Strategies of rule discovery in an inference task

It has long been known that subjects in certain inference tasks will seek evidence which can confirm their present hypotheses, even in situations where disconfirmatory evidence could be more informative. We sought to alter this tendency in a series of experiments which employed a rule discovery task, the 2-4-6 problem first described by Wason. The first experiment instructionally modified subjects confirmatory tendencies. While a disconfirmatory strategy was easily induced, it did not lead to greater efficiency in discovering the rule. The second experiment introduced subjects to the possibility of disconfirmation only after they had developed a strongly held hypothesis through the use of confirmatory evidence. This manipulation also failed to alter the efficiency of rule discovery. In the third experiment, subjects were taught to use multiple hypotheses at each step, in the manner of Platt's “Strong Inference”. This operation actually worsened performance. Finally, in the fourth experiment, the structure of the problem was altered slightly by asking subjects to seek two interrelated rules. A dramatic increase in performance resulted, perhaps because information which in previous tasks was seen as merely erroneous could now be related to an alternative rule. The four studies have broad implications for the psychological study of inference processes in general, and for the study of scientific inference in particular.     

Teacher reactions to school-based consultation services: A multivariate analysis

The impact of consultation services on teachers' preferences for consultation versus referral approaches and upon teachers' perceptions of severity for common acting out, withdrawal, and academic types of student problems were investigated. The subjects were 96 teachers whose public and parochial schools were matched and randomly assigned to treatment and control groups. Following a 14-week period during which advanced school psychology graduate students served as consultants in the treatment schools, the Pupil Problem Behavior Inventory (PPBI) was administered to all teachers. The results of a repeated measures MANOVA analysis indicated that the teachers in the treatment group rated the acting out and academic problems on the PPBI as significantly less severe than did teachers in the control group. The subjects in both the treatment and control groups indicated a significant preference for consultation rather than referral services for all types of student problems presented in the PPBI. There was a moderate, positive correlation between perceived problem severity and teacher preference for referral rather than consultation services. The study's results were interpreted as supportive of the consultation model.     

Teaching awareness of strategic behavior in combination with strategy training: Effects on children's memory performance

The present study examined the effectiveness of two components (rehearsal training and strategy awareness) of an instructional package designed to train the developmentally young in the use of mature information processing techniques. Two groups of children of equivalent developmental age (MA = 8), one mildly retarded and the other of average intelligence, participated. Rehearsal training was effective in improving recall scores on the training task; however, neither rehearsal training, memory awareness, nor their combination significantly altered memory performance on the generalization tasks. There was evidence, however, that the combination of rehearsal training and strategy awareness did increase the likelihood of strategy transfer on the generalization task (recognition) which most closely resembled the training task. Post-task questioning revealed that instructions concerning memory awareness did improve subjects ability to verbalize appropriate strategic behavior; however, these improvements were not consistently translated into either actual use of a rehearsal strategy or improved performance. Discussion centered on the implications of these results and on the need for increased research on the metamnemonic skills involved in strategy generalization.     

Programmed stuttering therapy for children: Comparison of four establishment programs

Four different establishment programs (programmed traditional, delayed auditory feedback, pause, and gradual increase in length and complexity of utterance) for improving the fluency of school-age children who stutter were compared. The programs were carried out by eight public school clinicians with 16 children (eight elementary and eight junior-senior high school) in their respective schools. All four programs produced important improvement in the speech fluency of the 16 children. All the children demonstrated transfer of fluency to extratraining settings. The delayed auditory feedback program required the least therapy hours, but it was difficult for the clinicians to operate correctly. The gradual increase in length and complexity of utterance programs produced the best overall results. The transfer and maintenance programs provided for additional generalization and permanency of fluency. Follow-up revealed that the children continued their increased level of fluency.     

Mouse killing in rats induced by lesions of the medial hypothalamus or medial accumbens: short-term preoperative exposure to a mouse does not suppress the killing

Rats were either exposed or not exposed to a mouse in their living cage for a 48-hr period. At the end of this time a bilateral lesion was made in the medial accumbens region or in the medial hypothalamus. When tested 2 days postoperatively, the killing frequency among rats that had been exposed to mice preoperatively was not significantly lower than that of rats that were not preoperatively exposed. The ineffectiveness of preoperative experience in suppressing the mouse killing induced by medial accumbens and medial hypothalamic lesions is similar to that found previously with dorsal-median raphe lesions and olfactory bulb lesions and is in contrast to the ease with which preoperative experience prevents mouse killing induced by septal lesions and serotonergic lesions induced by 5,7-dihydroxytryptamine.     

The use of the psychological stress evaluator with stutterers

A lie detection instrument, the Psychological Stress Evaluator, has been reported by the manufacturer as being capable of quantifying changes in the degree of “stress” as reflected by a subject's voice. Speech pathologists might consider the use of the instrument in clinical and research activities concerning the stutterer's emotional (stress) reaction to stuttering.To test the validity of the instrument, four stutterers and four normal speakers were recorded while making consecutive telephone calls. Randomized recordings were analyzed by a company trained technical to determine the degree of stress for each speech sample.Results indicated that both groups had a significant reduction of stress from the first to the fourth telephone call. However, the groups did not differ in the degree of stress during the ordered series of calls. Due to the inability of the Psychological Stress Evaluator to differentiate between the groups, the validity of the instruments is questioned.     

Accuracy in the judgment of in-group and out-group variability

The accuracy of in-group and out-group variability judgments was examined by comparing those judgments with the variability of self-ratings provided by random samples of group members. Following Park and Judd (1990), perceptions of both group dispersion and group stereotypicality were examined. Accuracy was examined both by within-subject sensitivity correlations and by simple discrepancies between perceived and actual variability estimates. In-group-out-group differences in sensitivity were shown, particularly for judgments of stereotypicality. These differences were related to differences in the degree to which out-group variability is underestimated relative to in-group variability (i.e., the out-group homogeneity effect). Out-group stereotypicality judgments were overestimated, supporting the view that out-group stereotypes are overgeneralizations. Whether dispersion judgments were over- or underestimated depended on their measurement.     

Appearances can be deceiving

Conclusion I began by claiming that I simply wanted to undermine the plausibility of the appeal to appearances in matters of perceptual belief. Most of the arguments I have offered, however, have been more strongly stated, viz., I have apparently tried to eliminate them rather than simply render them less credible. But the notion of appearances is deeply entrenched, so much so that simply undermining their credibility may require overstating the case somewhat. The central theme of the above arguments is that appealing to appearances misleads us. The appeal misleads us into giving the wrong sorts of explanation, both with respect to the psychology of perceptual belief formation and the justification of perceptual beliefs. In short, appearances can be deceiving. And they probably are.A distant (if now unrecognizable) ancestor of this paper was first read at the 12th Annual Louisiana Philosophy Convention in October, 1988. Steve Fuller also offered comments on an intermediate version. I am especially grateful to Norton Nelkin who has read and commented on several versions. He should not be held complicit, however.