The interplay of cortical magnification and perceptual load in the visual processing of task-irrelevant biological motion across the visual field

Perceptual load theory argues that attention is a limited resource and stimuli cannot be processed if there is insufficient perceptual capacity available. Although attention is known to modulate biological motion processing, whether this modulation differs among different perceptual loads remains unknown. To answer this question, three experiments are conducted in which biological motion is utilized as a task-irrelevant distractor. The first experiment showed that biological motion is processed differently than non-biological motion across different perceptual load conditions. The second experiment investigated the effect of attention on biological motion processing, revealing that higher eccentricities enhance biological motion processing but only when the perceptual load is low. The last experiment investigated the same question but with cortically magnified stimuli. It found that when the stimuli are cortically magnified, the enhancement effect of eccentricity is present regardless of the perceptual load. Overall, the results suggest that perceptual load modulates the processing of task-irrelevant biological motion and interacts with other factors (such as eccentricity) that modulate this processing.