Detection of stimulus change: The hypothetical roles of visual transient responses

Two random-dot patterns (D1 and D2) were displayed briefly in close temporal succession, separated by an interstimulus interval (ISI). The two patterns were identical except that D2 could contain one more element (addition) or one less element (subtraction) than D1. Observers were required to detect the addition or subtraction using a two-alternative forced-choice method. Three experiments were designed to examine Phillips and Singer’s (1974) suggestion that detection of additions and subtractions can be explained in terms of neural ON and OFF responses. Experiment 1 replicated Phillips and Singer’s finding that performance is progressively impaired as the ISI is increased. In Experiment 2, sudden shifts in luminance between D1 and D2 were combined with several durations of ISI to produce transient responses in a novel manner. Experiment 3 explored the roles of transient neural responses and of configurational changes as determinants of performance. Most predictions based on Phillips and Singer’s model were confirmed by the experimental outcomes. Some discrepancies between theory and data are noted, and directions for further research are suggested.     

Transgression and altruism: A case for hedonism

A model to account for the positive relationship between transgression and altruism was proposed and tested against three alternative formulations—Guilt, Social Justice, and Self-esteem Bolstering. The proposed model, Negative State Relief, asserts that people in a transgression situation behave charitably in order to reduce a general, negative affective state which is induced by exposure to harm-doing and that if the negative state is relieved by some other means, benevolent activity will be rendered unnecessary. All of the experimental subjects were exposed to an act of transgression; half performed the act themselves while half only witnessed it. In one set of experimental conditions (the relief conditions), a positive event—the receipt of either money or approval—was interposed between the harmful act and a fellow-student's request for aid. In another set of experimental conditions (the norelief conditions), no such positive event occurred. It was found, as predicted, that subjects who received a positive event were significantly less helpful than those who did not, but were not different from a control group which had never been exposed to the transgression. It was also found that harm-doers and harm-witnesses were identical in benevolent tendency. The results were interpreted as favoring a hedonistic conception of the nature of altruism. Finally, it was contended that a U-shaped relationship exists between mood state and helping tendency.     

The black sheep effect: Judgmental extremity towards ingroup members in inter-and intra-group situations

Two experiments yielded further evidence for the black sheep effect (Marques, Yzerbyt and by ens, 1988). In the first experiment, 66 subjects were presented with two good or two poor speeches, one supposedly made by an ingroup member and the other supposedly made by an outgroup member. In the second experiment, 37 subjects were presented with one good and one poor speech supposedly made either by two ingroup members or by two outgroup members. The black sheep effect was predicted and found in both experiments: subjects over-evaluated likeable ingroup members and under-evaluated unlikeable ingroup members as compared to equally likeable and unlikeable outgroup members. Collapsing the data of the two experiments suggests that social comparison may be performed, in purely symbolic terms, against a cognitive standard of positivity rather than an outgroup present in the judgmental situation. The emergence of the predicted effect when strongly individualized information was presented in inter- as well as in intra-group situations supports the robustness of the black sheep effect.     

A systemic approach to the treatment of depression with only one family member present

The purpose of the present article was to demonstrate a systemic treatment of depression for a 70 year-old woman. In this treatment, other family members were unavailable, but a family therapy systems perspective was used throughout. Results of the demonstration ABAB single case design and two year followup were suggestive of treatment effectiveness in decreasing depression. The need for additional replication of the study was noted.     

Two-dimensional filtering,oriented line detectors,and figural aspects as determinants of visual illusions

Quantitative data of Müller-Lyer illusions from the literature were analyzed according to three different models. All three models predict the illusion effect, although with different magnitude and different parameter dependency. First, a filter model describing a certain amount of blurring of the retinal picture seems partly responsible for the observed illusion. With reasonable estimation of the filter constants, however, a sufficient magnitude of illusion cannot be obtained. A second model of oriented line or bar receptors is even less effective in explaining the observed length illusions. A third model, consisting of a size-constancy operator triggered by depth cues, may predict effects larger than actually observed. It is concluded that figural aspects such as depth-inducing cues are mainly responsible for the illusion effects observed in Müller-Lyer figures.     

Constraints on Pavlovian conditioning of the pigeon: Relative conditioned reinforcing effects of red-light and tone CSs paired with food

Recent Pavlovian conditioning experiments presented all possible CS-US combinations of red-light and tone CSs and food and shock USs to separate groups of pigeons. Pigeons receiving shock USs demonstrated conditioned head raising followed by prancing to both CSs, but CRs were acquired more rapidly to tone than to red light. Although pigeons receiving food USs rapidly acquired a conditioned response of pecking to the red-light CS, there was no evidence of conditioned responding in groups receiving tone-food pairings. This outcome left open the possibility that Pavlovian pairings of tone and food may have resulted in association formation that was not revealed in performance. The present series of experiments attempted to reveal that association, using an indirect method of assessment, conditioned reinforcement. Experiment 1 demonstrated that both red light and tone paired with food became positive conditioned reinforcers, suggesting that an association between tone and food was formed in the same number of Pavlovian conditioning trials that previously failed to yield any direct evidence of conditioning. Experiment 2, which presented fewer conditioning trials, revealed that the tone-food association was formed less rapidly than the red light-food association. Experiment 3 demonstrated that the observed outcomes were not attributable to unconditioned, rather than conditioned, reinforcing effects of the Css.     

Illusion in a three-dimensional Hering figure in relation to viewing distance

Two groups of 34 Ss each judged the amount of illusion in a three-dimensional Hering figure at three viewing distances (9, 18, and 36 ft). The horizontal bars could be located in the foremost frontal plane of the three-dimensional display or could be recessed within it. Group C-F began at the close distance and Group F-C at the furthest distance. Amount of illusion increased with viewing distance and was greater with the bars recessed within the display. At the furthest distance, but not at the other distances, amount of illusion was greater for Group F-C. The results confirm predictions from Gregory’s theory of primary constancy scaling but are also interpretable in terms of local effects at the intersections of parallel bars and background lines.