Discrimination between outcomes in instrumental learning: Effects of preexposure to the reinforcers

In two experiments rats received instrumental training with two response levers, one response being reinforced by sucrose solution and the other by sucrose pellets. Prior to a test session, on which both levers were made available in the absence of reinforcement, the rats were given free access to one of the reinforcers, a procedure known to reduce its value. It was found that the rats responded at a lower rate on the lever that had produced the now-devalued reinforcer, but that this effect was substantial only in rats that had received preexposure to the two reinforcers before instrumental training was begun (Experiment 1). Experiment 2 demonstrated that this effect was obtained only when presentations of the two reinforcers were presented according to an inter-mixed schedule during preexposure. It is suggested that this result constitutes an instance of the perceptual learning effect in which intermixed preexposure to similar events enhances their discriminability.     

Book reviews

Bloom, A. H. The Linguistic Shaping of Thought : A Study of the Impact of Language on Thinking in China and the West. Hillsdale, N.J.: Erlbaum. 1981. Pp. 106. £9.95. ISBN 0 89859 089 2.

Fodor, J. A. Representations : Philosophical Essays in the Foundations of Cognitive Science. Brghton: Harvester. 1981. Pp. 343. £22.50. ISBN 0 85527 977 X.

Sanford, A. J. and Garrod, S. C. Understanding Written Language: Explorations in Comprehension Beyond the Sentence. Chichester: John Wiley & Sons. 1981. Pp. xiv + 224. £ 11.30. ISBN 0 471 27842 4.

Springer, S. P. and Deutsch, G. Left Brain, Right Brain. San Francisco: W. H. Freeman & Co. 1981. Pp. 243. £4.95 (paperback). ISBN 0 7167 1270 9.

Crystal, D. Introduction to Language Pathology. London : Edward Arnold. 1980. Pp. 214. ISBN 0 7131 62759. £5.50.

Hulme, C. Reading Retardation and Multi-Sensory Teaching. London : Routledge & Kegan Paul. 1981. £12.50. Pp. 200. ISBN 0 7100 0761 2.

Liben, I,. S., Patterson, A. R. and Newcombe, N. (Eds). Spatial Representation and Behaviour Across the Life Span. New York: Academic Press. 1981. Pp. 404. ISBN 0 12 447980 4. £17.80.

Coltman, D. Jean Piaget: Experiments in Contradiction. Chicago: University of Chicago Press. 1980. Pp. 310. ISBN 0 226 66779 0. £13.20.

Hofer, M. A. The Roots of Human Behavior. San Francisco: Freeman. 1981. Pp. xiii + 331. Paperback £6.70. ISBN 0 7167 1278 4.     

Experimental components analysis of brief theory-based HIV/AIDS risk-reduction counseling for sexually transmitted infection patients.

An experimental components analysis of brief HIV risk-reduction counseling based on the information-motivation-behavioral skills (IMB) model was conducted with 432 men and 193 women receiving sexually transmitted infection (STI) clinic services. Following baseline assessments, participants were randomly assigned to 1 of 4 90-min risk-reduction counseling sessions that deconstructed the IMB model within a full factorial design. Participants were followed for 9 months, with STI diagnoses monitored over 12 months. Men who received the full IMB session evidenced relatively greater use of risk-reduction behavioral skills and relatively lower rates of unprotected intercourse over 6-months follow-up and had fewer new STIs. For women, however, the motivational counseling demonstrated the most positive outcomes. Results suggest that brief single-exposure HIV prevention counseling can reduce HIV transmission risks.     

The instrumental overshadowing effect in pigeons: The role of response bursts

Experiment 1 showed that, when reinforcement is delayed by 0.5 sec for pigeons responding on a variable interval schedule, bursts of responses tend to occur during the delay interval. Such bursts are not seen when a signal (illumination of the houselight) fills the delay interval. The higher overall response rate seen with the unsignalled procedure may, therefore, be a consequence of the differential reinforcement of response bursts. Experiment 2 found, however, that the difference between the signalled and unsignalled conditions remained when the signal used was one that was relatively ineffective in suppressing bursts. Experiment 3 found that in some conditions the unsignalled procedure will generate a higher response rate than the signalled procedure even when there is no delay of reinforcement and thus little opportunity for differential reinforcement of response bursts. It is argued that, in addition to any contribution from the differential reinforcement of bursts, these effects also reflect the overshadowing of a response—reinforcer association by the signal that is a more valid predictor of the reinforcer.     

The Transformational Efficacy of Postgraduate Courses

Abstract

Considerable literature exists pertaining to transformative education and academics seek to provide a transformative educational experience for students. The purpose of this research was to examine the perceptions of graduates from postgraduate teacher education courses concerning transformative efficacy with regard to the stated outcomes of the courses. The participants were Christian teachers and school principals from Christian schools across Australia who had graduated from accredited Master of Education or Master of Education (Leadership) courses. Data collection was by way of an online survey containing Likert scales and explanatory statements. The research found that most of the graduates identified transformation at a personal level, particularly in the theological and philosophical understandings that underpin classroom or school leadership practice in Christian schools. This enabled them to be able to critique the cultural artifacts with which educators must deal in their practice.