A reexamination of duplex perception evoked by intensity differences

Duplex perception is a term used to describe the simultaneous evocation of phonetic and nonphonetic percepts, a phenomenon held by some to reveal the operation of a specialized module for phonetic perception. In a widely cited experiment by Whalen and Liberman (1987), duplex percepts were created by replacing the third formant transition in a synthetic syllable with a sinusoidal tone glide and manipulating the level of the glide relative to the rest of the syllable. We discuss this study, and report four experiments. The first two made a systematic estimate of the “duplexity threshold”—the tone glide level at which a chirp-like sound could be heard as well as the speech-like syllable. In the third and fourth experiments, we used the results of the first to repeat and extend the experimental procedures in the original Whalen and Liberman study. We discuss the differences in outcome, and conclude that our results may be explained without the need to invoke a specialized phonetic module.     

Approximating a symmetric matrix

We examine the least squares approximationC to a symmetric matrixB, when all diagonal elements get weightw relative to all nondiagonal elements. WhenB has positivityp andC is constrained to be positive semi-definite, our main result states that, whenw1/2, then the rank ofC is never greater thanp, and whenw1/2 then the rank ofC is at leastp. For the problem of approximating a givenn×n matrix with a zero diagonal by a squared-distance matrix, it is shown that the sstress criterion leads to a similar weighted least squares solution withw=(n+2)/4; the main result remains true. Other related problems and algorithmic consequences are briefly discussed.     

EFFECTS OF RATER TRAINING AND PARTICIPATION ON COGNITIVE COMPLEXITY: AN EXPLORATION OF SCHNEIER'S COGNITIVE REINTERPRETATION

Schneier (1977) proposed that rater cognitive complexity interacts with format to affect the psychometric soundness of ratings. He also speculated that cognitive complexity may be enhanced by having raters participate in training and/or scale construction programs. This study was designed to test these latter hypotheses, while also providing a partial replication of Schneier's original research. Ninety-six undergraduate students were assigned to four groups. One participated in the construction of a set of BARS and was trained in their use, a second participated in BARS construction only, a third received training only, and the fourth served as a control group. All subjects were administered a measure of cognitive complexity before and after the experimental treatments. Also, all subjects evaluated five simulated ratees using the BARS. A training × participation (2 × 2) ANOCOV indicated no change in cognitive complexity scores as a result of the experimental treatments. A training × participation × (nominalized) cognitive complexity (2 × 2 × 2) MANOVA on mean ratings for the five stimuli found no effects on leniency error. A similar MANOVA on variances of ratings provided little evidence for effects on halo error. These results, taken in conjunction with those of other investigators who have failed to replicate Schneier's findings, suggest that the cognitive reinterpretation should be accepted with caution at best.     

BEHAVIORAL COMMUNITY PSYCHOLOGY: ENCOURAGING LOW-INCOME PARENTS TO SEEK DENTAL CARE FOR THEIR CHILDREN1

The present study examined the effectiveness and cost efficiency of three different techniques to encourage low-income rural parents to seek dental care for their children. The families of 51 children who needed immediate dental care (determined by dental screening at a local school) were placed into three matched groups and randomly assigned to the treatment conditions: One Prompt (Note Only), Three Prompt (Note, Telephone Contact, Home Visit), and One Prompt plus $5 Incentive. The Three Prompt and One Prompt plus $5 Incentive were significantly more effective in initiating dental visits than the Note-Only procedure. Not only was the One Prompt plus $5 Incentive technique effective in producing a slightly larger percentage of initial dental visits compared to the Three-Prompt technique, it also produced a significantly larger number of followup visits. Furthermore, the cost-effectiveness analysis showed the Incentive condition to be less costly than the Three-Prompt condition in encouraging initial dental visits.     

