Perceptual scaling of synthesized musical timbres: Common dimensions,specificities, and latent subject classes

To study the perceptual structure of musical timbre and the effects of musical training, timbral dissimilarities of synthesized instrument sounds were rated by professional musicians, amateur musicians, and nonmusicians. The data were analyzed with an extended version of the multidimensional scaling algorithm CLASCAL (Winsberg & De Soete, 1993), which estimates the number of latent classes of subjects, the coordinates of each timbre on common Euclidean dimensions, a specificity value of unique attributes for each timbre, and a separate weight for each latent class on each of the common dimensions and the set of specificities. Five latent classes were found for a three-dimensional spatial model with specificities. Common dimensions were quantified psychophysically in terms of log-rise time, spectral centroid, and degree of spectral variation. The results further suggest that musical timbres possess specific attributes not accounted for by these shared perceptual dimensions. Weight patterns indicate that perceptual salience of dimensions and specificities varied across classes. A comparison of class structure with biographical factors associated with degree of musical training and activity was not clearly related to the class structure, though musicians gave more precise and coherent judgments than did nonmusicians or amateurs. The model with latent classes and specificities gave a better fit to the data and made the acoustic correlates of the common dimensions more interpretable.     

Analysis of long-term stress reactions in emergency room patients: An initial study

The psychological stress reactions of 44 family medicine patients who were treated in the emergency room were examined approximately a year after the event. Patients were assessed on several psychological measures, including one for posttraumatic stress disorder (PTSD), and on their perception of how stressful the event was initially and now. Results show continuing stress reactions related to the emergency room event. Three patients endorsed symptoms indicating full PTSD and 13 appeared to have at least partial PTSD. Age appeared to be a factor in the presence of stress symptoms and in degree of perceived communication with the physician.     

Evaluation of a Coeducational Interactive Rape Prevention Program

This article illustrates one way in which counselors can contribute to victim services on campus besides providing direct remedial services. Specifically, the authors describe a project in which they designed, implemented, and evaluated a rape prevention program. The program was coeducational and interactive and was presented to members of sororities and fraternities. Those who participated in the program endorsed fewer rape-supportive attitudes than did the control group immediately following the program, although the two groups no longer differed at the one month follow-up. Recommendations are provided for counselors interested in developing and evaluating similar programs.     

Illusions of Safety in a Risky World: A Study of College Students' Condom Use

The role that costs, benefits, and perceptions of invulnerability play in condom use was examined in a sample of students ( N = 211) at 4-year and 2-year colleges. In multiple regression analyses, past condom use was related to relative invulnerability, low present risk, and inexperience. Less intended condom use was associated with high perceptions of relative invulnerability and low perceptions of present risk. It appears that many college students feel protected from HIV because they judge their current sexual environment to be safe due to monogamy, sexual history taking, and the ability to tell a partner's HIV status. Independent of that, feelings of relative invulnerability are associated with more condom use—perhaps an accurate judgment of past risky behavior.     

Children's knowledge of the separation of variables concept

Children 8, 10, and 13 years of age were either given prior experience constructing seriations or matrices with two-dimensional stimuli, or no prior experience. Knowledge of the separation of variables concept was then assessed by examining children's use of controlled tests of a problem variable's effect (probe questions), and recognition of the inadequacy of confounded variable tests (negative counter-suggestion questions). Although many children either passed both questions or failed both questions, a significant number of children correctly used controlled variable tests, and yet failed to recognize the inadequacy of a confounded test. These results suggest that although a preliminary form of the separation of variables concept is characterized by use of controlled variable tests, subsequent refinement of the concept includes recognition of the inadequacy of confounded tests. Relative to seriation, prior experience constructing matrices facilitated recognition of a confounded test's inadequacy. Constructing matrices may have focused attention on the simultaneous variation of problem elements on multiple dimensions and thus facilitated recognition of the necessary role of both variation of stimuli on test dimensions and equality of stimuli on nontest dimensions, e.g., a controlled test.     

