Expectations about motion direction affect perception and anticipatory smooth pursuit differently.

Area of Science:

• Neuroscience
• Cognitive Science
• Vision Science

Background:

• Smooth pursuit eye movements and motion perception integrate sensory input with past experience.
• Expectations shape anticipatory pursuit and can influence motion perception, though studies often examine them separately.

Purpose of the Study:

• To directly compare the effects of direction expectation on perception and anticipatory pursuit within a single task.
• To investigate whether expectation influences visual perception and eye movement responses similarly or differently.

Main Methods:

• Participants (n=10) viewed random-dot kinematograms with varying probabilities of rightward/leftward motion to establish directional expectations.
• Perceptual judgments of low-coherence stimuli were compared with anticipatory pursuit eye movements recorded under different probability conditions.

Main Results:

• Anticipatory pursuit velocity scaled with probability and showed an attraction bias, aligning with directional expectations.
• Perceptual judgments exhibited a repulsion bias, being influenced opposite to the expected motion direction.
• Control experiments ruled out retinal slip and motion adaptation as causes for the perceptual bias.

Conclusions:

• Direction expectation is processed differently for perception and anticipatory pursuit.
• Opposite biases suggest distinct ways perception and action utilize prior information.
• Findings support the concept of separate information processing streams for perception and pursuit.