Related Experiment Video
Updated: Jun 19, 2026
06:53
Creating Virtual-hand and Virtual-face Illusions to Investigate Self-representation
Published on: March 1, 2017
Comment on 'angle illusion on a picture's surface' by Hammad et al. (2008)
1Psychology Department, American University, 4400 Massachusetts Avenue, Washington DC 20016, USA. lydia.maniatis@gmail.com
Spatial Vision
|November 7, 2009
Summary
The study questions Hammad et al.'s (2008) findings on angle illusions. Their data cannot definitively support their proposed explanation over alternative theories.
Area of Science:
- Visual perception
- Geometric illusions
- Cognitive psychology
Background:
- Hammad et al. (2008) proposed a theory for angle illusions based on surface properties of images.
- This study critically evaluates the empirical support for their conclusions.
Discussion:
- The data presented by Hammad et al. (2008) are insufficient to validate their specific hypothesis.
- Alternative explanations for angle illusions remain plausible given the existing evidence.
Key Insights:
- The conclusions drawn by Hammad et al. (2008) regarding the basis of angle illusions are not adequately supported by their experimental data.
- The study highlights the limitations in differentiating between theoretical models using the available evidence.
Outlook:
- Further research is needed to develop experiments that can distinguish between competing theories of visual illusions.
- Clarifying the mechanisms behind angle illusions requires more robust and discriminating data.
Related Concept Videos
01:13Contact Angle
When a solid is dipped inside a liquid, the liquid surface becomes curved near the contact. For some solid–liquid interfaces, the liquid is pulled up along the solid, while for others, the liquid surface is convex or depressed near the solid surface. This phenomenon can be explained using the concept of cohesive and adhesive forces.
The adhesive force is the molecular force between molecules of different materials, that is, between the molecules of the solid and the liquid. The cohesive force...
The adhesive force is the molecular force between molecules of different materials, that is, between the molecules of the solid and the liquid. The cohesive force...
01:21Gestalt Principles of Perception
Gestalt principles provide a framework for understanding how humans perceive objects as unified wholes within their context. These principles are essential in explaining the cognitive processes that make sense of complex visual stimuli by organizing them into coherent groups. One fundamental principle is proximity, which posits that objects located close to each other are perceived as a collective group. For instance, when dots are positioned near one another, the visual system interprets them...
01:15Depth Perception and Spatial Vision
Depth perception is the ability to perceive objects three-dimensionally. It relies on two types of cues: binocular and monocular. Binocular cues depend on the combination of images from both eyes and how the eyes work together. Since the eyes are in slightly different positions, each eye captures a slightly different image. This disparity between images, known as binocular disparity, helps the brain interpret depth. When the brain compares these images, it determines the distance to an object.
01:15Unsymmetric Bending - Angle of Neutral Axis
Unsymmetrical bending occurs when a structural member is subjected to bending moments in a plane that does not align with the member's principal axes. This scenario typically arises in beams and other structural components when loads are applied at non-ideal angles, introducing complexities in stress analysis.
When a bending moment is applied at an angle θ concerning the vertical axis of a symmetrical member, it can be resolved into components along the member's principal centroidal axes. The...
When a bending moment is applied at an angle θ concerning the vertical axis of a symmetrical member, it can be resolved into components along the member's principal centroidal axes. The...
01:30Oriented Surfaces
A surface is called orientable if a consistent choice of unit normal vector can be made at every point on the surface. A thin soap film stretched across a wire loop provides a familiar example. The film separates the air on one side from the air on the other, so one side can be selected as positive and the opposite side as negative. Once this choice is made, a unit normal vector can be assigned smoothly across the entire surface.At each point on the soap film, a unit normal vector points...