Knowledge level learning and the power law: A soar model of skill acquisition in scheduling

Zusammenfassung. Das hier vorgestellte Modell lernt graduell, Planungsaufgaben aus der Klasse der Maschinenbelegungsprobleme (job-shop-scheduling problems) zu lösen. Mit Hilfe des Chunking-Mechanismus von Soar wird episodisches Wissen über die Belegungsreihenfolge von Aufträgen auf Maschinen memoriert. Bei der Entwicklung des Modells wurden zahlreiche qualitative (z. B. Transfereffekte) und quantitative Befunde (z. B. Bearbeitungszeiten) aus einer früheren empirischen Untersuchung berücksichtigt. In einer Validierungsstudie wurden dieselben Aufgaben von 14 Probanden und dem Modell bearbeitet. Die Passung von Simulationsdaten und empirischen Ergebnissen fiel insgesamt gut aus. Allerdings löst das Modell die Aufgaben schneller und zeigt auch einen etwas besseren Lernverlauf als die Probanden. Das Modell liefert eine Erklärung für das Rauschen, das typischerweise bei Bearbeitungszeiten zu beobachten ist: es handelt sich um erworbenes Wissen, das mehr oder weniger gut und auch unterschiedlich häufig auf neue Situationen übertragen wird. Der Lernverlauf der Probanden entspricht nur für aggregierte Daten einer Potenzfunktion (power law). Der vorgestellte Mechanismus zeigt, wie ein symbolisches Modell der Informationsverarbeitung graduelle Verhaltensänderungen generiert und wie der offensichtliche Erwerb allgemeiner Prozeduren ohne explizites Lernen von deklarativen Regeln erfolgen kann. Es wird nahegelegt, daß es sich hier um die Modellierung einer Form impliziten Lernens handelt. Summary. The model presented here gradually learns how to perform a job-shop scheduling task. It uses Soar's chunking mechanism to acquire episodic memories about the order to schedule jobs. The model was based on many qualitative (e.g., transfer effects) and quantitative (e.g., solution time) regularities found in previously collected data. The model was tested with new data where scheduling tasks were given to the model and to 14 subjects. The model generally fit these data with the restrictions that the model performs the task (in simulated time) faster than the subjects, and its performance improves somewhat more quickly than the subjects' performance. The model provides an explanation of the noise typically found in problem solving times - it is the result of learning actual pieces of knowledge that transfer more or less to new situations but rarely by an average amount. Only when the data are averaged (i.e., over subjects) does the smooth power law appear. This mechanism demonstrates how symbolic models can exhibit a gradual change in behavior and how the apparent acquisition of general procedures can be performed without resorting to explicit declarative rule generation. We suggest that this may represent a type of implicit learning.     

The puzzle of language evolution

Linguistics must again concentrate on the evolutionary nature of language, so that language models are more realistic with respect to human natural languages and have a greater explanatory force. Multi-agent systems are proposed as a possible route to develop such evolutionary models and an example is given of a concrete experiment in the origins and evolution of word-meaning based on a multi-agent approach.     

Cognitive Sciences Research: More Than Thinking About Drug Abuse

On May 23, 1997, the National Institute on Drug Abuse and the American Psychological Society co-sponsored a conference titled "Cognitive Sciences Research: More Than Thinking About Drug Abuse." The conference highlighted important lines of research, both within and outside of drug abuse, that may elucidate the relationships between substance abuse and cognitive processes. This Special Section of Psychological Science presents a compilation of articles from that conference by scientists who are working in the forefront of this exciting new research area. The research questions posed by these articles take the following forms: What are the cognitive and developmental effects (i.e., the consequences) of substance abuse? What are the antecedents or precursors of drug use that render persons vulnerable to taking drugs? How do the effects of drugs, in turn, become antecedents for changes in perception, behavior, and cognition that further enhance vulnerability to drugs?     

