Contrast effect
From Wikipedia, the free encyclopedia
A contrast effect is the enhancement or diminishment, relative to normal, of perception, cognition and related performance as a result of immediately previous or simultaneous exposure to a stimulus of lesser or greater value in the same dimension. (Here, normal perception or performance is that which would be obtained in the absence of the comparison stimulus - i.e., one based on all previous experience.)
Contrast effects are ubiquitous throughout human and non-human animal perception, cognition, and resultant performance. A hefted weight is perceived as heavier than normal when "contrasted" with a lighter weight. It is perceived as lighter than normal when contrasted with a heavier weight. An animal works harder than normal for a given amount of reward when that amount is contrasted with a lesser amount and works less energetically for that given amount when it is contrasted with a greater amount. A person appears more appealing than normal when contrasted with a person of less appeal and less appealing than normal when contrasted with one of greater appeal.
Simultaneous contrast refers to the manner in which the colors of two different objects affect each other. The effect is more noticeable when shared between objects of complementary color.[citation needed]
In the image here, the two inner squares are exactly the same shade, but they appear to have different shades due to the background provided by the outer squares.
This is a different concept than contrast, which by itself refers to one object's difference in color and brightness compared to its surroundings or background.
Successive contrast occurs when the perception of currently viewed test field is modulated by previously viewed test field.
For example, stare at the two coloured circles on the top row for a few seconds and then shift your attention to the two circles in the bottom row. These two circles, though identically coloured, would appear to be of different colours for a moment.
