Perception

Human beings possess five basic perceptual systems. The basic orientation system informs us of the position of the body in relation to the environment through receptors sensitive to gravity, such as those in the vestibular mechanism in the inner ear. The haptic or tactual system responds to pressure and temperature sensations using the skin, muscles, and joints. The haptic system uses the kinesthetic sense (information from the muscles), and the proprioceptive sense (information from the skeletal joints). The auditory perceptual system allows us to locate the sources of sounds, and to recognize organized sound structures such as speech and melodies. What is often called the savory system combines the senses of taste and smell which are intimately related. They both respond primarily to chemical aspects of the environment. The visual system responds to light received through the eye, or more precisely, the light sensitive cells of the retina. Fully functioning visual systems perceive color, distance, depth, motion, and form.

While perception involves information coming in from all of the sense modalities, psychologists have tended to focus on visual perception. This is because many aspects of visual perception are not easily explained by sensory processes alone, they seem instead to involve more higher-level brain processing than, for instance, taste, or scent perception. For the same reasons, this entry emphasizes visual perception.