The >S"' s task was to list all the 4-letter words he could make up from a set of 5-10 different letters. Responses occurred rapidly at first and then more slowly as S exhausted his store of words. When S had more letters to work with, he could generate a greater total number of words, but took longer to produce any given fraction of them. Thus with 5 letters, 5 found 80% of his limit of 8 words in less than 5 min., whereas with 10 letters, S took more than 15 min. to find 80% of his limit of 43 words. The results were analyzed in terms of a model that compared the retrieval of information from memory to a search process.

This study concerns eye movements recorded during a vigilance situation. Evidence was obtained on where people looked when they were watching for signals, which were 0.5-sec. pauses in the motion of a slowly revolving pointer. The following results were obtained: (1) Detection probability for two dials was approximately half the detection rate for one dial. (2) Analysis of eye-movement records showed that in the one-dial situation every missed signal was fixated without being recognized. (3) In the two-dial condition, signals were not only either fixated or unfixated, but some were fixated for part of their duration. Approximately one-third of the signals fell into each fixation category. (4) In contrast to the one-dial condition, the largest proportion of unreported signals for two dials were not fixated at all. Nearly as many unreported signals were partially fixated. About one-quarter of the unreported signals were fixated for their full duration. (5) Individual Ss differed with respect to the time they paused on one dial before shifting to the other. Those who shifted more frequently detected more signals.

A luminous bar was presented to each eye so that the 2 bars appeared to cross in the center of the binocular field. Rivalry occurred at the intersection, where each bar seemed alternately before or behind the other. Raising the illumination of both bars increased their alternation rate to a level that held constant at higher brightnesses, until the rate declined when the light became very intense. With both bars illuminated equally, one S reported the right bar dominant more than half the time; another S reported the left bar dominant. Raising the illumination of 1 bar increased the duration that it prevailed. Prevalence increased steeply at low intensities, leveled off at higher intensities, and finally declined when the bar became glaringly bright. After viewing 2 bright bars, S reported rivalry between their afterimages, which demonstrates that rivalry can occur when the stimuli occupy fixed retinal locations.

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2 experiments examined the relationship between search time and number of targets searched for. The 1st experiment photographed S's eye movements as he compared 2 groups of letters to determine whether one was a subset of the other. The time spent searching the containing set increased in proportion to the number of target letters it contained. In this case, search time included the time spent recognizing all the targets. The 2nd experiment photographed S's hand movements as he canceled just-learned target letters in English text.Here search time was measured so that it excluded the accumulation of recognition times. Search time still increased with the number of targets being sought.