Within-category discrimination of musical chords: Perceptual magnet or anchor?

Recent speech research has begun to evaluate the internal structure of categories. In one such study, Kuhl (1991) found that discrimination was poorer for vowel stimuli that were more representative of the category (prototype, or P, set) than it was for less representative stimuli (nonprototype, or NP, set). This finding was interpreted as indicating that a category prototype may function as a “perceptual magnet,” effectively decreasing perceptual distance, and thus discriminability, between stimuli. The present study examines the function of prototypes in a musical category—another natural, but nonspeech category. Paralleling the Kuhl study, representative (P) and less representative (NP) sets of major triad stimuli were constructed, based on equal temperament. Musically experienced subjects rated the stimuli in each set for goodness as a major triad, with the highest rated stimulus serving as a prototype standard for a subsequent discrimination task. Results from the discrimination task demonstrated better performance in the P context than in the NP context. The current nonspeech results indicate that a prototype functions as an anchor rather than a magnet. In addition to providing a natural, nonspeech standard for comparison with speech findings, the results provide some important insights into the nature of musical categories.     

Time,change, and motion: The effects of stimulus movement on temporal perception

The effects of stimulus motion on time perception were examined in five experiments. Subjects judged the durations (6–18 sec) of a series of computer-generated visual displays comprised of varying numbers of simple geometrical forms. In Experiment 1, subjects reproduced the duration of displays consisting of stationary or moving (at 20 cm/sec) stimulus figures. In Experiment 2, subjects reproduced the durations of stimuli that were either stationary, moving slowly (at 10 cm/sec), or moving fast (at 30 cm/sec). In Experiment 3, subjects used the production method to generate specified durations for stationary, slow, and fast displays. In Experiments 4 and 5, subjects reproduced the duration of stimuli that moved at speeds ranging from 0 to 45 cm/sec. Each experiment showed that stimulus motion lengthened perceived time. In general, faster speeds lengthened perceived time to a greater degree than slower speeds. Varying the number of stimuli appearing in the displays had only limited effects on time judgments. Other findings indicated that shorter intervals tended to be overestimated and longer intervals underestimated (Vierordt’s law), an effect which applied to both stationary and moving stimuli. The results support a change model of perceived time, which maintains that intervals associated with more changes are perceived to be longer than intervals with fewer changes.     

“Subordination” and sensitivity to nonverbal cues: A study of married working women

Sex Roles - Women's superiority in decoding nonverbal cues of emotion has often been discussed as an adaptation to low status. To examine the relation of status to nonverbal sensitivity,...     

Shape discriminations of three-dimensional objects depend on the number and location of bends

In three experiments, subjects made shape discriminations of three-dimensional objects differing in orientation, number of bends, and location of bends (e.g., the central arm vs. a minor subarm). In general, encoding times at 0° disparity on bothsame anddifferent trials were affected by the number of bends, but only after a certain threshold of bends in the objects had been reached (Experiment 1). This effect was not due to the subjects’ having to search for matching ends of the objects (Experiment 2). In contrast, rotation rates were influenced by the location of the bends, but not by the number of bends per se (Experiment 3). The results support a representational scheme that is hierarchical, but not necessarily one in which the principal axis of an object is paramount.     

A reason for theoretical terms

The presence of nonobservational vocabulary is shown to be necessary for wide application of a conservative principle of theory revision.Support for this research was provided by the Office of Naval Research under contract No. N00014-87-K-0401. We thank Daniel Andler and Clark Glymour for helpful discussion.     

Attentional Focus of Students with Hyperactivity During a Word-Search Task

Mirrors have been used to focus attention to aspects of the self (e.g., to known strategies, standards). We hypothesized that this could be important for students with hyperactivity/inattention, who typically direct attention outward to external novelty. In this study, we administered a partially solvable word puzzle to 43 middle school students, with and without hyperactivity/inattention, in the presence and absence of a mirror, counterbalanced for condition and form order. Differences between students with hyperactivity/inattention and comparisons in accuracy were found only in the no mirror condition. Furthermore, the beneficial effect of the mirror for children with hyperactivity/inattention was most pronounced for those who looked at the mirror. Findings were interpreted in terms of their potential to remedy the production deficits of these children.     

Using a Conceptually-Based Predictor of Tenure to Select Employees

This paper describes the development and validation of a personnel selection instrument designed to predict employee tenure. The instrument was developed using models of employee turnover, psychodynamic theory, and beliefs regarding the optimal way to advance one's career. Four predictive designs were conducted to validate the instrument. Correlation coefficients ranged from .14 (p < .07) to .28 (p < .05) in predicting tenure.     

Dispositionai Optimism as a Protective Factor in Resisting HIV Exposure in Sexually Active Inner-City Minority Adolescents1

Recent investigations have explored dispositional optimism as a determinant of various health-related behaviors, though such research has been infrequently conducted in populations where pessimism would be expected to be prevalent. The present study examines optimism and unsafe sexual behavior in 230 sexually active inner-city minority adolescents. Findings suggest that dispositional optimism is a protective factor regarding adolescents' intentions to avoid engaging in unsafe sex. Further, the benefits of optimism appear to be explained by those who are more optimistic having higher levels of perceived condom use self-efficacy and stronger negative expectancies toward unsafe sex. Future interventions may need to address optimism in concert with behavioral-specific determinants to increase the probability of reducing unsafe sexual behavior in high-risk populations.