Adaptation effects in grasping the Müller-Lyer illusion

Area of Science:

• Cognitive Psychology
• Neuroscience
• Perception-Action

Background:

• Pictorial illusions can influence grasping actions.
• Adaptation to illusions during grasping is debated, with some studies showing decreasing effects and others showing constant effects.

Purpose of the Study:

• To investigate adaptation to the Müller-Lyer illusion during grasping using an error-correction model.
• To examine how intermixing different illusion types (incremental and decremental) affects adaptation.
• To determine the influence of object size variation on adaptation rates.

Main Methods:

• Applied an error-correction model to experimental data from 40 participants grasping the Müller-Lyer illusion.
• Participants grasped targets within incremental and decremental Müller-Lyer displays, presented in mixed or separate blocks.
• Systematically varied the number of object sizes per block.

Main Results:

• Found significant interference between incremental and decremental illusion types when presented in the same block, impacting adaptation rates.
• Adaptation rates were consistent with model predictions.
• Varying the number of object sizes per block did not affect the rate of adaptation, also consistent with the model.

Conclusions:

• Error-correction models can parsimoniously explain perception-action dissociations in grasping-of-illusion paradigms.
• Experimental design, specifically the intermixing of illusion types, influences observed adaptation rates.
• The findings support the view of pictorial illusions as perturbations of perceived size that can be learned through sensorimotor adaptation.