Book reviews

Christianity. Brian Wilson, 1999. Religions of the World. London, Routledge. 128 pp., pb. £6.99, ISBN 0 415 21161; hb. £25.00, ISBN 0 415 21342 8

Islam. Jamal J. Elias, 1999. Religions of the World. London, Routledge. 128pp., pb. £6.99, ISBN 0 415 21165 4; hb. £25.00, ISBN 0 415 21344 4

Islam. Jan Slomp, 1999. Kampen, Uitgeverij Kok. 142 pp., pb.NLf 19,90, ISBN 90 242 9372 3

Windows on the House of Islam: Muslim sources on spirituality and religious life. John Renard (Ed.), 1998. Berkeley, Los Angeles, London, University of California Press. xx + 431pp., pb. £15.95, ISBN 0 520 21086 7

Shattering the Myth: Islam beyond violence. Bruce B. Lawrence, 1998. Princeton, Princeton University Press. xix + 237 pp., hb. $17.95, ISBN 0 691 05769 9

Islam and Other Faiths. Ismail Raji al‐Faruqi, ed. Ataullah Siddiqui, 1998. Leicester, the Islamic Foundation and The International Institute of Islamic Thought. 370 pp., pb. n.p., ISBN 0 86037 276 6

Christian‐Muslim Dialogue: theological and practical issues. Roland E. Miller & Hance A.O. Mwakabana (Eds), 1998. LWF Studies 3/1998. Geneva, Department for Theology & Studies—The Lutheran World Federation. 391pp., pb., n.p., ISBN 3 906706 63 X

Islam and the West: conflict, co‐existence or conversion?. Colin Chapman, 1998. Carlisle, Paternoster. 198 pp. pb. £12.99, ISBN 0 85364 781 X

The Rights of Women in Islam: an authentic approach. HaifaaJawad, 1998. London, Macmillan Press. 150pp., pb, £15.99, ISBN 0 333 73458 0; hb. £42.50, ISBN 0 333 65086 7

Greek Thought, Arabic Culture: the Graeco‐Arabic translation movement in Baghdad and early Abbasid society (2nd‐4th/8th‐10th centuries). D. Gutas, 1998. London, Routledge. 256pp., hb. £45.00, ISBN 0 415 06123 6; pb. £14.99, ISBN 0 415 061334

Ibn ‘Arabi in the Later Islamic Tradition: the making of a polemical image in medieval Islam. Alexander D. Knysh, 1999. Albany, NY, State University of New York Press. xvi + 449 pp., pb. $27.95, ISBN 0 7914 3968 2; hb. $81.50, ISBN 0 7914 3967 4

Love, Religion and Politics in Fifteenth‐century Spain. Ian Macpherson & Angus MacKay, 1998. Medieval Iberian Peninsula Texts and Studies 13. Leiden, Boston & Cologne, Brill. 286 pp., hb. Nig. 165.00/US$ 97.25, ISBN 90 04 10810 6

Shi'i Scholars of Nineteenth‐century Iraq: the Ulama of Najaf and Kerbala. MeirLitvak, 1998. Cambridge Middle East Studies. Cambridge, Cambridge University Press. 264pp., hb. £35.00, ISBN 0521623561

Islam and Postcolonial Narrative. John Erickson, 1998. Cambridge, University Press. 243 pp., hb. £35.00, ISBN 0 521 59423 5

Imperialism and Orientalism. Barbara Harlow & Mia Carter (Eds), 1998. Oxford, Blackwell. 416 pp., hb. £65.00, ISBN 1 55786 710 0; pb. £16.99, ISBN 1 55786 711 9

Islam et Occident face a face: regards de I'histoire des religions. Jacques Waardenburg, 1998. Geneva, Labor et Fides. 144 pp., pb. n.p., ISBN 2 8309 0786 8

Against Islamic Extremism: the writings of Muhammad Sa'Id al‐'Ashmawy. Carolyn Fluehr‐Lobban (Ed.), 1998. Florida, University Press of Florida. 131 pp., hb. £39.95, ISBN 0 8130 1546 4

