Vibrotactile masking: A comparison of psychophysical procedures

The amounts of ipsilateral and contralateral masking obtained with a modified psychophysical procedure were compared for vibratory stimuli presented to different body loci. Results of a combined forced-choice localization task and a forced-choice detection task were similar to the results obtained in previous investigations which employed method of limits and two-alternative, temporal forced-choice procedures, respectively. Ipsilateral maskers produced similar amounts of masking in both the detection and localization tasks for fingertip and arm test sites. Contralateral maskers resulted in considerably more masking in the localization task than in the detection task for both fingertip and arm test sites. When large longitudinal distances were introduced between the test stimulus and masker, little masking was evident in either the localization or detection task. It was concluded that the differences in the amount of ipsilateral and contralateral masking obtained with different psychophysical procedures reflect different effects of a masker on the detectable attributes of a test stimulus. Implications of these results for the study of multiple tactile perception were discussed.     

Summation of pain produced in different anatomical regions*

Unescapable shock was administered to rats in a spatial preference task through pairs of electrodes implanted subcutaneously near the neck and tail. The animals were permitted to choose between shock through both pairs of electrodes or through one pair by crossing from one side of a cage to the other. Rats preferred shock in two locations to an equal amount in one location. The results indicate that summation of pain is greater when stimuli are added in the same rather than in different places.     

Effects of a prosocial televised example on children's helping

The possibility that regularly broadcast entertainment television programs can facilitate prosocial behavior in children was investigated. Thirty first-grade children, 15 boys and 15 girls, were individually exposed to one of three half-hour television programs: a program from the Lassie series which included a dramatic example of a boy helping a dog, a program from the Lassie series devoid of such an example, or a program from the family situation comedy series, the Brady Bunch. The effects of the programming were assessed by presenting each child with a situation that required him to choose between continuing to play a game for self-gain and helping puppies in distress. Children exposed to the Lassie program with the helping scene helped for significantly more time than those exposed to either of the other programs.     

Harmonic structure as a determinant of melodic organization

Musicians and nonmusicians indicated whether a two-note probe following a tonally structured melody occurred in the melody. The critical probes were taken from one of three locations in the melody: the two notes (1) ending the first phrase, (2) straddling the phrase boundary, and (3) beginning the second phrase. As predicted, the probe that straddled the phrase boundary was more difficult to recognize than either of the within-phrase probes. These findings suggest that knowledge of harmonic structure influences perceptual organization of melodies in ways analogous to the influence of clause relations on the perceptual organization of sentences. They also provide evidence that training plays an important role in refining listeners’ sensitivity to harmonic variables.     

An investigation of repetition and language processing in a case of conduction aphasia

A study is reported of a single case of conduction aphasia. A battery of tasks designed to investigate the parameters of the patient's severe repetition deficit is supplemented by tests of several language functions. The results provide extensive information on a wide range of the patient's language abilities and are used to evaluate the adequacy of four models that have been offered to account for conduction aphasia. An argument is made in support of the suggestion that the syndrome of conduction aphasia should be divided into two subgroups based on patients' ability to select and realize phonemes in speech output. It is concluded that the best explanation for the disorder of patients with repetition deficit but without significant speech output problems is the hypothesis that repetition ability is compromised by a pathological limitation of auditory-verbal short-term memory. This hypothesis is extended to account for the pattern of results obtained in the language tasks.     

