Related Experiment Video
Updated: Jun 19, 2026

Perceptual and Category Processing of the Uncanny Valley Hypothesis' Dimension of Human Likeness: Some Methodological Issues
Published on: June 3, 2013
Sensitivity to attachment, alignment, and contrast polarity variation in local perceptual grouping
Louis K H Chan1, William G Hayward
1Department of Psychology, University of Hong Kong, Pokfulam, Hong Kong. clouis@graduate.hku.hk
Abstract:
A number of leading theories (e.g., Grossberg & Mingolla, 1985; Kellman & Shipley, 1991; Rensink & Enns, 1995) commonly assume that perceptual grouping by contour alignment occurs preattentively across reversing contrast polarity elements. We examined this notion in seven visual search experiments. We found that only grouping by attachment supported preattentive visual search and that grouping by contour alignment required attention in order to operate. Both attachment grouping and grouping by contour alignment were sensitive to contrast reversals. Further results showed that contour alignment was a strong grouping cue only among elements with the same contrast sign but that it did not facilitate grouping across reversing contrast. These results suggest that grouping by contour alignment operates only on inputs of consistent contrast polarity.
Related Concept Videos
Gestalt Principles of Perception
Group Polarization
Causes of Similarity-Dissimilarity Effect
Local Attraction
Perceptual Constancy
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...
Factors Influencing Attraction III: Similarity

