Utility of Behavior Ratings by Examiners During Assessments of Preschool Children With Attention-Deficit/Hyperactivity Disorder

This study examines the clinical utility of behavior ratings made by nonclinician examiners during assessments of preschool children with Attention-Deficit/Hyperactivity Disorder (AD/HD). Matched samples of children with (n = 127) and without (n = 125) AD/HD were utilized to test the internal, convergent, concurrent, and incremental validity of ratings completed by examiners on the Hillside Behavior Rating Scale (HBRS). Results indicated that HBRS ratings were internally consistent, possessed sufficient interrater reliability, and were significantly associated with parent and teacher reports of AD/HD when controlling for age, gender, intelligence, and symptoms of other psychopathology. HBRS ratings also were significantly associated with other measures of functioning, and provided a significant increment in the prediction of impairment over parent and teacher report alone. These findings suggest that behavioral ratings during testing provide a unique source of clinical information that may be useful as a supplement to parent and teacher reports.     

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.     

Can Bartlett’s repeated reproduction experiments be replicated?

Surprisingly, Bartlett's (1932) famous repeated reproduction experiments, in which he found systematically increasing errors in recall from the same people tested over time, have never been successfully replicated. Several studies have attempted partial replications, which were unsuccessful, and their authors concluded that the original observations might not be replicable. We conducted a study modeled closely after Bartlett's procedures: Subjects studied "The War of the Ghosts," took an initial test 15 min later, and then took a delayed test after 1 week. A follow-up test was conducted 6 months later on as many subjects as could be obtained. We did replicate Bartlett's results, in that (1) subjects forgot the story over delays but (2) introduced rationalization and distortion into their accounts of the story, with increases in the proportion of material distorted as retention interval increased. Subjects also imported new propositions at long delays, further confirming Bartlett's empirical observations and conclusions. Bartlett's repeated reproduction results can be replicated.