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.     

From Neo-Kantianism to Logicism: Vvedenskij's Mature Years

In the first two decades of the century Vvedenskij developed and defended what he took to be an original argument in support of the impossibility of metaphysical knowledge. This argument, which he hailed as a proof, involved an examination of the four laws of thought alone. As it made no appeal to the highly technical analyses found in Kant's first Critique, Vvedenskij considered it to be more efficient and thereby effective than Kant's own arguments. Although Vvedenskij's estimation of his accomplishment actually increased with the passage of time, the proof rested on highly dubious assumptions.     

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     

Why Don't People Change? What Stops Them from Changing? An Integrative Commentary on the Special Issue on Resistance

This commentary discusses the four papers from the vantage point of a cognitive-developmental view. Psychotherapeutic change involving changes in core cognitive structures is seen as threatening an individual's personal sense of identity as well as security and safety needs. Core cognitive constructs are laid down early via the principle of covariation of events and form the basis of our tacit knowledge base. Subsequent changes in this tacit knowledge is difficult because the core cognitive constructs act like a mental filter to screen in confirming data and screen out disconfirming data. Ambiguous stimuli tend to be interpreted on the basis of preexisting cognitive constructs, even when the match between event and interpretation is not ideal. Several suggestions are given for increasing the probability of changes occurring in core cognitive constructs.     

The Role of Schools in Outcomes for Youth: Implications for Children's Mental Health Services Research

We explore the role of schools in children's mental health services research. Recent literature has suggested that schools play an important role in delivering services to children and adolescents with emotional and behavioral problems. Research in services research, though, has taken a fairly narrow view of which dimensions of school environments are relevant for inclusion in studies. We suggest that a broader view of school environments is appropriate and potentially beneficial to the field. Using Bronfenbrenner's ecological model as a guide, we conceptualize schools as microsystems. Such an approach suggests that all aspects of school environments (treatment as well as non-treatment) are likely to influence many of the outcomes that children's mental health services research frequently targets (e.g., behavioral problems, problematic peer relationships, academic achievement, school attendance). We review literature from a variety of disciplines to suggest relevant features of schools, with particular attention to the role of peer dynamics within schools. We conclude with implications of this expanded conceptualization of schools for children's mental health services research.     

Body Size Beliefs and Weight Concerns Among Mothers and Their Adolescent Children

African American and White mother/adolescent pairs were examined for familial associations in body size and weight concerns. Mothers' and adolescents' estimates of adolescents' body mass index (BMI) were significantly correlated. Compared to boys, girls had greater body dissatisfaction, higher weight concerns, and perceived higher family/friend weight concerns. By race, White adolescents had more body dissatisfaction and greater concern about weight than African American adolescents. Four items explained 70.4% of the variance in adolescents' weight concern scores: adolescents' weight management practices, mothers' reports of adolescents' saying they were too fat, adolescents' perceptions of family/friends' weight concerns, and adolescents' body dissatisfaction. Our study suggests White girls are more concerned about their weight and perceive greater weight and dieting concerns among family/friends than African American girls.