The control of choice by its consequences

Five pigeons were trained on concurrent variable-interval schedules in which equal rates of reinforcement were always arranged for left- and right-key responses, but different overall rates were signaled by key colors. Sessions began with both keys lit yellow for the instrumental phase. If, after 20 s of this phase, the relative number of responses that had been made to the left key equaled or exceeded .75, both keys changed red for the contingent phase. The contingent phase arranged another concurrent variable-interval schedule for a further 20 s before the instrumental phase was reinstated. However, if preference in the instrumental phase did not exceed .75, the instrumental phase continued for a further 20 s before preference was again compared with the criterion. In Part 1, the reinforcer rate arranged in the instrumental phase was held constant at 4.8 reinforcers per minute, while the reinforcer rate arranged in the contingent phase was varied across conditions from 0 to 19.2 over five steps. In Part 2, reinforcer rates in the contingent phase were kept constant at 36 per minute, while reinforcer rates in the instrumental phase were varied from 0 to 36 over seven steps. Part 3 replicated Part 2 but used reinforcer rates in both phases that were one third of those arranged in Part 2. Measures of choice obtained by summing responses across presentations of the instrumental phase became more extreme toward the left key as the reinforcer rate obtained in the contingent phase was increased (Part 1) and as the reinforcer rate obtained in the instrumental phase was decreased (Parts 2 and 3). Changes in these measures of choice were accompanied by systematic changes in the relative frequency with which the criterion was exceeded. Changes in both these measures were correlated with changes in the relative frequency with which subjects responded exclusively to the left key. These results are discussed with respect to the two choices that were concurrently available in this procedure and the response alternatives that might constitute the concurrent operants in each choice.     

Book reviews

God, Reason, and Religions: new essays in the philosophy of religion. Eugene Thomas Long (Ed.), 1995. Dordrecht Kluwer Academic. 228 pp., hb. £67.50, ISBN 07 923333 810 3

Christians and Muslims: from double standards to mutual understanding. Hugh Goddard, 1995. London, Curzon Press. 200 pp., pb. £14.99, ISBN 0 7007 0364 0

Al‐Bayanat al‐Masihiyya al‐Islamiyya al‐Mushtaraka. Juliette Haddad (Ed.), 1995. Beirut, Dar al‐Mashriq. 207 pp., pb. n.p., ISBN 2 7214 5005 0

Muslim Writers on Judaism and the Hebrew Bible, from Ibn Rabban to Ibn Hazm. Camilla Adang, 1996. Leiden, E. J. Brill. 321 pp., hb. NLG140, ISBN 90 04 10034 2

Abū Ya qūb al‐Sijistani: intellectual missionary. Paul E. Walker, 1996. London, I. B. Tauris. 132 pp., rib. £35, ISBN 1 85043 921 4

The Cambridge Survey of World Migration. Robin Cohen (Ed.), 1995. Cambridge, Cambridge University Press. 570 pp., hb. n.p. ISBN 0 521 44405 5

Musulmans en Europe occidentals bibliographic commentée. Muslims in Western Europe: an annotated bibliography. Felice Dassetto & Yves Conrad (Eds), 1996. Paris, Editions L'Harmattan. 202 pp., pb., n.p., ISBN 2 7384 4126 2

Muslim Politics. Dale F. Eickelman & James Piscatori, 1996. Princeton, NJ, Princeton University Press. 235 pp., pb. n.p., ISBN 0 691 00870 1

Islam and the Myth of Confrontation: religion and politics in the Middle East. Fred Halliday, 1996. London, I. B. Tauris. 255 pp., £12.95, ISBN 1 85043 959 1

Nine Parts of Desire: the hidden world of Islamic women. Geraldine Brooks, 1995. New York, Doubleday. 255 pp. hb. £22.95, ISBN 0 385 47576 4

Aunt Safiyya and the Monastery. Bahaa’ Taher, 1996. Translated from the Arabic by Barbara Romaine. Berkeley, University of California Press. 124 pp., pb. n.p., ISBN 0 520 20075 6

Dreams of Trespass: tales of a harem girlhood. Fatima Mernissi, 1994. Reading, MA, Addison‐Wesley. 242 pp. pb., ISBN 0 201 62649 7

Lettres et message d'Algérie. P. Claverie, 1996. Paris, Karthala. 222 pp., pb. 120FF, ISBN 2 86537 657 5

Islamic Resurgence and Islamization in Malaysia. S. Batumalai, 1996. Perak, Malaysia. 279 pp., pb. RM 25/‐, no ISBN

Christian‐Muslim Relations: a case study of Sarawak, East Malaysia. Theodore Gabriel, 1996. Aldershot, Avebury. xiv, 133 pp., n.p., ISBN 1 85972 325 X

Muslim Communities in the New Europe. Gerd Nonneman, T. Niblock & B. Sjajkowski (Eds), 1996. Reading, Ithaca Press. 356 pp., hb. £35.00, ISBN 0 86372 192 3

Al‐Mughtaribun: American law and the transformation of Muslim life in the United States. Kathleen M. Moore, 1995. Albany, State University of New York Press. 211 pp., pb. $16.95, ISBN 0 7914 2580 0

