Perception
Perception (from the Latin perceptio, percipio) is the organization, identification and interpretation of sensory information in order to represent and understand the environment. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs. For example, vision involves light striking the retinas of the eyes, smell is mediated by odor molecules and hearing involves pressure waves. Perception is not the passive receipt of these signals, but can be shaped by learning, memory and expectation. Perception involves these "top-down" effects as well as the "bottom-up" process of processing sensory input. The "bottom-up" processing is basically low-level information that's used to build up higher-level information (i.e. - shapes for object recognition). The "top-down" processing refers to a person's concept and expectations (knowledge) that influence perception. Perception depends on complex functions of the nervous system, but subjectively seems mostly effortless because this processing happens outside conscious awareness.
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Famous quotes containing the word perception:
“The perception of the comic is a tie of sympathy with other men, a pledge of sanity, and a protection from those perverse tendencies and gloomy insanities in which fine intellects sometimes lose themselves. A rogue alive to the ludicrous is still convertible. If that sense is lost, his fellow-men can do little for him.”
—Ralph Waldo Emerson (1803–1882)
“In England we have come to rely upon a comfortable time-lag of fifty years or a century intervening between the perception that something ought to be done and a serious attempt to do it.”
—H.G. (Herbert George)
“In the new science of the twenty-first century, not physical force but spiritual force will lead the way. Mental and spiritual gifts will be more in demand than gifts of a physical nature. Extrasensory perception will take precedence over sensory perception. And in this sphere woman will again predominate.”
—Elizabeth Gould Davis (b. 1910)