Linking actions and objects: Context-specific learning of novel weight priors.

Area of Science:

• Cognitive Neuroscience
• Perception and Motor Control

Background:

• Weight prediction relies on learned associations (priors) linking object properties like size and material to weight.
• A key question is whether these priors are global or context-specific and how they are updated.
• The role of focused attention in updating priors and scaling lifting forces is also under investigation.

Purpose of the Study:

• To investigate whether weight prediction priors are context-specific or global.
• To determine if updating priors or scaling lifting forces requires focused attention.
• To compare the adaptability of weight predictions in lifting versus perceptual judgment tasks.

Main Methods:

• Participants interacted with size-weight inverted objects either passively or actively, under full or divided attention.
• The size-weight illusion was measured after repeated exposure to assess changes in weight perception.
• Lifting forces were monitored to evaluate the scaling of motor output.

Main Results:

• Attenuation of the size-weight illusion during lifting was context-specific, being greater when the interaction mode matched the assessment method.
• Dividing attention did not affect the updating of weight predictions for perceptual judgments.
• Dividing attention slowed the scaling of lifting forces when interacting with unusually weighted objects.

Conclusions:

• The brain appears to store multiple, context-specific representations of weight priors.
• Focused attention is essential for refining lifting forces but not for updating weight predictions used in perceptual judgments.