| Abstract: | Three experiments with 255 undergraduates and a 4th in which the author and 2 colleagues served as Ss showed that complex visual stimuli—pictures and digit arrays—were remembered better when shown at high luminance (LM) than at low LM. Evidence was found for the possibilities that lowering LM reduced the amount of available information in the stimulus and that lowering LM reduced the rate at which the information was extracted from the stimulus. When stimuli were presented at durations short enough to permit only a single eye fixation, LM affected only the rate at which information was extracted. Decreasing LM by a factor of 100 caused information to be extracted more slowly by a factor that ranged, over experiments, from 1.4 to 2.0. When pictures were presented at durations long enough to permit multiple fixations, however, LM affected the total amount of extractable information. In a 5th experiment, with 4 undergraduates, converging evidence was sought for the proposition that within the 1st eye fixation on a picture, LM affects the rate of information extraction. If this proposition is correct and the 1st eye fixation lasts until some criterion amount of information is extracted, then fixation duration should increase with decreasing LM. This prediction was confirmed. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
