Assessing potential reinforcement-like effects of brief stimuli unrelated to food reinforcers

It is widely assumed that reinforcers are biologically relevant stimuli, or stimuli that have been associated with biologically relevant stimuli. However, brief, arbitrary stimuli have also been reported to have reinforcement-like effects, despite being unrelated to biologically relevant stimuli like food. The present study explored the potential reinforcement-like effects of brief stimuli across 5 experiments. In Experiments 1 through 4, pigeon subjects responded for food reinforcement and brief stimulus presentations in a 2-component multiple schedule. Neither baseline response rates nor resistance to change during disruption tests were systematically greater in a component with versus without brief stimulus presentations. Increasing the rate and duration of brief stimulus presentations in Experiment 4 did not reveal reinforcement-like effects when compared directly with food. In Experiment 5, pigeons chose between independent terminal links in a concurrent-chains procedure. Across conditions, varying the location, duration, and rate of brief stimulus presentations in the terminal links had no systematic effects on preference. In contrast, varying rates of food reinforcers resulted in large and reliable shifts in preference. Therefore, the present study found no systematic evidence that brief stimuli unrelated to food reliably increase response rates, resistance to change, or preference. These data demonstrate the value of systematic replication, and a behavioral momentum approach to assessing potential reinforcement-like effects.     

Book reviews

Arnold, M. Memory and the brain. Hillsdale, N. J.: Lawrence Erlbaum Associates. 1984. Pp. 532. ISBN 0-89859-290-9. £47.90.

Green, T. R. G., Payne, S. P. and van der Veer, G. C. (Eds.). The psychology of computer use.. London: Academic Press. 1983. Pp. 225. ISBN 0-12-2974204. $9.50.

Stunkard, A. J. and Stellar, E. (Eds.). Eating and its disorders. New York: Raven Press. 1984. Pp. 302. ISBN 0-89004-891-6. $58.50.

Spillmann, L. and Wooten, B. R. (Eds.) Sensory experience, adaptation, and perception: Festschrift for Zero Kohler. Hillsdale, N. J.: Lawrence Erlbaum Associates. 1984. Pp. xxvii + 748. ISBN 0 8985-3-218-6. £70.85.

Geschwind, N. and Galaburda, A. M. (Eds.)Cerebral dominance: The biological foundations. Cambridge, Mass.: Harvard University Press. 1984. Pp. 232. ISBN 0-674-10658-X. £24.35.

Annett, M. Left, right, hand and brain: The right shift theory. 1985. London and Hillsdale, N. J.: Lawrence Erlbaum Associates. Pp. xiii + 474. ISBN 0-86377418-5 £29.95.

Ericsson, K. A. and Simon, H. A. Protocol analysis: Verbal reports as data. Cambridge, Mass.: The M.I.T. Press. 1984. Pp. 426. ISBN 0-262-05029-3. £28.95.     

Audience Design in Multiparty Conversation

How do speakers design what they say in order to communicate effectively with groups of addressees who vary in their background knowledge of the topic at hand? Prior findings indicate that when a speaker addresses a pair of listeners with discrepant knowledge, that speakers Aim Low, designing their utterances for the least knowledgeable of the two addressees. Here, we test the hypothesis that speakers will depart from an Aim Low approach in order to efficiently communicate with larger groups of interacting partners. Further, we ask whether the cognitive demands of tracking multiple conversational partners' perspectives places limitations on successful audience design. We find that speakers can successfully track information about what up to four of their partners do and do not know in conversation. When addressing groups of 3–4 addressees at once, speakers design language based on the combined knowledge of the group. These findings point to an audience design process that simultaneously represents the perspectives of multiple other individuals and combines these representations in order to design utterances that strike a balance between the different needs of the individuals within the group.     

RELIABILITY AND FACTORIAL VALIDITY OF THE JUNIOR EYSENCK PERSONALITY QUESTIONNAIRE IN ZIMBABWE

Six-hundred and thirteen girls and 601 boys in Zimbabwe completed the Junior Eysenck Personality Questionnaire (JEPQ). The reliability of the Neuroticism (N) and Social Desirability (L) factors was acceptable but the Psychoticism (P) and Extraversion (E) factors possessed modest reliability. While the factorial validity of the P, N and L scales was acceptable, the factorial validity of the E scale was poor. L scores were significantly correlated with N and P scores among girls and boys. Whereas Zimbabwean girls reported higher P scores than did Canadian girls, Zimbabwean boys reported lower P scores than did Canadian boys. Zimbabwean girls and boys reported lower E and N and higher P scores than their Canadian counterparts. This study provides broad support for Eysenck's basic personality model, but it does not support the use of this version of the JEPQ, and especially the E scale, among Zimbabwean children.     

Bias in the use of base rates: Racial prejudice in decision-making

Two studies investigated biases in the use of base rate information when assessing the probability of a witness' accurate identification of a white or West Indian as a burglar. An adapted version of the Kahneman-Tversky cab problem was used, to provide a social decision in which biases could be measured against some normative standard. Ethnicity of youth (white/West Indian) and nature of base rate (incidental/causal) were manipulated in a 2 × 2 between-subjects design. A significant interaction effect revealed that subjects took no account of the base rate for a West Indian subject, but used the base rate only when it was causal and the youth was white. This ‘prejudice effect’ against a West Indian youth and ‘exoneration effect’ for a white youth were replicated in a second study, using a microcomputer and chronometric analyses. Results are discussed in terms of heuristic decision-making, social schemata, and the cognitive versus motivational bases of bias in the use of base rates.