PSYCH 120A Chapter Notes - Chapter 4.1: Agnosia, Tachistoscope
Document Summary
Apperceptive agnosia: see object"s shape and color and position but can"t put elements together to perceive an intact object. Can"t copy drawings but can draw from memory. Associative agnosia: can see but can"t link what they see to their basic visual knowledge. Can recognize objects even when info is partial. E. g. can recognize chair even when someone is sitting on it. Variations in stimulus input complexity in object recognition. Bottom up processes: processes directly shaped by stimulus (data driven) Top down processes: processes shaped by knowledge; concept driven. Objects are recognized by virtue of their parts. Recognition begins with identification of visual features in the input pattern. Specialized cells in the visual system act as feature detectors when relevant input is in view. People are efficient when searching for a target defined by a simple feature. Much slower when searching for a target defined as a combination of features.
