Perceiving distance: a role of effort and intent

Perceiving egocentric distance is not only a function of the optical variables to which it relates, but also a function of people's current physiological potential to perform intended actions. In a set of experiments, we showed that, as the effort associated with walking increases, perceived distance increases if the perceiver intends to walk the extent, but not if the perceiver intends to throw. Conversely, as the effort associated with throwing increases, perceived distance increases if people intend to throw to the target, but not if they intend to walk. Perceiving distance combines the geometry of the world with our behavior goals and the potential of our body to achieve these goals.     

Index of suspicion: feeling not believing

Throughout the U.S., state laws require professionals who work with children to report cases of suspected child abuse to child protection services. Both practically and conceptually, however, significant problems arise from a lack of clarity regarding the threshold that has been set for reporting. Specifically, there is no consensus as to what constitutes reasonable suspicion, and little direction for how mandated reporters should gauge their legal and professional responsibilities when they harbor suspicion. In this paper we outline the context of the problem, discuss the nature and scope of its conceptual underpinnings, and offer recommendations for moving towards a concrete, practical solution.     

Weathering the storm: children's long-term recall of Hurricane Andrew

Children who experienced a highly stressful natural disaster, Hurricane Andrew, were interviewed within a few months of the event, when they were 3-4 years old, and again 6 years later, when they were 9-10 years old. Children were grouped into low, moderate, or high stress groups depending on the severity of the experienced storm. All children were able to recall this event in vivid detail 6 years later. In fact, children reported over twice as many propositions at the second interview as at the first. At the initial interview, children in the high stress group reported less information than children in the moderate stress group, but 6 years later, children in all three stress groups reported similar amounts of information. However children in the high stress group needed more questions and prompts than children in the other stress groups. Yet children in the high stress group also reported more consistent information between the two interviews, especially about the storm, than children in the other stress groups. Implications for children's developing memory of stressful events are discussed.     

Sleep, dreams, and memory consolidation: the role of the stress hormone cortisol

We discuss the relationship between sleep, dreams, and memory, proposing that the content of dreams reflects aspects of memory consolidation taking place during the different stages of sleep. Although we acknowledge the likely involvement of various neuromodulators in these phenomena, we focus on the hormone cortisol, which is known to exert influence on many of the brain systems involved in memory. The concentration of cortisol escalates over the course of the night's sleep, in ways that we propose can help explain the changing nature of dreams across the sleep cycle.     

Senior capstone design and ethics: A bridge to the professional world

A senior level capstone design experience has been developed and offered with a particular emphasis on many of the professional issues raised in Accreditation Board for Engineering and Technology (ABET) Engineering Criterion IV. The course has sought to develop student awareness of the ethical foundation of the engineering profession, the global and societal framework within which engineers practice, and the environmental impact on engineering. The capstone design course also focused upon improving the technical communications skills of the graduating senior class with both extensive instruction in writing and multiple workshops dealing with the art of making an effective oral presentation. The effectiveness of the design course was assessed using Kirkpatrick’s model for evaluating training programs. An earlier version of this paper was presented at the “Ethics and Social Responsibility in Engineering and Technology” meeting, New Orleans, 2003.     

Trauma histories and attachment styles of members of the International Society for Traumatic Stress Studies

The study is focused on the training, demographics, perceived emotional and physical health, past traumatic experience histories, and attachment styles of mental health professionals in the field of trauma (members of the International Society for Traumatic Stress Studies). While the data set is limited by a low response rate of 20%, the uniqueness of the sample and distinctive themes yield insight into the experience of trauma and its association with attachment style.     

Perceptions of Ethical Behaviour among Business Faculty in Canada

Faculty members at Canadian business schools were surveyed regarding their ethical perceptions of behaviours related to undergraduate instruction. Fifty-five behavioural statements were listed and respondents were asked to rate the extent to which they felt each behaviour was ethical or unethical. The only item that respondents endorsed as unequivocally unethical (90% indicated it was definitely unethical) was Becoming sexually involved with an undergraduate in one of your classes. We also compared the results of our sample to those of an American sample. Overall, an interesting pattern of differences emerged between the responses obtained in Canada and the U.S. In general, the direction of the significant differences was such that Canadian professors viewed the behaviours in question as less ethical than did their American counterparts.     

Laterality effects in perceived spatial location of hallucination-like voices

Aydin and colleagues reported a reversal of physiological 'right-ear advantage' in a group of right-handed patients with schizophrenia, using an auditory acuity test. In schizophrenia, auditory hallucinations may appear to be spatially located inside or outside the patient's head. Here we show, using virtual acoustic space techniques, that normal right-handed subjects have a right-ear advantage for correctly locating the 'source' of hallucination-like voices as from either inside or outside the head. We propose a model for understanding lateralised, external hallucinations in schizophrenia based upon reversal of normal cortical asymmetry for auditory spatial processing.     

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.     

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.