A technique for the construction of discrete dichotic stimulation material

Procedures are described for the generation, synchronization. and accurate spacing of discrete dichotic stimulation material. A suggested standard definition of interpair interval is proposed.     

Control of-treadmill exercise of rats with hypothalamic stimulation

Running and resting behavior of rats was measured during treadmill exercise under conditions involving (1) rear-shock avoidance, (2) continuous electrical stimulation of the hypothalamus, or (3) no rear-shock and no hypothalamic stimulation. Hypothalamic stimulation was superior for eliciting consistent running with a minimum of resting. A second experiment demonstrated that decreases in hypothalamically elicited treadmill running resulting from prolonged exercise could be counteracted by increasing the intensity of the hypothalamic stimulus. A third experiment suggested that very little training was needed to induce a high and consistent level of running performance using hypothalamic stimulation.     

Detection and scaling of statistical differences between visual textures

Stochastically textured patterns were used to investigate the sensitivity of Ss to differences in the statistical distributions of locally defined properties of element density and shape. The results of the study indicate that when the textures were most structured, in terms of their variance, Ss were most accurate at detecting dissimilarities between pairs of patterns. Ss also rated the similarity of the statistical distributions of elements of patterns differing in local properties. Multidimensional scaling analysis of the ratings showed two dimensions, representing monotonic orderings of the stimuli.     

On the validity of scalp recordings of the auditory evoked potential

Simultaneous recording from scalp and cortical electrodes in unanesthetized and unrestrained cats revealed essentially no differences between the superficial and deep recordings of the auditory evoked responses. Human recordings taken under two conditions of muscular contraction contained no major differences from 30 to 300 msec after stimulus onset.     

Effects of deprivation and reinforcement-magnitude on response variability

Animals were trained to displace any one of five response keys in order to put themselves in a stimulus condition in which reinforcement could be obtained by depressing a response lever. Decreased deprivation and magnitude of reinforcement were found to increase the variability of the distribution of key responses. The relevance of these findings to other experiments in which deprivation, reinforcement magnitude, and intermittent reinforcement were studied is discussed.     

Several methods for teaching serial position sequences to monkeys

Three keys were available for monkeys to press. The objective was to teach the animals to press the keys in sequences up to 10 members in length. With fading procedures, a light that cued the correct key at a given serial member of the sequence faded out slightly each time the animal selected it, and became slightly brighter after the animal made an error at that sequence member. The correct keys were faded out, starting from the end of the sequence and proceeding toward the beginning. With control procedures, the cue lights were turned off suddenly, rather than being faded gradually. In almost every instance, the animals learned a longer series of unlighted key positions with the fading procedures than they did when each key-light was turned off suddenly. Also, requiring the animals to press a series of keys cued by lights before they could reach the sequence members they were to learn hampered them in learning the later serial members. By using several different sequences, it was possible to replicate these findings within the individual animal.     

SOME EFFECTS OF CULTURAL TRAINING ON LEADERSHIP IN HETEROCULTURAL TASK GROUPS1

Diriger des groupes de travail d'une autre culture : effets de I'initiation préalable à cette culture. — Etude exploratoire portant sur l'utilité de programmes d'enseignement culturel pour accroître l'efficacité de ceux qui sont amenés à diriger des groupes de travail appartenant à une autre culture que la leur. La recherche a porté sur vingt-quatre sujets américains (cadets ROTC, engagés volontaires dans une compagnie des Forces Spéciales de l'armée américaine) et a également requis la participation de douze étudiants arabes, inscrits à I'Université de l'Illinois. Les vingt-quatre sujets américains ont été divisés en deux groupes égaux d'après la note qu'ils ont obtenue au LPC (Least Preferred Coworker : partenaire le moins aimé) qui permet d'apprécier les attitudes manifestées dans l'exercice du commandement. Ces groupes sont de nouveau dichotomisés selon deux types de formation : douze sujets reçoivent pendant trois heures un enseignement programmé sur la culture arabe, les douze autres reçoivent un enseignement de même durée et de même forme, sur un sujet sans rapport avec la culture arabe, à savoir la géographie du Moyen-Orient. Après la phase d'enseignement, on demande à chaque S. américain de diriger un groupe composé de deux arabes et de lui-même. Chaque équipe de deux arabes est utilisée une fois dans chacune des quatre conditions expérimentales (deux types de chefs, deux types de formation), l'ordre étant contrebalancé. Chaque groupe travaille sur trois tâches différentes (une tâche coopérative non structurée, une tâche coopérative structurée, une tâche de négotiation). On obtient généralement un plus haut niveau de performance, mesurée à la fois par la productivité et par la qualité des relations dirigeant-dirigé, avec les moniteurs qui ont reçu un enseignement sur la culture arabe. On trouve également des différences entre les moniteurs libéraux, soucieux de bonnes relations inter-personnelles et les moniteurs autoritaires et répressifs. l'interaction entre I'initiation à la culture et le style de commandement montre que les moniteurs qui ont des styles différents bénéficient de manière spécifique du programme d'initiation culturelle. On constate que I'initiation à la culture et I'interaction face à face avec des gens d'une autre culture entraînent des changements positifs dans les attitudes.     

The true distributions of the range of rank totals in the two-way classification

This paper presents the results from an investigation of the true probability distributions of the range of rank totals. A procedure for generating an approximation to the true distributions is also given. A comparison of the results of this approximation with an extensive criterion of generated true and sample distributions, and with other approximations is indicated. Accurate estimates of the critical ranges necessary to reach significance at three commonly used alpha levels, where the number of judges and items is less than or equal to sixteen, are presented in tabular form.