Individual response patterns in binary choice tasks with nondiscriminable stimuli

The present experiment sought to determine whether individual Ss tend to employ repeatedly the same response patterns in binary choice tasks containing nondiscriminable stimuli and, if so, whether the response sequences when used to constructstimulus sequences improve the performance of other choice tasks. Information and frequency analyses of the response sequences of 48 Ss showed moderate consistency of patterning within a light and within a tone task. Performance of a card task following the light and tone tasks was closely related to the task (light or tone) from which the stimulus sequence was obtained. The frequency analysis showed that repetition patterns were preferred by most Ss but at the expense of alternation responses. The presentation of reinforcement in the card task did not improve performance over that observed in the light and tone tasks.     

Negative recency and event-dependence

In a two-choice situation with event-probabilities of 0.67 and 0.33, recency effects were studied as a function of (a) event-dependence and (b) fore-knowledge of event-probabilities. The following conclusions are drawn: (1) Belief in some kind of event-dependence is a necessary condition for the occurrence of negative recency; (2) Foreknowledge of the event-probabilities does not affect recency phenomena; (3) The behaviour of subjects in the two-choice situation, is less irrational than some writers have claimed.     

Emotional trauma in rats: Age as a factor in recovery

Old (7 months of age) and young (2 months) male rats were divided into groups matched for spontaneous exploratory activity and for age. Experimental rats in the two age categories were then traumatized by giving them a 90 volt shock to the feet for two sec. on only one occasion. It was shown that nearly all the young rats recovered from the trauma within 5 weeks, as measured by brief exploratory activity and defecation, while at the end of 6 months the old rats still had not recovered. These results point up the greater resiliency of young animals, and the need for caution in the interpreting of research and theories on early experience.     

CULTURAL AND PHYSIOLOGICAL INFLUENCES UPON SPATIAL-PERCEPTUAL PROCESSES IN WEST AFRICA1 – PART I

Influences culturelles et physiologiques sur les processus spatio-perceptifs dans L'Ouest africain. 1^re partie. — Plusieurs études ont été réalisées dans le Sierra Leone pour tester la validité de certaines hypothèses relatives aux effets d'une culture tribale et d'un trouble endocrinien (Kwashiorkor) sur le développement de la dépendance vis-à-vis du champ et L'acquisition d'aptitudes spatio-perceptives. La première partie traite de la construction d'un test de tridimensionnalité, des variables culturelles et d'une expérience d'enseignement de la tridimensionnalité. La seconde partie présentera L'étude des variables endocriniennes et L'analyse factorielle pour L'ensemble des résultats.