HEURISTICS FOR DETERMINING THE OPTIMAL INTERVAL BETWEEN CHECKUPS

Abstract –How often should one check on a system that is at risk for some malfunction? The optimal interval between inspections depends on the likelihood of malfunction, the cost of inspection, and the cost of treatment We develop a mathematical expression for the optimal inspection interval as a function of these parameters and then an approximation for that expression The approximation indicates that as the risk increases or the ratio of inspection to disease cost decreases by a factor of n, the inspection interval should be reduced by n1/2 We also report an experiment indicating that subjects who generate optimal inspection intervals use examples as anchors and then perform adjustments for variations in risk and cost factors However, they do not approximate the appropriate square-root adjustment rule The observed anchor-and-adjust process suggests that normative recommendations may serve as influential benchmarks, even if they are not adhered to directly.     

Differential effects of frequency shifted feedback between child and adult stutterers

It has been reported previously that presentation of an altered form of the voice enhances the fluency of people who stutter. One of these forms of alteration is frequency shifted feedback. The effects of frequency shifted feedback was compared between two speaker groups that differed in age. The fluency enhancing effects of frequency shifted feedback was greater for adult speakers (mean age 21;3) than for children (mean age 9;11). The results are discussed in terms of their implications for theory and treatment.     

Tactile roughness perception with a rigid link interposed between skin and surface

Subjects made roughness judgments of textured surfaces made of raised elements, while holding stick-like probes or through a rigid sheath mounted on the fingertip. These rigid links, which impose vibratory coding of roughness, were compared with the finger (bare or covered with a compliant glove), using magnitude-estimation and roughness differentiation tasks. All end effectors led to an increasing function relating subjective roughness magnitude to surface interelement spacing, and all produced above-chance roughness discrimination. Although discrimination was best with the finger, rigid links produced greater perceived roughness for the smoothest stimuli. A peak in the magnitude-estimation functions for the small probe and a transition from calling more sparsely spaced surfaces rougher to calling them smoother were predictable from the size of the contact area. The results indicate the potential viability of vibratory coding of roughness through a rigid link and have implications for teleoperation and virtual-reality systems.     

Multipotential Abilities and Vocational Interests in Gifted Adolescents: Fact or Fiction?

The widely held view that highly intellectually gifted adolescents are multipotential in their abilities and career interests was investigated in two samples (N = 322 and N = 217) of gifted high school seniors. Three measures of intellectual abilities—verbal, mathematical, and mechanical—and a measure of vocational interest based upon nonacademic talented activities and accomplishments that yielded scores for vocational interest in three areas—Science, Social, and Artistic—were administered. Contrary to the widely held view, a very large proportion of intellectually gifted adolescents reported a differentiated pattern of both abilities and interests, and a very small proportion reported the expected high-flat ability and interest profiles. The findings suggest that the working assumptions of career education and counselling of intellectually gifted adolescents should perhaps be reconsidered.     

Integration of features in comparing multifeature stimuli

For a series of trials, the subject indicated whether or not two face-like stimuli were identical with respect to the features they contained (a positive or negative response, respectively); reaction time (RT) was recorded. The stimuli were separated by .5 or 4.0 sec, and each contained either two or three features. On some trials, the features of the first stimulus were represented within a single head outline; on others, they were distributed over several spatially separated outlines (components). Positive-response RT increased with the number of stimulus features and with the number of first-stimulus components (c); these two factors were additive. Negative-response RT increased with c, decreased with the number of differing features, and these two factors interacted. These effects did not vary with interstimulus interval. The results indicate that the subject did not integrate the first-stimulus components, but instead compared the second stimulus to each component, holistically (for positive responses) or analytically (for negative responses).     

Using visual codes for comparisons of pictures

In two experiments, Ss indicated for a series of trials whether or not two pictures of common objects had the same name (a positive or negative response, respectively). The pictures were separated by one of three interstimulus intervals (ISis), and reaction time (RT) was recorded. In Experiment I, positive trials involved pictures that were identical (identity match), mirror images (mirror match), or physically different but had the same name (name match). The stimuli came from either an S set, in which name-match pairs were physically similar, or a D set, in which name-match pairs were physically dissimilar. The mean RTs for mirror and identity matches were virtually the same but faster than name-match RTs, an advantage that decreased with increasing ISI. It was expected that name-match RT for the S set would be less than for the D set, indicating a facilitative effect of physical similarity; however, the identity-match RTs showed the expected difference. These results were extended in Experiment II, which involved only the identity and name matches, in pure sessions (which included positive trials of just one type) or mixed sessions (which included both types of positive trials). For mixed sessions, name- as well as identity-match RTs differed between the S and D sets. These results provide evidence for the use of visual codes in comparing nonidentical pictures, codes that apparently vary with experimental context and task demands.     

Bilateral tachistoscopic perception,handedness, and laterality: II. Nonverbal stimuli

Thirty-two Subjects were assigned to four groups on the basis of handedness (left or right) and familial sinistrality (absent or present). Their laterality patterns were investigated with a cued order-of-report paradigm. On each trial, Subjects saw a tachistoscopic presentation of two outline drawings of common objects, one drawing on the left of a central fixation point, one on the right. A centered arrowhead appeared with the pictures; the arrowhead pointed either left or right, and its direction indicated the order of report. The results for each group were discussed in terms of asymmetry for rate of processing and rate of decay, and in comparison with our earlier study of word recognition.     

Memory scans based on alternative test stimulus representations

In a search task similar to that used by Sternberg (1966), Ss were presented with one of three alternative representations of a given stimulus and were required to state whether or not that stimulus was present in a previously memorized list. For each type of stimulus representation and each response (positive or negative), reaction time was recorded. Functions relating reaction time to the size of the memorized list were both qualitatively and quantitatively different from those usually obtained with the Sternberg paradigm. In particular, the form of the functions did not correspond to predictions based on an exhaustive scanning process.     

An on site stress workshop for teachers: The creation of a therapeutic group environment

This paper describes an ongoing stress workshop conducted for 5 years in an elementary school. The school was located in an economically deprived area in the Bronx, New York. Similarities and differences between on-site workshops and therapy groups are discussed. The developmental stages of the group and its corresponding issues are analyzed in terms of group process, transference, and resistance. Illustrative vignettes are presented. The positive effects of group dynamic and group therapy interventions on the participating group as well as on nongroup personnel is demonstrated. Suggestions for adapting group therapy methods in school settings are also presented.This paper was presented as a poster at the Annual Conference of the American Group Psychotherapy Association held in Atlanta, Georgia, February 1995.