The dilution effect: Nondiagnostic information weakens the implications of diagnostic information

In a series of studies, subjects were asked to make predictions about target individuals. Some subjects were given information about the target which pretest subjects had judged to be “diagnostic”—that is, had judged to be usefully predictive of the outcome. Other subjects were given a mix of information judged to be diagnostic and information judged to be “nondiagnostic” by pretest subjects—that is, judged to be of little value for predicting the outcome. Subjects given mixed information made much less extreme predictions than did subjects given only diagnostic information. It was argued that this “dilution effect” occurs because people make predictions by making simple similarity judgments. That is, they compare the information they have about the target with their conception of outcome categories. The presence of individuating but nondiagnostic information about the target reduces the similarity between the target and those outcomes that are suggested by the diagnostic information. One of the major implications is that stereotypes and other “social knowledge structures” may be applied primarily to abstract, undifferentiated individuals and groups and may be largely set aside when judgments are made about concrete, individuated people.     

Sensitivity of 5- and 7-month-old infants to pictorial depth information

An Ames (1951, Psychological Monographs, 65(1, Whole No. 324)) static trapezoidal window, under monocular view, was used to test young infants' responsiveness to pictorial depth. When adults view this display monocularly with the smaller side of the window rotated toward them, they report that the orientation of the display becomes ambiguous: When the head is moved, the window may appear to be in the fronto-parallel plane or either side may appear closer. The 7-month-olds we tested appeared to experience a similar ambiguity; they reached to the near side of the rotated trapezoidal window with significantly less consistency or directedness than infants in a control group tested with a rotated object that lacked pictorial depth information. When 5-month-olds were tested, however, they reached with equal consistency to the closer side of the trapezoidal window and of the control display, apparently uninfluenced by the pictorial depth information available in the trapezoidal window. Thus, sensitivity to the pictorial information for depth that is present in the trapezoidal window appears to develop after the age of 22 weeks.     

Performance of dyslexic children on speech perception tests

Several researchers who have compared the performance of dyslexic and normal-reading children on a variety of different tasks have suggested that dyslexic children may have subtle deficits in the phonemic analysis of spoken as well as written language. Thus it is of interest to know how children who have extraordinary difficulty learning to read can perform explicity auditory-phonetic tasks. Seventeen dyslexic children (10 years of age) and a group of 17 controls were administered tests of identification and discrimination of synthesized voiced stop consonants differing in place of articulation. These were tests of the type used to study categorical perception in adults, adapted for use with young children. Significant differences between dyslexics and controls were found in both kinds of tasks; the pattern of identification and discrimination differences suggests an inconsistency in the dyslexics' phonetic classification of auditory cues. A significant relationship was found between reading level and speech discrimination.     

The effect of modification of expressive displays on vicarious emotional arousal

Several recent experiments have demonstrated that modulation of the facial expressive response is accompanied by changes in autonomic arousal and subjective response to painful stimuli. The present study asked whether facial self-regulation may also bring about changes in covert vicarious emotional experience. Three groups of subjects were exposed to a videotaped model displaying intermittent pain to shock in a differential vicarious autonomic conditioning paradigm. Subjects in the inhibit and amplify groups were asked, respectively, (a) to inhibit their facial muscles or (b) to pose a facial response of pain when the model was shocked. It was predicted that the inhibit group would show less autonomic arousal to the model's expressive display (empathy) and less conditioning (as measured by skin conductance and heart rate change), and the amplify group more empathy and conditioning, than a third group who was given no facial instruction. In fact, the amplify group showed more skin conductance arousal, heart rate acceleration, and activity in response to the model's expressive display of pain than did the other two groups (which were not different from each other), but no more autonomic or facial conditioning. The overall pattern of physiological data is interpreted as generally supportive of a facial feedback theory of emotion: where significant between-groups' differences were obtained in facial activity, as in vicarious instigation, autonomic arousal differences also emerged; where no expressive differences were obtained, as in vicarious conditioning, no differences in autonomic arousal were found.     

