Effects of reinforcement schedule on facilitation of operant extinction by chlordiazepoxide

Learning and memory are central topics in behavioral neuroscience, and inbred mice strains are widely investigated. However, operant conditioning techniques are not as extensively used in this field as they should be, given the effectiveness of the methodology of the experimental analysis of behavior. In the present study, male C57B1/6 mice, widely used as background for transgenic studies, were trained to lever press on discrete-trial fixed-ratio 5 or fixed-interval (11 s or 31 s) schedules of food reinforcement and then exposed to 15 extinction sessions following vehicle or chlordiazepoxide injections (15 mg/kg i.p., administered either prior to all extinction sessions, or prior to the final 10 extinction sessions). Extinction of operant behavior was facilitated by drug administration following training on either schedule, but this facilitation only occurred once a number of extinction sessions had taken place. The extinction process proceeded more rapidly following fixed-interval training. Resistance to extinction was equally high following training with either schedule type, and was reduced by drug administration in both cases. These phenomena were evident in individual cumulative records and in analyses of group data. Results are interpreted in terms of phenomena of operant extinction identified in Skinner's (1938) Behavior of Organisms, and by behavioral momentum theory. These procedures could be used to extend the contribution of operant conditioning to contemporary behavioral neuroscience.     

A simplified technique for scoring DSM-IV personality disorders with the Five-Factor Model

The current study compares the use of two alternative methodologies for using the Five-Factor Model (FFM) to assess personality disorders (PDs). Across two clinical samples, a technique using the simple sum of selected FFM facets is compared with a previously used prototype matching technique. The results demonstrate that the more easily calculated counts perform as well as the similarity scores that are generated by the prototype matching technique. Optimal diagnostic thresholds for the FFM PD counts are computed for identifying patients who meet diagnostic criteria for a specific PD. These threshold scores demonstrate good sensitivity in receiver operating characteristics analyses, suggesting their usefulness for screening purposes. Given the ease of this scoring procedure, the FFM count technique has obvious clinical utility.     

Book reviews

Time's Arrow and Archimedes’ Point: New Directions for the Physics of Time Huw PRICE, 1996 New York, Oxford University Press xiii + 306 pp. SCAN 37.00 (hardcover) ISBN 0–19–510095–6

Mental Reality GALEN STRAWSON, 1994 Cambridge, MA, The MIT Press xiv + 337 pp., S37.50 (cloth), $17.50 (paper) ISBN 0–262–19352–3 (paper)

The Rule of Reason: The Philosophy of Charles Sanders Peirce JACQUELINE BRUNNING & PAUL FORSTER, Eds, 1997 Toronto, University of Toronto Press 316 pp., $80.00 (hardcover), $24.95 (paperback) ISBN 0–8020–0829–1 (cloth), ISBN 0–8020–7819–2 (paper)

Scientific Knowledge: A Sociological Approach BARRY BARNES, DAVID BLOOR & JOHN HENRY, 1996 Chicago, University of Chicago Press xvi + 230 pp., ISBN 0–226–03730–4 (cloth), 0–226–03713–2 (paperback)

The Scientific Revolution STEVEN SHAPIN, 1996 Chicago, University of Chicago Press x + 218 pp., ISBN 0–226–75020–5 (cloth), 0–226–75021–3 (paperback)     

Separate Digits tests: A brief history,a literature review,and a reexamination of the factor structure of the test of memory and learning (TOMAL)

Following a brief history of Digit Span, a review of 27 articles, selected from 76, addresses the question of whether to scale Digits Forward and Backward separately. The review begins with studies involving Digits Forward, followed in turn by studies of Digits Backward and of both subtests. Finally, the loadings of four TOMAL subtests, Digits Forward and Backward and Letters Forward and Backward, undergo examination in the context of two, three, and four factor promax solutions, with corresponding varimax solutions provided for comparison. The analysis leads to several conclusions. Though Digits Forward and Backward show similarities, they load differently in the three and four factor solutions; Digits Backward also displays a spatial element, and perhaps a transformative element, not apparent in Digits Forward. Moreover, the differences between the two measures have important neurologic and diagnostic implications.     

An object-oriented simulation of anorexia based on brain structure interaction

A computer simulation using an object-oriented strategy was developed to model brain mechanisms that underlie eating disorders. The simulation was based on neuroanatomical and neurochemical evidence from published literature. Testing of the simulation required that the activity levels of the raphe nuclei of the brain stem be altered and the resulting activity levels of associated brain structures be compared with results from human and animal data. The results supported the serotonin hypothesis of anorexia that increasing the activity level of the raphe nuclei would result in dramatic changes in the activity level of the paraventricular nucleus. The findings are discussed with respect to the feasibility of computer simulations to test theories of brain-based disorders.     

Emphasis as a prompt for verbal imitation

Four- and five-yr-old disadvantaged children were read sentences composed of varying numbers of short phrases. The children were asked to repeat each sentence, but the accuracy of their imitations was not differentially reinforced. The teacher stressed (emphasized) certain words as she read each sentence. The proportion of words that were stressed was systematically varied. In general, the children imitated only parts of most sentences. Stress was effective in influencing which parts of a sentence the children would imitate, but only when relatively few words were stressed. Stressing a word increased the probability of a child's imitating that word (and, to a large extent, the entire phrase containing that word) as an inverse function of the proportion of the words that were stressed.     

Effect of contingent and non-contingent social reinforcement on the cooperative play of a preschool child

The effect of adult social reinforcement on the cooperative play of a five-year old girl in a preschool setting was assessed under two conditions: (1) presented randomly throughout the school day, and (2) presented contingent on cooperative play. Only in the latter condition was a significant change in cooperative play observed.