The availability explanation of excessive plausibility assessments

The assessment of hypotheses in hypothesis generation involves a comparison between those hypotheses that have been generated (specified) and those that are not generated (unspecified). Experiment 1 was an investigation of an “availability explanation” for subjects' overconfidence in the probability of specified hypotheses. The conjecture is that subjects have difficulty retrieving unspecified hypotheses from memory. Therefore, the underpopulated set of unspecified hypotheses is assessed as less probable then it actually is and the specified set is assessed as more probable. Two manipulations to increase the availability of unspecified hypotheses were investigated. One involved explicitly requesting subjects to populate the unspecified set; the other was a computer presentation of candidate unspecified hypotheses. Results of experiment 1 were that assessment overconfidence for both experimental groups was reduced. The results support the conjecture that the availability heuristic is at least partially responsible for subjects' overconfidence. The main result of experiment 2 was that the overconfidence bias persisted with different assessment methods for both subject-generated and experimenter-supplied hypotheses.     

Classes,collections, and distinctive features: Alternative strategies for solving inclusion problems

This study analyzed the strategies that children ages 5 through 8 years used on two modified versions of Inhelder and Piaget's (The early growth of logic in the child. New York: Norton, 1964) class inclusion task. In two experiments, children were tested on Wilkinson's (Cognitive Psychology, 1976, 8, 64–85) “percept” inclusion task in which distinctive features marked both supraordinate and subclasses. It was hypothesized that children who fail standard Piagetian inclusion tasks succeed on the “percept” task by counting and comparing mutually exclusive features rather than using features as markers for classes and subclasses. The hypothesis was supported by children's performances on “percept” tasks in which solutions based on feature counting conflicted with solutions based on consideration of class inclusion relations. In two other experiments, children answered part-whole and part-part comparison questions in which both terms were described as classes and/or subclasses, or in which one of the two terms was described as a collection (e.g., a bunch of grapes). These experiments contrasted Markman and Seibert's (Cognitive Psychology, 1976, 8, 561–577) “organization” hypothesis that the greater psychological integrity of collections facilitates reasoning on part-whole comparison problems with the hypothesis that the faciltative effect results from the “large number” connotation of collective nouns. Results on collection problems in which parts were described as collections supported the “large number” hypothesis. Results were discussed in terms of their implications for Piaget's theory.     

The role of structural components in the Mueller-Lyer illusion

In order to assess the role of the structural components of the Mueller-Lyer illusion, subjects reproduced the central extent of standard Mueller-Lyer figures and configural variations. Illusory magnitude of the underestimated wings-in and overestimated wings-out figures was examined with selective amputations of the oblique wings and central line segment (shaft). Variations were presented at 0, 45, 90, and 135 deg from vertical. Orientation had no reliable effect on illusory magnitude. Elimination of the shaft effected a decrease in the apparent extent for all variations, presumably due to the addition of the filled-unfilled space illusory effect to the standard Mueller-Lyer effect. A second study corroborated this finding The decrease in apparent extent consequent to shaft removal occurred independently of any response factor. Selective wing removal differentially decreased the illusory magnitude of the standard Mueller-Lyer figures; this was discussed with regard to a dual-illusion hypothesis. Finally, variations that contained no intersecting lines produced a significant illusion in the direction of the standard Mueller-Lyer figures, suggesting the involvement of higher level, nonperipheral distortion mechanisms.     

A dual look at spontaneous cooperative play in the preschool: Free play versus structured environment

An observational study was conducted during free play among preschool children (N = 36) to identify the component skills of spontaneous cooperative play. Early techniques of spontaneous cooperation were found to be action-oriented and/or self-referenced statements contributing to thematic dialogue. Advanced techniques informed partners of abstract use of props and advised them on how to interact. A reliability study introduced dyads of older preschoolers (N = 60) to structured sets of play materials. In addition to supporting the display of components revealed in Study I, results indicated that 5-year-olds were better able than 4-year-olds to respond to the demand characteristics of the structured setting. Comparisons by sex, partnerships, and types of play materials were also analyzed.