the integration of top-down and bottom-up processes is context-dependent and influenced by the nature of prior information. Our results also emphasize the need to develop more comprehensive frameworks that incorporate naturalistic, complex and dynamic, stimuli to build better models of biological motion perception.