The psychometric attributes of Furth's nonverbal conservation test

The study examined the suitability of Furth's nonverbal conservation test as a psychometric tool for measuring individual differences in Zambia. The subjects included normal and mentally deficient Zambian children aged 7–13 years. The test was validated against age differentiation, differentiation of different intellectual levels, and school performance. The results showed that scores on the test increased significantly with increase in age, correlated positively and significantly with school scores, and differentiated normal from mentally deficient children. Within the normal sample the test also differentiated dull from average children; within the deficient sample the test did not differentiate the moderately mentally deficient from the severely mentally deficient. These results are explained by reference to the characteristics of the test, performance on which requires learning, memory, and perceptual abilities.     

On the form and location of the Psychometric Bisection Function for time

The Psychometric Bisection Function for time relates the discriminability of intermediate duration stimuli to a short and long training duration. Bisection Functions for animals (R. M. Church & M. Z. Deluty, Journal of Experimental Psychology: Animal Behavior Processes, 1977, 3, 216–228) confirm Weber's Law and also show indifference between short and long reports at the geometric mean of the training durations. Two discrimination processes are studied which, in combination with different constructions of the subjective time scale, result in Bisection Functions which differ in form and location. The two discrimination processes use a likelihood ratio rule or a similarity rule to compare intermediate durations to the training durations. These rules in combination with two different constructions of the subjective time scale result in four models which conform to Weber's Law. For one of the scales subjective time is a power function of real time with the scalar property on variance (Scalar Timing). For the other, subjective time is a logarithmic function of real time with constant variance (Log Timing). Both Log and Scalar Timing assume normality on the subjective scale. Only three of these models also entail the geometric mean at the indifference point. The exception is Scalar Timing with the likelihood ratio discrimination rule. This model entails indifference at approximately the harmonic mean of the training stimuli. Variants of the remaining three models differ theoretically but alternatives are difficult to discriminate empirically. A contrast is provided by a Poisson Timing subjective scale in which variance increases directly with the mean. This scale results in indifference at the geometric mean for both discrimination rules but violates Weber's Law in both cases.     

Atttudes and behavior: Implications of attitudes toward behavioral alternatives

The relationship between attitudes and behavior was considered. An attitudinal model of behavioral alternatives was presented and its applied and theoretical implications explicated. Three investigations were reported that tested the initial viability of the approach. Support for the model was observed in all three investigations.     

Postdecision evaluation of choice alternatives as a function of valence of alternatives,choice, and expected delay of choice consequences

The effects of valence of alternatives, choice, and expected delay of choice consequences on postdecision evaluations of choice alternatives were studied by either giving subjects a choice between two experimental tasks (both either pleasant or unpleasant) or assigning subjects their initially preferred task. Crosscutting valence and choice, subjects expected either no delay, 10-min delay, or 30-min delay before engaging in the task. All subjects evaluated both tasks immediately after the delay instructions but before experiencing the actual delay. Results confirmed the expected dissonance effect; that is, an upward evaluation of the chosen alternative and a downward evaluation of the rejected alternative, relative to no-choice conditions. Moreover, the relative upward evaluation of the chosen alternative increased as the expected delay decreased. Valence was not found to interact with other variables. The results are discussed in terms of differential salience of choice alternatives.     

Exercise, changes in aerobic capacity, and changes in self-perceptions: An experimental investigation

Subjects in an exercise training condition participated in a 10-week aerobic exercise class, whereas subjects in waiting-list control and independent control conditions did not. The results indicated that subjects in the training condition evidenced reliably greater improvements in physical fitness (aerobic capacity) and reported reliably greater improvements in their abilities and confidence in both the physical area (e.g., ability to run distances) and nonphysical area (e.g., frustration tolerance) than did subjects in the control conditions. On the other hand, improvements in physical fitness were not related to reported improvements in abilities and confidence. These findings are of interest because they indicate that some of the important personal changes that are associated with physical fitness training are not due to changes in fitness, but appear to be due to other factors (e.g., group participation and expectancies).