Spokesmen for the Despised: fundamentalist leaders of the Middle East. R. Scott Appleby (Ed.), 1997. Chicago, Chicago University Press. 438 pp., pb. £15.95, ISBN 0 226 02125 4; hb. n.p., ISBN 0 226 02124 6. Muslim European Youth: reproducing ethnicity, religion, culture. Steven Vertovec & Alisdair Rogers (Eds), 1998. Aldershot, Ashgate

215 pp., hb. £35.00, ISBN 1 84014 341 X

Islam in Germany and France. Muslime in Deutschland: Nebeneinander oder Miteinander. Ursula Spuler‐Stegemann, 1998 Freiburg, Herder. 352 pp; hb. DM 24,80, ISBN 3 451 04419 6

Musulmans de France: diversite, mutations et perspectives de l'islam francais,. Gilles Couvreur, 1998. Paris, Les editions de Fatelier. 112pp., pb. FF 65, ISBN 2 7082 3384 X

Ionian Vision: Greece in Asia Minor 1919–1922. Michael Llewellyn Smith, 1998. London, Hurst. xxi + 401 pp., hb. £40.00, ISBN 185065 413 1; pb. £14.95, ISBN 1 85065 368 2

The History of Saudi Arabia. Alexei Vassiuev, 1998. London, Saqi Books. 576 pp., hb. £45.00, ISBN 0863569358

City of Stone: the hidden history of Jerusalem. Meron Benvenisti, 1998. Berkeley, University of California Press. viii + 274 pp., pb. $16.95/£10.95, ISBN 0 520 20768 8

The Politics of Muslim Cultural Reform: Jadidism in Central Asia. Adeeb Khalid, 1998. Berkeley, University of California Press. xxiii + 335 pp., hb. $55.00, ISBN 0 520 21355 6; pb. $22.00, ISBN 0 520 21356 4

Ethnicity, Law and Human Rights: the English experience. Sebastian Poulter, 1998. Oxford, Clarendon Press. xxxvii +418pp., hb. £45.00, ISBN 0 19 825773 2

Muslim Family Law. David Pearl & Werner Menski, 1998. 3rd edn. London, Sweet & Maxwell. xii + 551pp., pb. £55.00, ISBN 0421 52980 6

Religion in Prison: equal rites in a multi‐faith society. James A. Beckford & Sophie Gilliat. Cambridge, Cambridge University Press. xiv + 232 pp., hb. £35.00, ISBN 0 521 62246 8

Educating Muslim Girls: shifting discourses. Kaye Haw, 1998. Buckingham/Philadelphia, Open University Press. xii +203pp., pb. £15.99, ISBN 0 335 19773 6; hb. £50.00, ISBN 0 335 19774 4     

Changing explanatory frameworks in the U.S. government’s attempt to define research misconduct

Nearly two decades of debate have not settled the definition of research misconduct. The literature provides four explanatory frameworks for misconduct. The paper examines these frameworks and maps them onto efforts by the U.S. Public Health Service to define research misconduct and subsequent responses to these efforts by the scientific community. The changing frameworks suggest that closure will not be achieved without an authoritative effort, which may occur through the Research Integrity Panel’s recent attempt to create a government-wide definition.     

Economic practices of Jesus movement groups

This paper examines in detail the multitude of ways used by Jesus Movement organizations to raise money to fund their many activities. The research was provoked by sharp differences between fund‐raising methods used by the two largest and well known JM organizations—the Children of God (now called The Family) and Christ Communal Organization (a pseudonym for a group called Shiloh). The COG mainly relied on various forms of public solicitation, while Shiloh depended on working for others and themselves in an effort to become self‐supporting. Seven other JM groups were examined to find out what patterns of support were most prevalent, and to examine possible relationships between sustenance activities and theological developments within the groups. A large number of experimental approaches were taken by JM groups trying to sustain themselves during their sometimes tumultuous histories, leading to a number of general conclusions.