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We must begin by distinguishing between visual mental imagery and visual perception: Visual perception occurs while a stimulus is being viewed, and includes functions such as visual recognition and identification . Two types of mechanisms are used in visual perception: “bottom-up” mechanisms are driven by the input from the eyes; in contrast, “top-down” mechanisms make use of stored information . Visual mental imagery is a set of representations that gives rise to the experience of viewing a stimulus in the absence of appropriate sensory input. In this case, information in memory underlies the internal events that produce the experience. Unlike afterimages, mental images are relatively prolonged. (en) |
