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Contrast is a feature of visual stimuli that characterizes the difference in brightness between dark and light regions of an image. Perception of contrast is affected by the temporal frequency and spatial frequency properties of a stimulus, and the sensitivity to contrast in sine wave stimuli is characterized by the contrast sensitivity function.
The Chubb illusion is similar to another visual illusion, the contrast effect.The contrast effect is an illusion in which the perceived brightness or luminance of an identical central visual target form on a larger uniform background varies to the test subject depending on the ratio of the central form's luminance to that of its background. [4]
A contrast effect is the enhancement or diminishment, relative to normal, of perception, cognition or related performance as a result of successive (immediately previous) or simultaneous exposure to a stimulus of lesser or greater value in the same dimension. (Here, normal perception, cognition or performance is that which would be obtained in ...
While being one of the most well-known contrast illusions, there are similar effects which cause two regions of identical color to appear differently depending on context: The Cornsweet illusion creates a boundary between two identically-shaded regions with a discontinuous gradient, resulting in the opposing sides appearing to be different.
In contrast, associative agnosia is a type of agnosia where perception occurs but recognition still does not occur. [1] When referring to apperceptive agnosia, visual and object agnosia are most commonly discussed; this occurs because apperceptive agnosia is most likely to present visual impairments. [ 2 ]
The Posner cueing task, also known as the Posner paradigm, is a neuropsychological test often used to assess attention. Formulated by Michael Posner, [1] it assesses a person's ability to perform an attentional shift. It has been used and modified to assess disorders, focal brain injury, and the effects of both on spatial attention.
Contrast effects are common in many perceptual modalities, and are similar to physiological adaptation. Adaptation can be explained as a change in the gain of the system, the gain being set to the appropriate level for maximum discrimination and for protection against sensory overload.
On the right side, the same dark areas are interpreted as belonging to the dark mist. In the meanwhile, the white parts are seen as the color of the discs. Therefore, our perception of the lightness of the discs is significantly influenced by the display, which is the mist in this case (Anderson & Winawer, 2005).