The Landscape of Belief: encountering the Holy Land in nineteenth‐century American art and culture. [The Princeton Series in Nineteenth‐Century Art, Culture, and Society]. John Davis, 1996. Princeton, Princeton University Press. 264 pp., hb. $65.00, ISBN 0 691 04373 6     

Organizational reward systems: Implications for climate

This study investigated the role of systematically different organizational reward structures upon individual perceptions of the reward climate. Nurses in a naval hospital worked for the same supervisors but were subject to either tenure-contingent (N=73) or behavior-contingent (N=50) reward systems. No differences in perceived reward climate were found between the two groups. In the tenure-contingent group, job attitudes reflected individual characteristics rather than perceived climate. The opposite relationship was found for the behavior-contingent group.Support for this research was provided under Office of Naval Research Contract RR942-08-01 NR 170-915. Opinions expressed are those of the author. No endorsement by the Department of the Navy has been given, nor should it be inferred. Portions of the study were conducted while the author was at the Naval Health Research Center in San Diego. The author would like to thank R. J. Bullock, Mark C. Butler, L. R. James, and R. D. Pritchard for their helpful comments and assistance.     

Some effects of rhythmic context on melody recognition

The effects of rhythmic context on the ability of listeners to recognize slightly altered versions of 10-tone melodies were examined in three experiments. Listeners judged the melodic equivalence of two auditory patterns when their rhythms were either the same or different. Rhythmic variations produced large effects on a bias measure, indicating that listeners judged melodies to be alike if their rhythms were identical. However, neither rhythm nor pattern rate affected discriminability measures in the first study, in which rhythm was treated as a within subjects variable. The other two studies examined rhythmic context as a between subjects variable. In these, significant effects of temporal uncertainty due to the number and type of rhythms involved in a block of trials, as well as their assignment to standard and comparison melodies on a given trial, were apparent on both discriminability and bias measures. Results were interpreted in terms of the effect of temporal context on the rhythmic targeting of attention.     

Probability Distortions and Outcome Desirability: Experimental Verification of Medical Folklore1

A belief common among medical personnel is that in conveying diagnoses or prognoses to patients, it is always best to emphasize the positive. In order to see if emphasis on the positive does make a difference in one's expectation of the more desirable of two alternative outcomes actually occurring, this laboratory experiment was conducted. College students were led to believe they had a low, moderate, or high probability of being assigned to one of two tasks, which differed in desirability. For some students the instructions focused on the probability of being assigned to the desirable task, whereas for others the instructions focused on the probability of being assigned to the undesirable. The two probabilities were always complementary; that is, the probability of being assigned to the desirable task was equal to one minus the probability of being assigned to the undesirable task. Following an interpolated activity, each subject's expectation of being assigned to the desirable or undesirable task was measured. Across all probability levels, subjects for whom the instructions had focused on the probability of being assigned to the desirable task viewed that assignment as significantly more likely than did subjects for whom the instructions had focused on the complementary probability of being assigned to the undesirable task. The implications of this for communicating with patients, for preventive medicine, and for coping with serious illness are briefly discussed.     

Exploring self-forgiveness

This article presents the results of a phenomenological study of the experience of self-forgiveness. On the basis of in-depth interviews with seven subjects, self-forgiveness is described not as an achievement but rather as a gift where one moves from estrangement and brokenness to a sense of at-homeness.This article is based in part on a paper presented at the Eighth International Human Science Research Conference at the University of Aarhus, Denmark, in August 1989. The authors thank their colleagues Carolyn Grissom and Jodi Kelly for their helpful suggestions.     

Intensity and direction as dimensions of competitive state anxiety and relationships with competitiveness.

This study examined differences in intensity and direction of symptoms of competitive state anxiety in high and low competitive subjects from the sports of rugby union, basketball, soccer, and field hockey. The 69 men were dichotomized via a median-split into high and low competitive groups based on their scores on the Sport Orientation Questionnaire. All subjects completed a modified version of the Competitive State Anxiety Inventory-2 30 minutes prior to competition. This inventory included the original intensity scale plus a direction scale on which subjects rated the extent the experienced intensity of each symptom was either facilitative or debilitative to subsequent performance. There were no significant group differences on intensity of cognitive anxiety or of somatic anxiety or on direction of somatic anxiety; however, the highly competitive group of 34 subjects reported their anxiety as more facilitative and less debilitative than the low competitive group (n = 35). This supports the proposal that sports performers' directional perceptions of their anxiety symptoms may provide further understanding of the competitive state-anxiety response.     

Sample-stimulus discriminability and sensitivity to reinforcement in delayed matching to sample

Five pigeons were trained in a delayed matching-to-sample task with red and green stimuli. The retention interval between sample-stimulus presentation and the availability of the choice stimuli was varied between 0.01 s and 12 s within each session. The probability of food produced by correct-red and correct-green responses was varied across conditions. Sample-stimulus discriminability and response bias were measured at four different retention intervals. The results of these analyses showed an interaction between the discriminability of the sample stimuli and the control exerted by differential reinforcement. At longer retention intervals, sample discriminability decreased and sensitivity of choice behavior to changes in the red/green reinforcer ratio increased. An analogous relation has been reported in conditional discriminations in which the physical disparity of stimuli has been varied. This correspondence suggests that increasing the delay between presentation of one of two stimuli and an opportunity to respond discriminatively to it may be functionally similar to increasing the physical similarity of the two stimuli.