Dynamical evolution of motion perception.
Motion is defined as a sequence of positional changes over time. However, in perception, spatial position and motion dynamically interact with each other. This reciprocal interaction suggests that the perception of a moving object itself may dynamically evolve following the onset of motion. Here, we show evidence that the percept of a moving object systematically changes over time. In experiments, we introduced a transient gap in the motion sequence or a brief change in some feature (e.g., color or shape) of an otherwise smoothly moving target stimulus. Observers were highly sensitive to the gap or transient change if it occurred soon after motion onset (< or =200 ms), but significantly less so if it occurred later (> or = 300 ms). Our findings suggest that the moving stimulus is initially perceived as a time series of discrete potentially isolatable frames; later failures to perceive change suggests that over time, the stimulus begins to be perceived as a single, indivisible gestalt integrated over space as well as time, which could well be the signature of an emergent stable motion percept.
Kanai
Ryota
R
Universiteit Utrecht, Helmholtz Research Institute, Psychonomics Division, Heidelberglaan 2, NL 3584 CS Utrecht, The Netherlands. kanair@caltech.edu
Sheth
Bhavin R
BR
Shimojo
Shinsuke
S
D003118:Color Perception; D005133:Eye Movements; D005863:Gestalt Theory; D006801:Humans; D007600:Judgment; D008960:Models, Psychological; D009039:Motion Perception; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D013028:Space Perception; D013997:Time Factors