Is prior knowledge of object geometry used in visually guided reaching?

Area of Science:

• Cognitive Psychology
• Neuroscience
• Visual Perception

Background:

• The hollow-face illusion demonstrates how prior knowledge of face geometry influences perception.
• This illusion occurs when a concave mask is perceived as a convex face, overriding visual cues like binocular disparity.

Purpose of the Study:

• To investigate if prior knowledge of face geometry affects visually guided reaching.
• To determine how the visual system integrates prior assumptions with binocular disparity information.

Main Methods:

• Participants performed visually guided reaching tasks towards computer-generated normal and hollow faces.
• Depth information from binocular disparity was manipulated to either align with or contradict prior knowledge of face geometry.
• Verbal estimates of distances were also collected for comparison with reaching data.

Main Results:

• Reaching movements were significantly influenced by prior knowledge of face geometry, favoring a convex perception.
• Hollow faces were verbally estimated as being flatter than normal faces.
• The magnitude of the hollow-face illusion showed similar effects in both reaching and verbal estimation tasks.

Conclusions:

• The visual system integrates prior assumptions about face geometry with incoming visual data (binocular disparity) rather than solely relying on one.
• Prior knowledge of face geometry plays a crucial role in visually guided actions, such as reaching.
• The hollow-face illusion's impact is consistent across different perceptual and motor tasks.