The effect of the spatial distribution of attention on the perception of apparent motion

Apparent motion perception depends on both stimulus properties and attentional allocation, yet the role of the spatial distribution of attention remains unclear. The present study examined whether biases in attentional distribution systematically modulate bistable apparent motion perception. Using a motion quartet stimulus, three experiments manipulated attention along horizontal and vertical axes. In Experiments 1 and 2, attention was biased using elongated attentional cues. In Experiment 3, attention was manipulated via a secondary task while controlling for physical cue properties. Across all experiments, perceived motion direction was biased toward the attended axis: horizontal motion predominated under horizontal attention, whereas vertical motion predominated under vertical attention. These results demonstrate that the spatial distribution of attention plays a functional role in motion correspondence and highlight attention as a key factor shaping apparent motion perception.