Ap psych. frq homework

Lecturer Number Perceptual or object constancy refers to the tendency for viewed objects to appear very similar in terms of shape, color, size or location in spite of having a wide range of differences in observational conditions such as distance, lighting, angle of perception. The impressions created to the perceiver, conform to the perceived object as it really is or as it is assumed to be as opposed to the actual stimulus. It is perceptual constancy that enables perceivers, whether human or animals, to identify different objects under different conditions. Snow, for instance will appear white in the moonlight. It will also appear the same in sunlight, almost a million times brighter. Perception constancy however differs according to environmental cues and experience where the lower the number of cues and experience, the lower the ease of identification.
There are a number of perceptual constancies.
Lightness constancy is the tendency for an object being perceived as having the same level of brightness under a wide range of illumination conditions.
Color constancy is the tendency for a given color to appear the same under a wide range of conditions of viewing.
Shape constancy refers to the tendency of perceiving the shape of a solid object as being constant the differences in the angle of viewing and subsequently shape of the image projected on the retina of perceiver notwithstanding.
Size constancy is the tendency of perceiving the size of an object familiar to the perceiver as being the same, the distance and hence difference of size of image projected on the retina notwithstanding.
Visual perception in humans and animals is complex process. The act of visually perceiving starts when the pupil, a hole in the eye’s iris opens and allows light into the back of the eye. The eye’s lens then focuses an image of an object in its surroundings onto the retina, a light-sensitive membrane located in the back of the eye. The retina in essence is a component of the brain isolated to act as a transducer, in the light pattern conversion into neuronal signals. The retina has photoreceptive cells which detect the light photons projected by the lens and responds by giving out neural impulses. The signals are then processed in the thalamus of the brain, a relay station that for neuro impulses. It is in the thalamus where feature detection takes place and the brain is able to identify visual stimulus features, such as edges, lines, angle or movement. In this way one is able to visually perceive (see ) an object.
Works cited
Jessell, Thomas , Kandel, et al.. ” 27. Central visual pathways”. Principles of neural science. 16 Apr. 2000. Web. 28 Aug 2009.