The psychological refractory period as a function of performance of a first response

Proponents of a “single channel” theory of the psychological refractory period have not specified whether the single channel occupies only the decision component of the response selection, only the motor or response component, or both. In this experiment, the delay in the RT to the second of two successively presented stimuli was examined as a function of whether or not an overt motor response was made to the first stimulus, keeping the decision component constant. It was found that in both conditions RT₂ was delayed, suggesting that the decision component was a part of the single channel. However, RT₂ was delayed by a significantly greater amount if a motor response was required, indicating that the motor component is part of the single channel as well. Implications of the results for an expectancy theory of the psychological refractory period are discussed.     

Contralateral and heteromodal interaction effects in somatosensation: Do they exist?

In this paper we concern ourselves with the problem of whether or not conditioning stimuli of other modalities or stimuli applied to a distant locus of the body interact with a sensitive test of somesthetic temporal acuity we have called the gap test. The results of the experiment indicate that visual stimuli do not exert an observable influence on this temporal judgment, but that auditory stimuli and contralateral stimulation in the same modality do show a significant but relatively small effect. This is compared and contrasted with the very large and persistent effect reported when the conditioning stimulus is applied to the same electrodes as the gap test. By comparing our results with experiments of similar design carried out on lower animals by other investigators, some insights into the neural localization of the reported effects is obtained.     

Rehearsal grouping and hierarchical organization of serial position cues in short-term memory

Lists of 8, 9, or 10 digits were presented at the rate of 1 digit/sec. to subjects instructed to rehearse silently the digits in non-overlapping groups of 1, 2, 3, 4, or 5 digits, after hearing each digit. Subjects were instructed not to rehearse any digits outside the group currently being presented. Rehearsing in 3's was optimal, irrespective of list length. Both recall of items and recall of the correct positions of items improved from 1's to 2's to 3's. Recall of items declined very little from 3's to 4's to 5's, but recall of position declined sharply. Errors in positioning digits tended, above chance, to be in the same group or the same position in a different group. The results suggest that both item-to-item associations and serial positin-to-item associations are formed in short-term memory, that only two or three serial position cues are used, but that these serial position cues can be hierarchically organized into a beginning, middle, and end group and a beginning, middle, and end position within a group.     

The effect of encoding training on perceptual recall

The effect of encoding training on tachistoscopic performance was measured by training groups of Ss in either an octal or a standardized English encoding of nine place binary numbers. A control group of Ss was allowed to encode ad lib during an equivalent training period. Performance was measured before, during and after the encoding training. It was found that imposing a code on S impaired tachistoscopic performance both during and for some time after the encoding training. Possible reasons for this effect are discussed.     

The pastor and his privacy

Pastoral Psychology -