Hand movements respond to any motion near the endpoint

Area of Science:

• Neuroscience
• Motor Control
• Human Perception

Background:

• Hand movements are often influenced by motion signals near their intended endpoints.
• It remains unclear whether this response is automatic or depends on perceiving the moving object.

Purpose of the Study:

• To investigate whether perceived surface motion influences the pull of hand movements towards action endpoints.
• To differentiate between automatic responses to local motion and goal-directed adjustments.

Main Methods:

• Participants aimed to intercept a moving target presented on either an occluded (tile) or non-occluded (frame) surface.
• The surrounding square (tile or frame) briefly moved, creating local motion signals.
• The size of the square was manipulated to vary the eccentricity of the motion signal.

Main Results:

• Both tile and frame conditions produced similar hand movement responses.
• Increasing the size of the square (motion signal eccentricity) reduced the response magnitude for both conditions.
• The perceived motion of the underlying surface did not affect the observed hand movement bias.

Conclusions:

• The observed hand movement bias is driven by local motion signals near the action endpoint.
• The brain does not appear to consider the motion of the surface itself when generating these movements.
• This suggests an automatic response to motion cues rather than a complex analysis of the moving environment.