The influence of previous experience upon perceptual pattern recognition is widely recognized among researchers in cognitive psychology. For example, an accepted experimental technique is "priming"--that is, the deliberate modification of a subject's perceptual responses by previous exposures to related stimuli. For an introductory survey of pattern-recognition research, see Margaret W. Matlin, Cognition, 3d ed. (New York: Harcourt Brace, 1994), 27-43.