A PERFORMANCE-BASED LOTTERY TO IMPROVE RESIDENTIAL CARE AND TRAINING BY INSTITUTIONAL STAFF

Two experiments were conducted on four units of a residential facility for the multiply-handicapped retarded in an attempt to improve daily care and training services. Experiment I compared the effects of two procedures in maintaining the work performance of attendants, using an A-B design on two units. One procedure consisted of implementing specific staff-resident assignments, the other consisted of allowing attendants who had met performance criteria to be eligible for a weekly lottery in which they could win the opportunity to rearrange their days off for the following week. Results showed that the lottery was a more effective procedure as measured by the per cent of time attendants engaged in predefined target behaviors, and by their frequency of task completion in several areas of resident care. Experiment II replicated and extended these results to the area of work quality on two additional units, using a multiple-baseline design. The performance lottery was found to be an effective economical procedure that could be implemented by supervisory staff on a large scale.     

Teaching pedestrian safety skills to young children: an analysis and one-year followup

Twenty-four elementary school children in grades K-3 participated in a study to teach six street-crossing skills: (1) wait at curb, (2) look all ways, (3) watch vehicle distance, (4) walk, (5) continue to look, and (6) use crosswalk. The effects of an instructional package implemented on the street corner were evaluated using a multiple-baseline design across two groups of six children at each of two schools. Rapid acquisition of pedestrian skills was evident at both schools. Average skill levels improved from 44% during baseline to 97% after training at School A and from 21% to 86% at School B. Data taken at a second street at each school were used to assess setting generality of safety behaviors. A one-year followup of 14 children indicated that pedestrian safety skills either maintained at high levels or could be quickly recovered from intermediate levels after remedial training. This research represents a first step in the solution of just one of the many community problems involving safety-deficient settings.     

Choice for others and the perception of control

There has been an increasing emphasis in psychology on the perception of control over one's environment and its effect on behavior and performance. In the present experiment, subjects were allowed to choose material they would like to learn if given the opportunity, or allowed to choose material for others to learn. Their learning of a nonchosen (forced) set of materials was then examined and compared with that of subjects given no opportunity to choose at all. It was found that the choice-for-self condition led to better performance than either the choice-for-other condition or the nochoice (forced) condition. However, when an additional group of subjects was given the opportunity to choose for others and their personal involvement was augmented by emphasizing their willingness to choose, their performance was enhanced relative to subjects offered no choice. The results were discussed in terms of motivational benefits stemming from perceived control.This report is based on a thesis submitted by the first author to the Graduate School at Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the M.S. degree. The research was supported in part by a grant from the U.S. Army Research Office to the second author and by the Behavioral Research Directorate of the U.S. Army Human Engineering Laboratory. It may be reproduced in full or in part for any purpose of the United States Government.     

TEACHING MENSTRUAL CARE TO MENTALLY RETARDED WOMEN: ACQUISITION,GENERALIZATION, AND MAINTENANCE

We evaluated a training package designed to teach menstrual care skills to five mild to severely mentally retarded women. Three specific skill areas (changing stained underwear; sanitary napkin; and both stained underwear and sanitary napkin) were task analyzed and taught in a sequential manner. Results of a multiple-baseline design across women indicated that the training package was successful in teaching these skills; the women continued to perform the skills during naturally occurring menses up to 5 months following termination of the study.     

Utilization analysis of a pedestrian safety training program

A previously developed and analyzed pedestrian safety training program was used to teach appropriate street-crossing behaviors to kindergarteners and first graders. Adult crossing guards were trained to provide pedestrian safety instruction. Trained observers monitored the quality of instructions given by crossing guards and the pedestrian behavior of young children as they crossed the street. A multiple-baseline analysis of the effects of two training programs indicated that guards were able to deliver the pedestrian safety program to several groups of children with a high degree of competence after receiving a single videotape and role playing training session. Furthermore, children's level of appropriate street crossing increased contemporaneous to the change in guard behavior both on the street where training was delivered and on a second street where no training was previously delivered. Utilization analysis of the guard training program indicated that one cannot expect to produce consistently high levels of street-crossing behavior by implementing only the "show and tell" portions of the training package. Similarly, results suggested that one is unlikely to produce consistently high quality guard training behavior by only giving written instructions describing how pedestrian training should be administered.