Perception (from Latin perceptio 'gathering, receiving') is the
organization, identification, and interpretation of sensory information in
order to represent and understand the presented information or environment.
All perception involves signals that go through the nervous system, which in
turn result from physical or chemical stimulation of the sensory system.
Vision involves light striking the retina of the eye; smell is mediated by
odor molecules; and hearing involves pressure waves.
Perception is not only the passive receipt of these signals, but it is also
shaped by the recipient's learning, memory, expectation, and attention.
Sensory input is a process that transforms this low-level information to
higher-level information (e.g.