Perception refers to the detection and interpretation of sensory information. Sensory information consists of different forms of energies (light radiation, pressure waves, chemical features, mechanical stimulation) that are detected by the sensory organs (eyes, ears, nose, tongue, skin). Detected energies are converted into electrical signals that are conveyed to the brain resulting in various sensations (seeing, hearing, smelling, tasting, feeling). People interpret incoming information in terms of meaningful and coherent messages (e.g., speech). The interpretation involves the integration of sensory information both within senses (e.g., grouping of auditory frequencies) and across senses or modalities (e.g., combining and integrating the auditory speech signals and visual speech-articulation).

Sensory information is grouped in such a way that what is perceived is an organised whole (i.e., Gestalt) and the whole is said to be more than merely the sum of its elements. For example, visual or auditory elements that are similar or are near to each other are perceptually grouped according to the grouping principles similarity and proximity, respectively. Perceptual illusions are often used to illustrate perceptual grouping. Perception is also affected by learning and various cognitive-affective variables, such as attention, intention, motivation, emotion, and so on.

The involvement of cognitive processes in perception has been emphasized in information processing approaches (e.g., Marr, 1982). On the other hand, ecological theories of perception (e.g., Gibson, 1979) argue that perception is direct and involves no mediating cognitive processes.

Perceptual research involves a range of areas (e.g., perception of depth, size, colour, movement, action, music, speech, etc…). The experimental investigation of perception involves analysing the accuracy of identification responses (e.g., naming or labelling) and discriminative responses (e.g., same/different, higher/lower). Methods also include classical psychophysics (e.g., the method of constant stimulus differences, method of limits, method of adjustment) and signal detection theory. In addition, neuroimaging techniques (e.g., PET, fMRI) enable scientists to investigate patterns of neural activity that occur in the human brain in response to certain sensory stimulation.

Practical implications of perception research involve the understanding of perceptual losses due to aging, disease, or injury. Research contributes to designing devices to restore lost perceptual abilities (e.g., hearing aids), and devising treatments for perceptual problems, such as dyslexia (difficulty in reading). Investigating perception also allows researchers to implement training methods to improve the safety of activities that rely heavily on perception (e.g., driving cars, piloting airplanes, etc…).

Reference Book

Goldstein, E. B. (2002). Sensation and perception (6^th Ed.). Pacific Grove, CA: Wadsworth-Thomson Learning.

Recommended Reading

Bregman, A. (1990). Auditory scene analysis. Cambridge, Mass: MIT Press.

Gibson, J. J. (1979). The ecological approach to visual perception. Boston: Houghton Mifflin.

Gregory, R. L. (1997). Eye and brain: the psychology of seeing (5^th Ed.). Princeton University Press.

Green, D. M., & Swets, J. A. (1988). Signal detection theory and psychophysics. Peninsula Publishing.

Marr, D. (1982). Vision: a computational investigation into the human representation and processing of visual information. San Francisco: W.H. Freeman.

Summary Written By

Bettina Keresztesi

MARCS Auditory Laboratories

University of Western Sydney