The effect of varying stimulus context on word-finding ability: Dyslexia further differentiated from other learning disabilities

All learning-disabled children, dyslexic and nondyslexic, were found to be impaired relative to controls on a variety of naming tests: (1) naming pictured objects (visual name), (2) responding with an object name to a definition (auditory definition), (3) completing a sentence with an object name (auditory sentence), or (4) naming palpated objects (tactual). Only on the sentence completion task (auditory sentence), which has been found to be the simplest response mode, were the dyslexic subjects selectively less accurate than the nondyslexic learning disabled, relative to the control group. Although dyslexic subjects tend to circumlocute when naming objects, they did not find it easier, relative to other groups, to give the function rather than the name of objects. Time scores were not in the same direction. The nondyslexic learning-disabled group responded more rapidly than either the dyselxic subjects or controls and made more perceptual errors, findings that may be related to some other factor, possibly the hyperactivity of many of the children in the nondyslexic learning-disabled group. The finding, also, that most of their naming error scores correlate highly with each other as well as with standardized language measures (WISC-R Vocabulary and PPVT), whereas those of the dyslexic and control groups do not, further suggests some underlying pathology to which their language disability is related. Language impairment, then, may be a common factor in all learning disability, dyslexic and nondyslexic, possibly for different reasons.     

Seeing the baby: The impact of ultrasound technology

This paper reports results of a study of prenatal diagnosis patients who underwent ultrasound examinations and lost their pregnancies through miscarriage or elective terminations. The majority of the women felt that viewing the ultrasound image influenced their relationship to the fetus and their coping with the pregnancy loss. The women commented on the power of ultrasound to make their pregnancies more real as well as the painful yet sometimes beneficial consequences of seeing the fetus. Clinical implications are considered for health professionals who provide prenatal diagnostic services or counseling after pregnancy loss.     

Visual discovery in mind and on paper

The effectiveness of mental imagery with and without drawing support (perceptual assistance) in the visual synthesis of novel patterns was studied in three experiments. When the task was to create one recognizable pattern from three simple shapes in a 2-min assembly period, subjects were as likely to produce a recognizable or creative pattern per trial whether mental imagery was augmented by external drawing support or not. When the task was to create as many patterns as possible in a 3-min assembly period, more patterns were produced per trial with external drawing support than without; however, neither the recognizability nor the creativity of the patterns differed. Differences in performance in the visual synthesis task with and without external drawing support are interpreted in terms of limited cognitive resources.     

Computer Monitoring of Work Performance: Extending the Social Facilitation Framework to Electronic Presence1

This study demonstrated the utility of employing a social facilitation framework to the study of computer monitoring of work performance. The physical presence of an observer watching a subject work on a complex task (as a supervisor might “look over an employee's shoulder“) was contrasted with four conditions involving the electronic presence of computer-based work monitoring (as a supervisor might monitor an employee's work remotely via computer) and a control condition of subjects working alone without any monitoring of their work. Task performance was severely impaired for participants who were monitored electronically as well as for those who were monitored “in person.” Two interventions, providing participants with a sense of control over their work conditions and monitoring participants as a group rather than as individuals, each reduced the negative impact of monitoring on task performance by almost 40%. Results also indicated that individuals with an external locus of control (who believe reinforcements received are primarily determined by factors outside of themselves, e. g., other people) experience greater anxiety than those with an internal locus of control under monitoring conditions. Implications of these findings for social facilitation and the rapidly expanding use of computer-based work monitoring are discussed.     

USING TIME DELAY TO PROMOTE SPONTANEOUS SPEECH IN AN AUTISTIC CHILD

One of the frequently observed deficits in autistic children is their lack of spontaneous speech. We used a multiple baseline across behaviors to investigate the effectiveness of a time delay procedure for inducing spontaneous speech in a 10-year-old male autistic child during play. We first taught the child to imitate the experimenter's verbal prompts that described the child's motor response. Once the child reached criteria on imitation, we implemented baseline wherein an immediate verbal prompt for speech was provided after each of the child's motor responses. Intervention consisted of a gradual delay in the presentation of the verbal prompts. The time delay effectively increased the child's spontaneous speech on trained items; some generalization to untrained items also occurred, but only within the same behavioral class of car play. Generalization was also observed across settings. Spontaneous speech remained at high levels during the 4-month maintenance for the behavior of car play but decreased for a second behavior. Decreases in the child's response latencies suggest that spontaneous speech may be an anticipatory verbal response.