The role of individual differences in sandbagging on selective avoidance of self-evaluative information

In the current experiment (N = 86), I evaluated the hypothesis that high and low sandbaggers differ in their preference for self-evaluative information. Results demonstrate that low sandbaggers sought accurate self-assessment information in private and in public, but high sandbaggers bypassed such information when it would be made public. These data support the notion that high sandbaggers are self-protective and tend to focus on social evaluation, while low sandbaggers seek accurate self-assessment regardless of the potential for social evaluation. Furthermore, data help to distinguish between sandbagging and self-handicapping. Discussion focuses on the motivation of sandbaggers, along with how this motivation differs from that of self-handicappers.     

Pigeons and people select efficient routes when solving a one-way "traveling salesperson" task

The authors presented people (Experiment 1) and pigeons (Experiments 2 and 3) with a large number of 1-way traveling salesperson problems that consisted of 3, 4, and 5 identical stimuli (nodes) on a computer monitor. The sequence of nodes that each traveler selected was recorded, and the distance of the route was subsequently determined. The routes the pigeons and people selected were reliably more efficient than those used by a Monte Carlo model given the same problems. The pigeons' routes were significantly less efficient than a nearest neighbor model of performance, however. In Experiment 3, pigeons were required to select a route that was within the top 33% of all possible solutions for a given problem. The pigeons' solutions were significantly more efficient than those observed in Experiment 2, in which the behavioral criterion was not imposed. The mechanisms that pigeons and people may have been using to solve the traveling salesperson problems are discussed.     

False physiological feedback and emotion: Experimenter demand and salience effects

Four experiments examined the hypothesis that the Valins (1966) false physiological feedback effect with attractiveness ratings of slides is due to experimenter demand. Experiments 1 and 2 showed significant feedback effects with 5-sec feedback periods, previously reported by Barefoot and Straub (1971) to be too brief a time to search the slides for a cause of the apparent physiological arousal. Experiments 3 and 4 had 17 variations of instructions (emotional, nonemotional), stimuli (slides of people, scenic tourist slides), and type of feedback information (heart rate, eyeblink, or none). The typical false feedback effect was found under many conditions that did not seem to meet the presumptive attributional requirements for the effect. In Experiment 4, only subjects who said they were supposed to rate feedback slides higher showed the effect, regardless of instructions, stimuli, or type of feedback. The overall results are interpreted in terms of experimenter demand and stimulus salience effects.     

Bilateral transfer in mentally retarded children of ages 7 to 17 years

The purpose of this study was to describe the effect of age on bilateral transfer of mildly mentally retarded girls (IQs of 70 to 90) after practice on a 45-rpm rotary pursuit task. Subjects were 96 girls from 7 to 17 yr. old. Each performed 14 trials on a rotary pursuit task (30-sec. trials, 10 sec. between trials), half performing the first seven trials with the nonpreferred hand, using the preferred hand on the next seven trials. The order was reversed for the remaining subjects. Nonsignificant differences between Trial 1 scores of the two groups indicated that the task was novel. Trial 1 scores of both groups were positively associated with age (r = 0.5). There was no transfer to preferred hand, with negative transfer occurring to the nonpreferred hand. It was concluded that, for the task used in this study, mentally retarded girls do not experience positive bilateral transfer as do normal, age-matched girls.     

Using digitized auditory stimuli on the Macintosh computer

Hardware/software packages that digitize sound on the Apple Macintosh can help researchers prepare and present auditory materials needed for their experiments. Common features and benefits of commercially available sound digitizing packages are discussed in terms of some possible applications to cognitive psychology experiments.     

Differences in matching-to-sample performance with element and compound sample stimuli in pigeons

This series of experiments examined zero-delay matching-to-sample performance in pigeons with element and compound sample stimuli. In Experiment 1, compound sample stimuli were consistently followed by compound comparison stimuli and matching accuracy during testing was equivalent to element sample-element comparison trials on the color dimension. In Experiment 2, element comparisons suddenly introduced following compound samples produced a decrement on the line dimension only. Subsequent testing at various sample durations revealed higher matching accuracy following element samples than following compound samples on both the color and line-tilt dimensions. Experiment 3 replicated the results of Experiments 1 and 2 and also demonstrated that the superiority of element over compound matching performance remains constant over the sample durations tested. In Experiment 4 testing at sample durations up to 30 sec produced an overall decrement in matching performance, but again the element vs compound matching difference remained constant. The stimulus-generalization decrement hypothesis provided a better explanation of these results than either the information-overload hypothesis or the rule hypothesis.     

Extending latent class solutions to other variables

A procedure is derived for estimating the latent parameters of items not initially included in a latent class solution, on the assumption that the relations between those additional items and the original ones are accounted for by the same latent structure. A chi-square test is proposed for evaluating the relatedness of the additional items to the latent structure. The extension is generalized to associate continuous outside variables with the original solution, and this is accompanied by the suggestion that a simple analysis of variance be used to assess the results. Finally, this latent structure extension is compared with the Dwyer extension of factor analysis.I am grateful to J. J. Mellinger for clarifying discussions of the statistical portions of this paper.Opinions expressed herein are the author's, not the Army's.