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.     

Intended and unintended effects of explicit warnings on eyewitness suggestibility: Evidence from source identification tests

Previous studies have shown that source identification (ID) tests reduce, and in some cases eliminate, eyewitness suggestibility errors. The present study showed that the suggestibility errors participants committed on a source ID test were further reduced when they were given the explicit postwarning that the experimenter was trying to trick them. These postwarnings reduced suggestibility to the same extent as prewarnings, and they did so for both once and repeatedly suggested items. In addition, the benefits of the pre- and postwarnings persisted when participants were retested 1 week later, but only if the suggestions had been repeated. For once-suggested items, the warning had the unintended effect of improving old/new recognition of the suggested information at retest, an effect that offset the improvements in source discrimination accuracy conferred by the warning. The advantages of using source ID tests for investigating group differences in eyewitness suggestibility are discussed.     

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 the Media Create Public Opinion? A Social-Identity Approach

The media remains a powerful presence in U.S. culture. It gives people news of world and local events, it entertains, and it may even function as a companion to children. Because it functions as a window to the outside world, what appears across its landscape actually may become people's reality. Thus, the potential for distorting their view of that world is high if the picture provided is unrepresentative of actual events. For example, the prevalence of violent acts on television has been linked to increased aggression and escalating impressions of a dangerous world, and the overrepresentation of youth and beauty may be a causal factor of eating disorders. In this article, we explore the possibility that the media may also serve as a powerful creator of the very public opinions it seeks to reflect in its news. Subtle nonverbal cues of newscasters have been shown to influence voting behavior, and the media's overrepresentation of the proportion of blacks in poverty may decrease whites' support of welfare. By portraying a world in which people's opinions are based on their ethnic or demographic group membership, the media may also subtly but powerfully create the very opinions they seek to reflect.     

Video game violence: A review of the empirical literature

The popularity of video games, especially violent video games, has reached phenomenal proportions. The theoretical line of reasoning that hypothesizes a causal relationship between violent video-game play and aggression draws on the very large literature on media violence effects. Additionally, there are theoretical reasons to believe that video game effects should be stronger than movie or television violence effects. This paper outlines what is known about the relationship between violent video-game playing and aggression. The available literature on virtual reality effects on aggression is discussed as well. The preponderance of the evidence from the existing literature suggests that exposure to video-game violence increases aggressive behavior and other aggression-related phenomena. However, the paucity of empirical data, coupled with a variety of methodological problems and inconsistencies in these data, clearly demonstrate the need for additional research.     

Assessment and Diagnosis of DSM-IV Anxiety Disorders

Anxiety disorders, the 2nd most common type of mental disorders, are among the most frequently missed or misdiagnosed disorders (Frances & Ross, 1996). Once they are diagnosed, effective treatments exist for them. This article provides a review of current knowledge on the assessment and diagnosis of anxiety disorders classified in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (American Psychiatric Association, 1994). Emphasis is on the recognition of anxiety as a dominant symptom, frameworks for determining specific anxiety disorders, and patterns of comorbidity.