Human nonverbal counting estimated by response production and verbal report

In three experiments, people were shown sequential displays and were prevented from verbal counting by being required to perform other cognitive tasks. In Experiment 1, the subjects were shown three 1.target (target5 = 8, 16, or 32) sequences of colored geometric shapes. On occasional question trials, the subjects were asked to estimate the target number after the final item in the sequence. On other test trials, items continued to appear beyond the target, and the subjects estimated the target manually by tapping a space bar. In Experiments 2 and 3, a matching-to-sample procedure required the subjects to estimate the same sequence of items (target = 8, 11, 14, 17, or 20) both verbally and manually. The results indicated that (1) manual and verbal estimates closely approximated target size in Experiments 1 and 2, (2) coefficients of variation were constant across target size, and (3) correlations between manual and verbal estimates were positive in Experiments 2 and 3. Requiring the subjects to perform a counting task during presentation of items led to underestimation of number in Experiment 3. nt]mis|This research was funded by a research grant from the Natural Sciences and Engineering Research Council of Canada to W.A.R. and by the Ontario Graduate Scholarship in Science and Technology and the Ontario Graduate Scholarship to M.J.B.     

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.     

The relationship between aggression in children and locus of control beliefs

Gender differences are evident in the etiology and maintenance of aggressive behavior (which is on the increase for both male and female youths), but the explanatory models that have been proposed, including social learning theory and information processing models, are more appropriate for boys than for girls. In an attempt to elucidate processes underlying aggression, particularly for girls, the authors explored locus of control as a cognitive variable possibly related to aggressive behavior. The relationships between teacher-reported aggression and 3 types of locus of control (internal, powerful other, and unknown) for success and failure experiences were investigated. For girls, aggressive behavior was positively related to internal and unknown locus of control. In contrast, boys' aggressive behavior was unrelated to internal locus of control beliefs and negatively related to external locus of control beliefs. Possible explanatory mechanisms for the relationship between locus of control beliefs and aggression are discussed. The present study contributes to the understanding of aggression in girls and points to different processes underlying girls' and boys' aggression.     

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.     

Conjoint dissociations reveal involuntary "perceptual" priming from generating at study.

Incidental perceptual memory tests reveal priming when words are generated orally from a semantic cue at study, and this priming could reflect contamination by voluntary retrieval. We tested this hypothesis using a generate condition and two read conditions that differed in depth of processing (read-phonemic vs read-semantic). An intentional word-stem completion test showed an advantage for the read-semantic over the generate condition and an advantage for the generate over the read-phonemic condition, and completion times were longer than in a control test, prior to which there was no study phase. An incidental word-stem completion test showed equivalent priming for the read-semantic and read-phonemic study conditions, despite considerable power, and completion times were no longer than control, indicating that retrieval was involuntary, and insensitive to prior conceptual processing. The generate condition produced less priming than the read conditions, but significant priming nonetheless. The results show that priming from generating can be involuntary and suggest that lexical processes are responsible. They are also the first results conjointly showing a crossed double dissociation, a single dissociation, and a parallel effect across memory tests with identical physical retrieval cues.     

A delivery system for olfactory stimuli

This paper describes the design of a new method for controlling and administering olfactory stimuli—namely, thehood system. The hood system involves a stream of vaporized odor (at known concentrations) mixed with odorless air and pumped (at a constant flow rate) into an oxygen therapy hood. It is designed to be used with odorants in solution, such as essential oils, as the olfactory stimulus. The use of oxygen therapy hoods allows for the precise control of a constant concentration of odorized air over time, while allowing subjects to breathe normally. The hood system provides a natural administration of olfactory stimuli and the exact determination of the stimulus concentration. The use of this system will allow experimental conditions to be completely defined and results and replication studies to be accurately interpreted. The hood system is portable, cost effective, and constructed from readily available components. It is proposed that the hood system could be adopted to suit a wide range of olfactory research, particularly that in which the effects of chronic exposure to olfactory stimuli on cognition are examined.