Low alpha power (7.5–9.5 Hz) changes during positive and negative affective learning

There is evidence that the positive and the negative word lists of the Affective Auditory Verbal Learning Test (AAVL) are useful with regard to mood induction. To date, however, changes in brain activation, as indicated by quantitative electroencephalographic recording, have not been examined. Thus, changes in low alpha power (7.5-9.5 Hz) were examined during and after completion of the positive or the negative learning list of the AAVL among 37 undergraduate men and women. Three primary findings from the study include the following: (1) Previously reported recall patterns were replicated; (2) participants who completed the negative list reported a significant decline in mood state at the end of the session; and (3) participants who completed the negative word list evidenced a significant reduction in low alpha power (in comparison with baseline) within the parietal regions. The findings noted above are seemingly counter to contemporary theories of mood regulation (i.e., asymmetrical changes in anterior activity, rather than changes in parietal regions). Although the AAVL may have limited utility as a tool for mood induction, it may serve as a functional tool for examination of the cerebral processes associated with affective verbal memory.     

Strategic aspects of numerosity judgment: the effect of task characteristics

In previous investigations we documented that people use several strategies to determine different numerosities of blocks that are presented in a square grid. One of these strategies is the clever subtraction strategy, wherein the number of empty squares in the grid is subtracted from the total number of squares in the grid. In the present study we investigated participants' flexibility in strategy use when varying the shape of the grid. Analysis of the results in terms of the theoretical framework of Lemaire and Siegler (1995) regarding strategic change shows that this contextual variable affected the frequency, execution time, and accuracy of subjects' use of the subtraction strategy. The usefulness of this framework for analyzing the nature of the adaptation to contextual variations is discussed. From a methodological point of view, this study documents the potential of Beem's (1993, 1999) segmented linear regression models for assessing subjects' strategy use in cognitive tasks.     

Visual perspective taking for avatars in a Simon task

In modern digital applications, users often interact with virtual representations of themselves or others, called avatars. We examined how these avatars and their perspectives influence stimulus–response compatibility in a Simon task. Participants responded to light/dark blue stimuli with left/right key presses in the presence of a task-irrelevant avatar. Changes in stimulus–response compatibility were used to quantify changes in the mental representation of the task and perspective taking toward this avatar. Experiments 1 and 2 showed that perspective taking for an avatar occurred in orthogonal stimulus–response mappings, causing a compatibility effect from the avatar’s point of view. In the following two experiments we introduced a larger variety of angular disparities between the participant and avatar. In Experiment 3, the Simon effect with lateralized stimulus positions remained largely unaffected by the avatar, pointing toward an absence of perspective taking. In Experiment 4, after avatar hand movements were added in order to strengthen the participants’ sense of agency over the avatar, a spatial compatibility effect from the avatar’s perspective was observed again, and hints of the selective use of perspective taking on a trial-by-trial basis were found. Overall, the results indicate that users can incorporate the perspective of an avatar into their mental representation of a situation, even when this perspective is unnecessary to complete a task, but that certain contextual requirements have to be met.     

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.