The information available in brief visual presentations. Psychological Monographs: General and Applied, 74, 1-29
How much can be seen in a single brief exposure? This is an important problem because our normal mode of seeing greatly resembles a sequence of brief exposures. In this report, the following experiments were conducted to study quantitatively the information that becomes available to an observer following a brief exposure. Lettered stimuli were chosen because these contain a relatively large amount of information per item and because these are the kind of stimuli that have been used by most previous investigators. The first two experiments are essentially control experiments; they attempt to confirm that immediate-memory for letters is independent of the parameters of stimulation, that it is an individual characteristic. In the third experiment the number of letters available immediately after the extinction of the stimulus is determined by means of a sampling (partial report) procedure described. The fourth experiment explores decay of available information with time. The fifth experiment examines some exposure parameters. In the sixth experiment a technique which fails to demonstrate a large amount of available information is investigated. The seventh experiment deals with the role of the historically important variable: order of report. It was found that each observer was able to report only a limited number of symbols correctly. For exposure durations from 15 to 500 msec, the average was slightly over four letters; stimuli having four or fewer letters were reported correctly nearly 100% of the time. It is also concluded that the high accuracy of partial report observed in the experiments does not depend on the order of report or on the position of letters on the stimulus, but rather it is shown to depend on the ability of the observer to read a visual image that persists for a fraction of a second after the stimulus has been turned off.