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Oh-Sang Kwon, David Knill; Temporal dependency in estimation of target velocity disappears in self-generated stimuli. Journal of Vision 2012;12(9):426. doi: 10.1167/12.9.426.
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© ARVO (1962-2015); The Authors (2016-present)
Motivation: It has long been reported that perceptual estimation of stimulus is biased toward the immediately preceding stimulus (Holland & Lockhead, 1968), and we have recently shown that the bias is modulated by the temporal correlation of stimuli history (Kwon and Knill, VSS 2011). Here, we asked whether the temporal dependency in perceptual estimation can be modulated by the observers’ prior knowledge on how the stimuli velocities are generated. Method: We used a motion extrapolation task in which a target moved and disappeared behind an occluder and subjects had to hit the target when it was supposed to be in the designated hitting zone. In the first condition, subjects actively generated the velocity of target (active condition) by hitting the virtual target with a pusher. The target launched when the pusher contacted target at the speed of the pusher. The same group of subjects participated in the second condition. In the second condition, the stimuli velocity was passively presented, but the sequence of stimuli velocities was what the same subjects generated in the first condition (active-passive condition). In the third condition, a new group of subjects participated. The sequence of stimuli velocities was the same as the other conditions (passive condition). Results: The bias toward the immediately preceding velocity was close to zero in the active and the active-passive conditions, whereas the bias was significantly different from zero in the passive condition. On the contrary, the bias toward the mean velocity was comparable in all three conditions. Conclusions: Temporal dependency in estimation of velocity disappears when subjects actively generated stimuli. Surprisingly, the same effect was observed when the stimuli were presented passively, if subjects know that the sequence of stimuli generated by themselves. Perceptual estimation of stimulus velocity is modulated by subjects’ prior knowledge on how the stimuli are generated.
Meeting abstract presented at VSS 2012
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