Tactile short-term memory

Subjects tried to recall the location of a tactile stimulus on the underside of the forearm after delays of 0, 3, 5, 10, 15, 30, 45 and 60 sec. When “rehearsal” was prevented by requiring subjects to count backwards during the delay, accuracy of recall decreased systematically reaching an asymptote after 45 sec. When subjects were left free to “rehearse,” this did not affect the decline in accuracy over the first 10 sec. Between 10 and 15 sec. there was a significant increase in accuracy followed by a slow decline which had not reached asymptote by 60 sec. It is suggested that tactile STM (short-term memory) depends on two processes, a fading sensory trace which is unaffected by distraction and a less labile system which does not appear to be verbal but which depends on “rehearsal.”     

A model for detection and recognition with signal uncertainty

A model for signal detectability suggested by Luce is extended to situations in which the observer is uncertain of some important characteristic of the signal, such as frequency. By making a single assumption concerning the observer's covert response behavior, two solutions are obtained corresponding to qualitatively different behavior. Decrements in detectability and in recognition with uncertainty are shown to be particular functions of discriminability and detectability of the stimuli in other situations. Relevant experimental data are considered.This work was supported by grant NSF-G5544 from the National Science Foundation. The author is indebted to R. Duncan Luce for critical discussion of the content and helpful suggestions concerning the form of this paper. Useful comments have been made by David M. Green, Francis W. Irwin, Roger M. Shepard, and W. P. Tanner, Jr.     

A note on further experiments on the effects of meprobamate on discrimination performance in the monkey

A previous experiment (Gross and Weiskrantz, 1961) has shown that performance on a successive auditory discrimination task is impaired by injections of meprobamate. The present two brief experiments indicate that the drug also impairs simultaneous visual discrimination performance, although not to the same degree as found earlier for auditory discrimination. The original finding, therefore, cannot be attributed simply to unique features of the auditory discrimination situation, such as the “go—no-go” response contingency. Since neither overtraining nor drug habituation appears to be of great importance, it is suggested that the lesser effect of the drug in these experiments reflects the greater stability of visual than auditory habits in the monkey.

Earlier work has shown that meprobamate and reserpine can cause a severe deterioration in auditory discrimination performance of monkeys (Gross and Weiskrantz, 1961). This result was taken as supporting a hypothesis, growing out of still earlier research, that tranquillizers decrease the utilization of sensory information (Weiskrantz and Wilson, 1956; Weiskrantz, 1957).

The auditory task, as is almost always the case with monkeys as subjects, involved a “go—no-go” type of response contingency—i.e. the animal had to respond to the positive stimulus and had not to respond to the negative stimulus in order to achieve reward. It might be objected, therefore, that the deterioration in performance was associated not with discrimination as such but with the animals' willingness to perform at all. In fact, it was found that the animals tended to make most of their errors under the drugs by responding when they should not rather than not responding when they should.

The purpose of the present experiments, therefore, was to test the animals with a visual discrimination task in which both the positive and negative stimuli were presented simultaneously. An effect of the drug could not, in this situation, be characterized simply as altering the responsiveness of the animal. A further purpose in using visual stimuli was to test the generality of the earlier finding in a sense modality other than audition.     

Behavioral case formulation: An experimental assessment study of transient tic disorder

A nine-year-old male, who met DSM III-R criteria for transient tic disorder, participated in an experimental assessment strategy to generate support for a case formulation. In addition to presenting motor disturbance, assessment procedures revealed six problem areas. All problems were formulated as manifestations of a hypersensitivity to evaluation, etiologically related to the boy's relationship with an insecure and critical father. It was hypothesized that the patient's tic disorder was a consequence of his hypersensitivity to father's excessive criticism, which then generalized to other evaluative situations. Using a controlled single-subject design, predictions derived from the formulation were tested by exposing the child to a planned combination of evaluative observers (e.g., father, mother, therapist, etc.) who watched him as he worked on a series of puzzles. The dependent measures included (1) behavioral recordings of tic frequency and (2) frontalis EMG responses. The results indicated significant differences in tic rate and EMG as a function of the type of observer. Consistent with the formulation, the patient displayed the highest levels of tic behavior and EMG response when his father was the observer and lowest in the presence of the mother. Predictions regarding other stimulus conditions were also confirmed. These results provided support for the case formulation that was used to design an effective treatment intervention. Findings suggest that the case formulation model offers a method whereby novel case hypotheses can be generated for poorly understood psychopathology and tested later in the experimental situation.     

The etiology of schizophrenia as perceived by psychiatrists in Europe and the United States

This paper compares and contrasts statements made by American and European psychiatrists on the etiology of schizophrenia. In the U.S., leading figures in psychiatry hold increasingly to the view that the disorder is physiogenic at source—from which it seems to follow that the appropriate treatments should similarly focus on physiological and pharmacological therapies. In contrast, European psychiatrists seem to be divided in support for organic and psychodynamic explanations. Some European writers have pointedly warned against over-interpreting recent studies which seem to point to specific organic dysfunctions and deficits as schizophrenogenic. This paper was presented at the Second Annual Convention of the American Psychological Society, Dallas, Texas, June 7–10, 1990.     

The prediction of adjustment at age 7 from activity level at age 5

One-hundred and ninety-two children (equally split between boys and girls) were studied when they were 5 years old in two settings, school and home. The children were observed in playgroups and at home, and were rated on activity level by their parents on the Rothbart Child Behavior Questionnaire. At age 7, the children were tested in our laboratory on the Harter Test of Perceived Competence and on an achievement task, and parents filled out the Child Behavior Checklist, the Child Behavior Questionnaire, and the Conners Parent Rating Scale. Home observations of activity level were significantly related to parent ratings of activity level, but not to school observations. Activity level at age 5 was related to parents' ratings of aggression and hyperactivity and to girls' learning problems at age 7. Activity level was not related to the children's self-perceived competence, but mothers' rating of high activity level at age 5 was related to low reading comprehension at age 7.Preparation of this paper was supported in part by the Center for Research for Mothers and Children, NICHD, U.S. PHS grant HD 19739 to Beverly I. Fagot.     

Naming consistency in Alzheimer''s disease

Although lexical semantic deficits are postulated to play a prominent role in the anomia of Alzheimer's disease, it is unclear whether the primary disturbance is one of lexical access or one of lexical semantic loss. Response consistency on a naming task is one means of evaluating the underlying source of naming impairment. Access dysfunction usually implies variable word-finding difficulty, while a theory of lexical loss predicts that many word names would be consistently unavailable. Nineteen Alzheimer's disease patients were administered a visual confrontation naming task (the Boston Naming Test) on two occasions 6 months apart. Eighty percent of errors occurred consistently at both times; only 20% of errors occurred on only one occasion. Response consistency occurred significantly more often than expected under the assumption of no response consistency. Findings support the hypothesis that anomia in Alzheimer's disease is in part due to a loss of lexical semantic information.