Limits on the applicability of signal detection theories

Two auditory signals were presented in random sequences in which the more intense signal came on.2, .5, or.8a/the trials. Each trial began with an intermediate tone which was identified in the instructions as either the standard for comparison or simply as a warning tone. Half the Os were instructed to discriminate whether the signal was “louder” or “softer” than the standard, the other half to recognize which signal had been presented. For both discrimination and recognition tasks, the total proportion of ldlouder” judgments was independent of the presentation probabilities, accuracy for each signal varying inversely with its probability of presentation. These results suggest strict limitations on the response optimization posited by theories of signal detection.     

Looking time: Experimenter and instruction effects

A 2 by 3 factorial design was used to investigate the effects of the instructions and the presence of E on looking time. Two hundred thirty-nine college students viewed 30 colored stimuli of landscapes, single objects, and arrays of objects under three different sets of instructions, with E either present or absent while S viewed the stimuli. The results demonstrated that E’s presence depressed the time spent looking at the stimuli Evidence was also found suggesting that ambiguity in the typical instructions given Ss in looking-time experiments may result in artifactually long looking times. It was concluded that a more appropriate situation to investigate looking time would (1) utilize sham GSR instructions to reduce S’s uncertainty concerning the experiment’s purpose, and (2) arrange for E’s absence while S is viewing the stimuli     

REPEATED MEMORY OF ORAL PROSE IN GHANA AND NEW YORK1

On a lu en anglais un court passage de prose à difféients groupes d'étudiants ghanéens et new yorkais. Ensuite, et par trois fois, on leur demande de dire ce qu'ils ont retenu. Le premier rappel a lieu après 30–45 minutes, le second et le troisiàme après plusieurs semaines. On a utilisé trois histoires différentes, mais chaque groupe de sujets n'en entendait qu'une seule. Les résultats montrent que, conformément à L'idée que la tradition orale est plus forte en Afrique Occidentale qu'à New York, les étudiants ghanéens retenaient mieux que les américains. Pour deux des histoires, on a enregistré peu de perte de rétention des thèmes entre le 1^er et le 3^e rappel; pour la troisiéme, entre le 2^e et le 3^e rappel. Mais la capacité à reteñir les thèmes de L'histoire ne s'explique pas uniquement par puré routine de mémoire. On peut penser que L'ordonnancement de L'histoire, loin de constituer un obstacle comme c'est souvent le cas quand on doit retenir dans L'ordre des faits sans liaison entre eux, favorisait ici la rétention des thèmes.     

College Major Choice and Personal Adjustment

This investigation focused on the differences in reported personal adjustment problems between freshmen students who made a congruent college major choice and students who made an incongruent choice. Personal adjustment was defined operationally with the Mooney Problem Checklist. Congruent and incongruent college major choice groups were defined operationally using the Vocational Preference Inventory. In the analysis of variance of the adjustment scores, the interaction term involving congruence of major choice and sex and the test for the main effect of sex were not significant. The test for the main effect of congruence was found to be significant. Subjects who had made a congruent college major choice reported fewer personal adjustment problems when compared to subjects in the incongruent group.     

Reaction time as a function of the intensity and probability of occurrence of vibrotactile signals

Three Ss made judgments of the presence or absence of a burst of 60-cps vibration onthe index fingertip.The probability of S’s reporting the presence of a signal was found to be influenced by signal probability and signal intensity. Mean reaction time for reporting the presence of a signal decreased as a function of signal intensity and signal probability whereas mean reaction time for reporting the absence of a signal increased as a function of signal intensity and signal probability. On trials where no signal was presented mean R T for reporting a signal decreased with increases in the signal probability whereas mean RT for reporting the absence of a signal increased with increases in signal probability. The results were interpreted as support for the hypothesis that S’s decision time was longer the closer on the sensory continuum a particular observation was to his criterion.