Inter-hemispheric differences in problem solving

Previous studies of a difficult reasoning problem have elicited inconsistent utterances. This study tested the hypothesis that the inconsistency is due to an asymmetrical encoding of the problem between the two hemispheres in the brain. The hypothesis was confirmed.

Retrieval of information from multiple ensembles in short-term memory

A recognition memory experiment investigated Ss' ability to organize information in short-term memory. A paradigm similar to that used by Sternberg was employed. A sequentially presented series of six digits (positive set) was shown with each digit appearing on a red, green, or amber background. The colors defined different ensembles, and responding to a test digit was contingent upon an item's membership in the positive set and the color-defined ensemble. Reaction time (RT) to the test digits indicated that Ss did organize information into ensembles. Furthermore, when informative cues were presented prior to the test item, Ss directed and confined their search to the cued subset.

Implicit alternatives to a stimulus, difficulty of encoding, and schema-plus-correction representation

Garner has hypothesized that a S exposed to a stimulus infers alternatives to it. Data are reviewed which establish a close correlation between the number of implicit alternatives to a stimulus and the difficulty of encoding that stimulus. This correlation provides a datum to be explained and suggests that the identification of specific implicit alternatives may provide clues to the encoding process. For dot patterns of a certain kind, it has been suggested that the rotations and reflections of a stimulus are its only alternatives, but a close examination of certain data indicates that, for many of these patterns, the alternatives also include one or more other patterns which differ from the stimulus only in the position of a single dot and which locate that dot in a position where it is more predictable from the other dots. It is suggested that the one-dot-different alternatives represent schemas used in schema-plus-correction encoding.

Tachistoscopic recognition of syllabicated words

In Experiment I, two-syllable words were presented in a multi-channel tachisto-scope. The whole word (W), first syllable (S1), and second syllable (S2) were displayed independently according to various schedules of successive 50-ms exposures; the exposures were in immediate succession, with no break apparent to the subject. Accuracy of identifying the words was facilitated by presenting a syllable before or after the whole word (S1W, S2W or WS1, WS2) in comparison with presenting the whole word alone (W). Presentation of the whole word for 100 ms (WW) produced better performance than sequential presentation of the first syllable, the whole word, and the second syllable for 50 ms each (S1WS2); the whole-word presentation (WW) was also superior to the reverse sequence (S2WS1). In Experiment II, strings of random digits were presented in the formats of S1WS2, WW, and S2WS1. Unlike the results of Experiment I, performance in the sequential conditions was not different from that in the simultaneous condition. It was concluded that sequential tachistoscopic presentation does not affect identification of unrelated characters, although it does disrupt the process of word recognition. Three hypotheses to explain the disruption were discussed: distortion of phonological representation, interruption of medial letter clusters, and fragmentation of the whole word.

Pictorial coding of verbal descriptions

Two experiments are described in which subjects matched written verbal descriptions against pictures of geometric shapes. The first experiment demonstrated that a difference in reaction time between simultaneously displayed description picture and picture-picture combinations was entirely eliminated when a I-S delay occurred between the stimuli, implying that the description might be converted to a pictorial form of coding. A second experiment assessed the effects of variation in the complexity of the verbal description on description-picture comparison times, where the two displays might be presented simultaneously, or successively, with the description first, or the picture first. Complexity interacted with presentation conditions, having its greatest effect on the Simultaneous condition and least effect on the Successive condition in which the description preceded the picture. Some theoretical implications of these results are discussed.