The effect of gap depth on the perception of whether a gap is crossable

Four experiments were performed in order to examine the effect of gap depth on human observers’ perception of whether or not a gap is crossable. Experiments 1 and 2 showed that as the gap’s depth increased, observers tended to increasingly underestimate the maximum width of a gap they could step across. Experiments 3 and 4 clarified this finding: The observed covariation of perceived gap crossability and gap depth depended on the observer’s direction of gaze, rather than on the physical depth of the gap. The optical relations to which observers might be attending are discussed, as well as the possibility that cognitive-affective processes might have contributed to observers’ underestimation of their actual capabilities.     

Nonstranger sexual aggression: A discriminant analysis of the psychological characteristics of undetected offenders

Sex Roles - Rape is an underreported and underconvicted crime. Therefore, many highly sexually aggressive men are missed by research employing judicial identification for sample selection. The...     

Laterally induced impedance effects in vision

A linear integral equation for a system of mutually impeding points is developed and solved explicitly. Particular solutions are shown to be subharmonic functions for a large class of stimuli. Specialized forms of the general equation presented in this paper occur within a number of mathematical models of Mach bands. In addition to these known spatial properties, our results also show that the time course of this basic equation may be useful in developing models of transient neural activity as well as of temporal psychophysical phenomena, such as the Broca-Sulzer effect. Further, a spatial transfer function much like the low-frequency cutoff of empirically derived modulation transfer functions follows directly from our basic integral equation if the additional assumption of spatial homogeneity is imposed.     

Decreased helpfulness with increased group size through lessening the effects of the needy individual's dependency1

The present experiment attempted to integrate the research on helpfulness in which subjects work for someone else in an artificial laboratory setting (Berkowitz & Daniels, 1963; Berkowitz, 1972) with the bystander-intervention-in-emergencies studies often carried out under more realistic conditions (e.g., Latané & Darley, 1970; Schwartz & Clausen, 1970; Clark & Word, 1972). Fifty-six university women in a 2 × 2 factorial design were led to think they were working for a same-sex peer who could win a cash prize, although there was “nothing in it for them.” Half were told that the other's chance of getting the prize was greatly dependent upon their effort while the remaining participants were informed that the other did not need their-work very much. Moreover, half of the subjects thought they were the only ones working for the other whereas the remaining people believed there were two other co-workers and that the output from all three would be averaged. It was expected that the participants would feel the greatest personal responsibility to help the other and would work hardest for her when she was greatly dependent upon their productivity and they were the only worker, while the subjects would feel the lowest level of personal responsibility for their peer and would be least helpful to her when she was not particularly dependent upon them and there were two other co-workers. The findings are generally in accord with these expectations.     

The relationship between frontalis muscle activity and self-reports of headache pain

The relationship between levels of frontalis muscle activity and self-reports of pain was evaluated in two studies. In Study I frontalis muscle activity and self-reports of pain collected during biofeedback treatment of muscular contraction headache clients were correlated. In Study II frontalis EMG activity was increased and decreased using biofeedback techniques while concurrent reports of headache pain were recorded. The results of Study I indicated a significant relationship between EMG activity and reported headache pain for only two of the five subjects studied. The biofeedback procedures in Study II were associated with reliable increases and decreases in EMG activity. Concordance between EMG and pain reports occurred only during the EMG increase condition. Overall correlations were significant for one of the 2 subjects. The results suggest that EMG activity may not be sufficient to account for pain reports in all chronic headache clients, and variables other than EMG activity may be influencing reports of pain in some patients.     

Factors affecting judgements of how much another likes us: A signal detection approach

Investigated the effects of subjects' self-concept and the attractiveness of the other on subjects' estimates of how much the other liked them. The use of a signal detection paradigm allowed the measurement of both the criteria and discriminability of subjects' decisions. Eighty mule and 80 female subjects participated in a computer match where they received either somewhat positive or somewhat negative feedback from their match. Besides sex and type of feedback, the factorial design included dating self-concept (high vs. low) and other-attractiveness (high vs. low). Results indicate that high dating self-concept subjects had a lower criterion than low dating self-concept subjects for saying that another liked them (p < .0l), and that the former group was superior to the latter at discriminating between the two types of feedback (p < .03). Also, males were more willing to say that the attractive match liked them than that the unattractive match liked them, while among females the direction of these differences reversed (p < .03). fie results were explained in terms of differential attention to pay-off matrices and prior odds.     

A test of the hypothesis that Cronbach's alpha reliability coefficient is the same for two tests administered to the same sample

In measurement studies the researcher may wish to test the hypothesis that Cronbach's alpha reliability coefficient is the same for two measurement procedures. A statistical test exists for independent samples of subjects. In this paper three procedures are developed for the situation in which the coefficients are determined from the same sample. All three procedures are computationally simple and give tight control of Type I error when the sample size is 50 or greater.The author is indebted to Jerry S. Gilmer for development of the computer programs used in this study.     

Saccade latency and warning signals: Effects of auditory and visual stimulus onset and offset

Previous studies have found that a nonspecific visual event occurring at the fovea 50–150 msec after the onset of a peripheral target delayed the initiation of the saccade to that target. The present studies replicated and extended this finding by studying the effects of both visual and auditory warning signals, by examining the effects of onset and offset warning on manual response latency, and by investigating the effects of presenting the warning events in the periphery of the visual field. The results indicated that the interfering effects occur with visual but not auditory stimuli, with saccades but not motor responses, and when the visual warning event occurs either foveally or in the subject’s periphery. Implications for the processes involved are discussed.