BOUNDARY EXTENSION FOR BRIEFLY GLIMPSED PHOTOGRAPHS - DO COMMON PERCEPTUAL PROCESSES RESULT IN UNEXPECTED MEMORY DISTORTIONS

''Boundary extension'' is a memory illusion in which observers remembe r seeing more of a scene than was shown. Two experiments tested the po ssibility that this spatial distortion occurs soon after picture perce ption. In Experiment 1, undergraduates viewed close-up or wide-angle p hotographs for 250 ms or 4 s. Recall and recognition tests followed. B rief presentations yielded as much boundary extension as long presenta tions. In Experiment 2, picture triads were presented at a rate of 333 ms per picture with no interstimulus interval. After 1 s, one picture repeated and remained in view while subjects indicated whether it was the same or showed more or less of the scene. Even when conditions mi micked a series of rapid eye fixations, boundary extension occurred. T he presentation of a picture appears to activate a perceptual schema t hat allows observers to understand it in a larger context and this pro cess distorts memory for its actual boundaries. (C) 1996 Academic Pres s, Inc.