Behavioral assessment of pain detection and tolerance in monkeys

Cebus albifrons monkeys received electrical stimulation of the hindlimbs over a wide range of intensities. On trials signalled by a blue light, the animals were permitted to escape shock by pressing a disc, or shock was terminated after 8 sec (free escape). Escape force (disc pressure) was found to increase as stimulation intensity increased well beyond escape threshold, while shock duration curves reached plateau at the mid-range of intensities. The shock duration curves generated by free escape responses should be comparable to pain detection functions obtained by similar operations in humans, and the curves were stable over months of testing, as is generally found in pain-detection studies. On trials signalled by a red light, the animals received intense tail shock immediately after escape responses (punished escape), or, if they endured leg shock for 8 sec without escaping, then they could avoid tail shock with a panel press. The shock duration curves generated by punished escape responses should be comparable to pain tolerance functions as defined for human subjects, and the escape thresholds were considerably higher on red-light trials. As in human studies, the tolerance curves were not stable over repeated testing sessions, and some feature of the paradigm forced a progression toward extremely high levels of tolerance.     

Differcntial feature analysis in the recognition memory of reflective and impulsive children

Seventy-two children. 18 reflective, and 18 impulsive first and fifth graders were tested in a forced-choice recognition memory task. Experimental conditions systematically varied the possibility that correct responses could be made on the basis of verbal labels, visual feature analyses, or both. Although reflective children made more correct recognition choices than did impulsive children under all experimental conditions, this difference was, as predicted, significant only in a condition in which the sole basis for correct response depended on a purely visual feature analysis. Order of condition difficulty indicated that visual feature analysis independent of verbal processes was responsible for successful recognition performance in these Ss. Results were discussed with reference to the feature-testing model for recognition proposed by Selfridge and Neisser.     

Measuring the Ponzo illusion with the method of production

The Ponzo illusion was varied as a function of angle of oblique arms and was measured by the method of production. The results showed that the method of production produced very similar results to those obtained by the method of limits. The data also indicated that relatively stable individual scores could be obtained if about six judgments were required and if the targets elicited a large illusion. It was concluded that the method of production should be given serious consideration when choosing a psychophysical method.     

Visual recognition memory in reflective and impulsive children

Twenty-nine reflective and 29 impulsive fifth-grade boys were tested in a forced-choice visual recognition memory task. In three of the experimental conditions (1FD, 2FD, 4FD) the number of visual feature differences between the correct and incorrect test stimuli was 1, 2, or 4, and correct response could not be based on the name of the stimulus; in the fourth condition (DO) the correct and incorrect test stimuli had different names. As predicted, performance on DO and 4FD was equivalent and was superior to that on 1FD and 2FD. Although reflective Ss made more correct responses than impulsive Ss in all four conditions, only the performance difference in Condition 1FD was significant. Mean correct response latencies mirrored the correct response data. These results were consistent with the Selfridge-Neisser feature-testing model of recognition memory, and it was argued that the primary underlying basis for the dimension of reflection-impulsivity was that reflective Ss tend to engage in a more detailed visual feature analysis of stimulus arrays. Strong inferential evidence was provided that visual feature analysis independent of verbal labeling was responsible for successful recognition performance in these Ss.     

Further developments in the assimilation theory of geometric illusions: The adjacency,principle

It is argued that the parallel lines illusion is the basic model for many visual distortions that are produced by geometric patterns. An experiment assessed the effect of moving the contextual contour away from the standard contour in two directions—away from the center of the attentive field and toward the center of the attentive field. The degree of illusion declined as the contextual magnitude moved away from the standard magnitude, but the rate of decline was more rapid when the contextual stimulus was moved away from the center of the attentive field. The results necessitated the addition of a new postulate for the assimilation theory of geometric illusions. This postulate states that the effectiveness of a contextual magnitude decreases as the distance between the contextual magnitude and the standard magnitude increases. The postulate was translated into a mathematical form in a manner analogous to the way in which the “attentive field” postulate was quantified. The new formula was successful in predicting both the pattern of means and the pattern of variances found in this study. The formula was cross-validated with data from the Ponzo and reversed Mueller-Lyer illusions.     

Reviews of books

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Reviews of books

     

Picture-word differences in decision latency: An analysis of single and dual memory models

Semantic and perceptual size decision times for pictorial and verbal material were analyzed in the context of a unitary memory model and several dual memory models. Experiment 1 involved a same-different categorical judgment task. The results showed that picture-picture response latencies were 185 msec faster than the corresponding word-word latencies, and word-picture and picture-word latencies equaled the mean of these two extremes. Similarity of subcategory for “same” judgments led to faster decision latency for all presentation conditions. Additionally, a linear relationship was found between picture-picture and word-word latencies for individual item pairs. Experiment 2 involved a comparison of pictures and words across a. categorical judgment and a size judgment task. Pictures produced faster decision latencies in both tasks, and the latency diflerence between pictures and words was comparable across tasks. These data fit the predictions of a unitary memory model. Several variants of a dual memory model are rejected and those which fit the data require assumptions about storage and/or transfer time values which result in a functional regression to the unitary memory model.     

Learning of a complex arithmetic skill in amnesia: evidence for a dissociation between compilation and production

Two patients with severe amnesia following rupture of anterior communicating artery aneurysms were able to learn a complex algorithm for mentally squaring two-digit numbers. Although both patients learned the algorithm at a similar rate, one patient's improvement was accounted for by savings in the steps of the algorithm. The other patient, however, showed little improvement in the steps while performance of the whole algorithm improved dramatically. Neither patient showed savings in the Hebb Digit Span procedure. The results suggested a dissociation between amnesics in their capacity to learn the constituent "productions" or steps of a skill and their capacity to organize those productions into a single coherent act.