Binocular brightness combinations: Additive and nonadditive aspects

A conjoint measurement procedure is used for the measurement of binocular brightness as a function of left and right luminance inputs. For nonzero stimulation, the data confirm earlier findings: the system can be described as additive with a scale exponent of 1. If zero stimulation is included, however, no additive solution can be found (due to Fechner’s paradox). This fact, combined with various critical remarks in the literature with respect to the existence of a real luminance-averaging system, has led us to propose a model which takes account of Fechner’s paradox, and incorporates “realistic” exponents without requiring a multistage processing mechanism where different levels are characterized by different sensory scales. The proposed model makes the weighting coefficients for the two eyes dependent in a continuous way on the strength of stimulation in the two eyes, especially on the amount of contrast of the monocular stimuli. For zero background stimulation, contrast can be expressed in terms of luminance of the stimulus. In this way, the model is reduced to a simple testable form. While it much simpler than Engel’s (1969) model, the experimental results indicate that it might also work for the more general case.     

A COMPARISON OF NORTH-AMERICAN AND BRAZILIAN COLLEGE STUDENTs' PERSONALITY PROFILES ON THE 16 PF QUESTIONNAIRE

Le questionnaire de personnalité 16 PF (Forme A) a été traduit en portugais et soumis à un échantillon représentatif des étudiants de Sao Paulo (Brésil), comprenant 770 H et 555 F. Pour chaque facteur, les résultats ont été comparés à ceux d'un échantillon standardisé d'étudiants américains: les étudiants brésiliens sont, en général, moins sociables (A —) et moins enthousiastes (F —), plus soupçonneux (L +) et plus imaginatifs (M +); ils sont également moins conservateurs (Qi +) et plus indépendants (Q2 +). l'analyse de second ordre fait apparaître les Brésiliens comme plus anxieux et plus introvertis, montrant également plus de spontanéité et de créativité que les sujets américains. On constate enfin l'existence de différences entre hommes et femmes, tant à l'intérieur de chaque groupe qu'entre les deux échantillons.     

The influence of an interpolated experience upon recognition

It was demonstrated in a previous experiment that an experience interpolated between an original experience and its recall may bring about changes in the points of emphasis in the recall of the original experience. Moreover, details of the interpolated experience may be recalled as if they had formed part of the original experience. These results were taken to mean that two experiences of a related kind may become merged in memory into something akin to Bartlett's notion of an organized mass of past experiences. In the experiment here reported, the original experience was the hearing of a story, and the interpolated experience the seeing of a picture which illustrated part of the story. When in a recognition test subjects were asked to select from three alternatives (including the original) the one version which was “most like the original story,” a proportion of them preferred to the original story a version which differed from the original by including a number of details from the picture. Asked about details, all the subjects tended to place details from the picture in the story, even if they had not been mentioned there. The results of the two experiments are thought to show that irreversible changes are brought about in the memory of an experience by subsequent experiences of a related kind.     

Negative ions and behavior: impact on mood, memory, and aggression among type A and type B persons

Individuals scoring high (Type As), intermediate, or low (Type Bs) on the Jenkins Activity Survey were given an opportunity to aggress against a stranger who, previously, had either provoked or not provoked them. The opportunity to aggress (as well as all other aspects of the study) took place in the presence of (a) a high concentration, (b) a moderate concentration, or (c) a low (ambient) concentration of negative air ions. Results indicated that exposure to moderate or high levels of negative ions significantly enhanced aggression by Type A subjects, but not by other participants. In addition, we found that negative ions produced positive shifts in subjects' reported moods in the absence of provocation, but negative shifts in moods in the presence of provocation. These findings suggest that moderate or high concentrations of negative ions serve as a source of heightened activation, thus enhancing individuals' dominant reactions or tendencies in a given situation.