How different sources of visual perceptual information shape intentions, perceptions, and actions during one-handed catching

Van der Kamp and colleagues (2008) contended that interceptive actions involve the integration between separate, yet complimentary, cortical pathways responsible for visual perception. The ventral stream is proposed to be responsible for object identification and determining an intended response, while the dorsal stream is considered to be responsible for ongoing regulation of action. These ideas imply that manipulation of different information sources during performance of an interceptive action might lead to the emergence of distinct movement pattern profiles. In this experiment we examined these ideas by studying hand kinematics and eye movements of participants as they attempted to catch balls projected from a novel apparatus that coupled video of a throwing action and a ball projection machine. Participants coordinated their actions in three conditions: no video – ball projection only; matching condition – ball projection synchronised with video of an actor throwing a ball; mismatch condition – ball projection speed not synchronised with video of the throwing action. Results revealed that patterns of hand movements and gaze behaviours were influenced by absence of perceptual information of the throwing action; movement initiation occurred later, the hand moved faster, and reached its maximum grip aperture faster in the no video condition (ball flight only). Fewer image areas were sampled, tracking began later, and less of the ball’s trajectory was tracked in the no video condition as well. There were no performance differences between the matching and mismatch image synchronisation conditions. Data were congruent with contentions of Van der Kamp and colleagues (2008), demonstrating that advanced perceptual (ventral) information is important for shaping intentions, perception and action regulation, while ball flight (dorsal) information is mainly used to guide action during task performance