Reliability of multiple classifications

Cohen's kappa index is reformulated for multiple classifications based on exchangeable random variables. It is found that kappa is between 0 and 1 inclusive. Two characterizations for kappa are stated in terms of the relationship between such random variables. Within the normal test score model, kappa increases with test reliability and test length. Furthermore, when based on binary classifications, kappa is an inverse U-shaped function of the cutoff score. These trends also hold for the beta-binomial test score model.Paper read at the Spring meeting of the Psychometric Society, Bell Laboratories (Murray Hill, New Jersey), March 1976.The editorial assistance and helpful comments of Leonard S. Feldt, Sarah P. Seaman-Huynh, and the three referees are gratefully acknowledged.     

Further analysis of stuttering as a phonetic transition defect

This article presents a further analysis of stuttering as a phonetic transition defect. Three types of phonetic transitions are identified. Two of these occur within words and represent sites where stutterings are readily detectable. The third transition involves movement from the end of one word to the beginning of the next. Spectrographic evidence is provided to show that stuttering also occurs at points of transition of this type. The same data are interpreted relative to their implications for stuttering theory, research, and therapy.     

The universal nature of human intelligence: Evidence from games

Mentally retarded individuals have relatively greater difficulty in dealing with strategic games and puzzles than with many other tasks. Consequently, it is of interest to find that strategic games have been played since ancient times, are played throughout the world, and that players who excel are frequently considered wise. Hidden within the more obvious differences between cultures, strategic games are an invariant expression of certain universal intellectual traits.     

Influencesicture context on object recognition

The effect of sorrounding context on the recognition of objects from briefly presented pictures was investigated. Forty-eight undergraduates saw 100 msec displays of either line drawings containing several objects embedded in context or drawings of object arrays without background context. Following each exposure they were required to select from among four objects the one that had been contained in the picture. Presentation of objects in context aided recognition only when incorrect response alternatives were inconsistent with the picture context. The results suggest that context contributes to the construction of a general characterization of the pictures which provides expectancies regarding the identity of specific objects.     

Effects of erotic stimuli on sexually functional and dysfunctional women: Multiple measures before and after sex therapy

A group of 11 women entering sex therapy for treatment of low arousal, and a comparison group of 11 women experiencing no arousal deficit, viewed an erotic film, listened to an erotic audiotape, and engaged in sexual fantasy during two experimental sessions. Session I occurred pre-treatment for the low arousal group. Session II occurred post-treatment. The adequate arousal group was tested at comparable points in time. Sexual arousal was measured subjectively by self-rating and physiologically by a vaginal photoplethysmograph. Contrary to expectation, the two groups showed equivalent significant increases in physiological response during the erotic stimuli in both sessions. However, the adequate arousal group rated subjective arousal significantly higher than the low arousal group in Session I, while no difference was found between the groups in Session II. Significant correlations were present between physiological response and ratings of several affective reactions to the audiotape, though few significant correlations were found between physiological and subjective sexual arousal measures. These data indicate a discrepancy between genital responses and ratings of sexual arousal for which several interpretations are offered.     

Treatment of bisexual pedophilia by a biofeedback-assisted self-control procedure

A bisexual pedophile was treated for 88 days using a biofeedback procedure which displayed his erection response to sexually deviant stimuli on a closed-circuit television monitor. Told to develop a strategy of self-control using the biofeedback, his response to young boys and girls was treated sequentially in a multiple baseline design. His concurrent response to boys, girls and adult males was evaluated in separate generalization sessions. The treatment was successful in suppressing deviant response while maintaining nondeviant response in strength. Debriefing of the client following treatment revealed that he had used a self-developed technique of covert sensitization to suppress deviant response and had used the biofeedback to confirm and validate this self-control strategy.     

Suppression and substitution in the treatment of nailbiting

The effectiveness of a package treatment for reducing nailbiting was studied. The package was composed of both positive procedures aimed at teaching adaptive behavior to substitute for nailbiting and negative procedures aimed at advancing skills for suppressing nailbiting. The design of the study permitted an analysis of the contributions of both positive and negative components of the package. Subjects assigned to combined, positive, negative and placebo groups received four weekly treatment sessions, and changes in their nailbiting behavior were compared with untreated controls. As in previous studies, nonspecific factors such as demand and attention to ones nails were found to be important determinants of outcome. In addition, positive procedures were found to be substantially more important than negative procedures in the maintenance of reductions in nailbiting over a 4-month follow-up period.     

On the discriminability of stimulus duration.

The performance of pigeons trained to detect differences in the duration of stimuli was analysed using a matching model of signal detection. Two white stimuli, S1 and S2, differing in duration, were arranged with equal probability on the center key of a three-key chamber. S1 was systematically varied from 5 seconds to 25 seconds while S2 remained constant at 30 seconds. On completion of the center-key stimulus, a peck on the center key turned on the two red side keys. A left-key response was "correct" when S1 had been in effect on the center key and a right-key response was "correct" on S2 trials. A correct response produced a 3-second magazine light accompanied intermittently by food. Incorrect responses produced 3-second blackouts. Detection performance was measured under two procedures. In the first, the obtained reinforcement ratio was uncontrolled by allowing the number of food reinforcements obtained for correct left- and right-key responses to vary as the stimuli were changed. In the second procedure, the presentation of food reinforcement was controlled by holding the obtained reinforcement ratio constant. Discriminability changed as a function of stimulus differences under both procedures. No such trend was found in response bias.