Relational dynamics inform predictive motor planning and perception

Area of Science:

• Neuroscience
• Human-Computer Interaction
• Physics

Background:

• Static object features like size and material influence lifting forces and perceived weight.
• Object motion and collisions provide dynamic cues about physical properties, but their impact on motor planning and perception is less understood.

Purpose of the Study:

• To investigate if dynamic cues from object collisions influence anticipatory lifting forces and perceived weight.
• To explore the sensorimotor system's integration of momentum conservation into motor planning and perceptual judgments.

Main Methods:

• Developed a hybrid virtual-reality/real-object paradigm.
• Participants viewed VR movies of collisions with varying mass ratios and restitution coefficients.
• Measured forces used to pick up co-located real objects mirroring virtual motion.

Main Results:

• Lift forces were significantly influenced by object motion after impact.
• A novel dynamic weight illusion was observed, where motion cues altered perceived object weight.
• Demonstrated that dynamic relational cues, not just static features, bias anticipatory force and perception.

Conclusions:

• The sensorimotor system integrates conservation of momentum into motor planning and weight perception based on dynamic motion cues.
• Motion cues alone can shape both motor planning for lifting and the perception of an object's heaviness.
• Findings suggest a direct perceptual encoding of physical interactions, grounding intuitive physics in sensorimotor systems.