DEGREES AND DIMENSIONS OF SOCIAL INTERACTION IN TRIBAL GROUPINGS

On a administré un inventaire de quinze questions sociométriques à onze groupes d'élèves d'écoles primaires et secondaires, d'une école d'instituteurs, et d'une école pour jeunes mineurs de la region minière (Copperbelt) de Zambie (N = 274). Les choix ont été analysés en prenant l'origine tribale comme base de classification pour les groupements dans les classes et pour tous les répondants. l'origine tribale représente une catégorie importante pour l'interaction sociale à l'intérieur des groupes institutionnels quand la distance est grande. Les dimensions de l'inventaire, que fait apparaître une analyse factorielle basée sur les groupements par tribu des répondants, suivent trois axes et pourraient correspondre à l'autorité (leadership) dans un système institutionnel, l'acceptation par les pairs et l'origine ethnique. l'A. discute de ces résultats en se référant à d'autres recherches sur la distance sociale et montre quelles modifications de la théorie traditionnelle ils suggèrent.     

Successive luminance difference thresholds and brightness as a function of the interstimulus interval and durations of successive flashes

Monocular,successive luminance difference thresholds (ΔI) and brightness matches (PSE) were obtained by the method of constant stimuli for two flashes successively presented to the same retinal area. Variations in interstimulus interval first-flash duration,and second-flash duration were the independent variables investigated. ΔI decreased as a function of ISI,while PSE remained relatively uninfluenced. An intensity-duration reciprocity was observed with increases in either first- or second-flash duration. Equal increases in duration of both flashes led to a constant value of ΔI. A Broca-Sulzer effect was also noted. In another study, a 10-msec, variable-luminance Standard was followed after 500 msec by either a 10-msec or a 320-msec test flash that was compared to the Standard. The results indicated that the rate of change of brightness with changes in luminance of the Standard was faster for the 10-msec flash than for the 320-msec flash. The rate-of-change hypothesis would predict that the 10-msec flash should have the smaller ΔI. The results for two Ss indicated the opposite: AI was smaller for 320-msec than for 10-msec flashes. A modification of the hypothesis was suggested such that it may be the energy increment (Δlt) required for detection that is related to the rate at which brightness changes with energy.     

The effect of forced choice on color discrimination

Color discrimination ability was measured at four spectral regions usually named blue, green, yellow, and red. Two methods, temporal forced-choice and phenomenal report, were compared. Data suggest that for color discrimination, phenomenal report is a preferable technique.     

Theoretical models of choice and strategy behavior: Stable state behavior in the two-choice uncertain outcome situation

A theoretical approach to the understanding of human behavior in uncertain outcome situations is suggested, an approach which draws upon utility theory, decision-making theory, and statistical association theory. Experimental evidence supporting this approach as opposed to alternative approaches is summarized. Three different formalizations are presented, and a variety of experimental tests is suggested.This paper was written while the author was at the Center for Advanced Study in the Behavioral Sciences, and it has benefited greatly from discussions with many colleagues there. In particular, some of the features of Models I and II emerged from work with Robert P. Abelson, and Model III was developed to its present state partly as a result of consultations with Claude Shannon, and John C. Harsanyi (of the Department of Economics at Stanford University). The treatment of all three models was sharpened during many discussions with Robert M. Solow.