VISUAL PERCEPTUAL RATE UNDER 2 CONDITIONS OF SEARCH

Presented the digits in the number series 1-9 by means of a 10-channel tachistoscope in order at interstimulus intervals (ISIs) varying from 50-200 msec. between successive digits. 5 undergraduates were Ss. In the before condition, S was told prior to a trial for which digit he was to search. In the after condition, S was not told the target until termination of a trial. Thus, in the latter condition, S had to search for the gap in the number series. At 75 msec. ISI, performance was nearly perfect in the before condition, but in the after condition this level of performance was not achieved until ISIs of 200 msec. Results in the before condition were interpreted in terms of filter processes or multichannel feature analyzers that permit target search without encoding each of the noise elements. In the after condition detection of the missing number in the series required that each of the presented digits be processed through the encoding stage. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.