Eye movements and pupil dilation during event perception

Human observers segment ongoing activities into events that are reliable across observers [Newtson and Engquist 1976]. Segments can be small ("fine") or large ("coarse") with clusters of fine-grained segments relating hierarchically to coarse segments. Segmentation behaviour occurs even without instruction indicated by neural activity in the Medial Temporal complex (MT+)and Frontal Eye Field (FEF). Similar activation is observed during active segmentation [Zacks et al. 2001]. These two brain regions are known to be active during the processing of visual motion (MT+) and guiding saccadic eye movements (FEF). This, along with behavioural evidence [Zacks 2004], indicates that visual motion may play an important role in identifying events