Illusory illusions: the significance of fixation on the perception of geometrical illusions

Some well-known geometrical illusions disappear when the eyes are fixating and saccades are suppressed for a period of time. This disappearance is not accompanied by fading due to stabilisation of the retinal image. Any saccade made on purpose restores the illusion immediately. The fixation time after which some illusions disappeared was measured for four illusions and four subjects each. Effects of practice have been observed after measurements were repeated on successive days. Present theories of vision cannot readily explain the effect.     

The Dissociative Factor in Symptom Reports of Rheumatic Patients with and Without Fibromyalgia

The main objective of this study was to investigate the prevalence of dissociation and its relationships to symptom reporting in fibromyalgia (FM) and other rheumatic disorders (non-FM). The participants were 73 women with FM and 85 relatively matched women with other rheumatic disorders. The participants were administered the Dissociative Experiences Scale (DES), the Profile Of Mood States (POMS), and a 50-item medical checklist. The prevalence of dissociation (DES q 25) was significantly higher in FM patients(30.1%) compared to other rheumatic disorders (7.0%). Symptom reporting correlated with measures of dissociation in both patient groups (FM:R = 0.42, p < .001; non-FM:R = 0.44, p < .001), when controlled for age, depression, and anxiety. A regression analysis confirmed the strong linkage between somatic variation and dissociation. The results suggest that dissociation is a problem for a substantial segment of patients with fibromyalgia and that dissociation is related to certain physical symptoms of fibromyalgia. Dissociation offers a different perspective on medically unexplained symptoms and may need to be addressed in future research.     

Cell phone-induced failures of visual attention during simulated driving

This research examined the effects of hands-free cell phone conversations on simulated driving. The authors found that these conversations impaired driver's reactions to vehicles braking in front of them. The authors assessed whether this impairment could be attributed to a withdrawal of attention from the visual scene, yielding a form of inattention blindness. Cell phone conversations impaired explicit recognition memory for roadside billboards. Eye-tracking data indicated that this was due to reduced attention to foveal information. This interpretation was bolstered by data showing that cell phone conversations impaired implicit perceptual memory for items presented at fixation. The data suggest that the impairment of driving performance produced by cell phone conversations is mediated, at least in part, by reduced attention to visual inputs.     

The forced-choice paradigm and the perception of facial expressions of emotion

The view that certain facial expressions of emotion are universally agreed on has been challenged by studies showing that the forced-choice paradigm may have artificially forced agreement. This article addressed this methodological criticism by offering participants the opportunity to select a none of these terms are correct option from a list of emotion labels in a modified forced-choice paradigm. The results show that agreement on the emotion label for particular facial expressions is still greater than chance, that artifactual agreement on incorrect emotion labels is obviated, that participants select the none option when asked to judge a novel expression, and that adding 4 more emotion labels does not change the pattern of agreement reported in universality studies. Although the original forced-choice format may have been prone to artifactual agreement, the modified forced-choice format appears to remedy that problem.     

Style in Philosophy: Part I

In this article, I attempt to restore the philosophical significance of that nonformalizable, noniterable, "singular' element of natural language that I call "style." I begin by critically addressing the exclusion of such instances of natural language by both semantics-oriented logical analysis and a restricted variation of structuralist linguistics. Despite the obvious advantages – with regard to style – of "pragmatic"approaches to language, such pragmatism merely returns to rule-determination in the guise of "normativity." Although style by definition resists any kind of rule-determination – whether posed in terms of semantics or intersubjective regulations of speech-acts – there can be no consideration of language that ignores the persistence of style in natural language. In terms of cognition, any discursive agent understands more than allowed by either semantics or speech-act theory. I ascribe this element of excessive signification to the role of style. My principal thesis is twofold: (1) a hermeneutic approach (exemplified by Schleiermacher) to literature should reveal the heuristically decisive role played by style in philosophy; and, more radically still, (2) style, in fact, may be crucially determinative of philosophical discourse in general. I suggest that a closer scrutiny of the lesser-known works of Ludwig Wittgenstein, conventionally regarded as having dreamt of a "philosophy without style," may consolidate the restoration of style's philosophical import.     

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.     

Checkliste zur Bewertung der wissenschaftlichen Qualität kontrollierter psychotherapeutischer Interventionsstudien (CPI)

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A remote-controlled device for long-term blood collection from freely moving, socially housed animals

A remote-controlled device was developed for injection of fluids and collection of blood samples from freely moving, socially housed animals via an indwelling catheter. Samples are collected at times chosen by the investigator, and the animal is not aware that sampling is occurring. This technique allows measurement of plasma catecholamines and other substances that fluctuate rapidly, are affected by psychosocial stimuli, and are altered by capture and other stressful activities that often accompany sample collection. Rapid retrieval of samples is facilitated by remote-controlled injection of an anesthetic. The device has been used to collect blood from dominant and subordinate male baboons before and during events such as chases and presentation of food treats. Heart rate and blood pressure were measured via radio telemetry, and behavior was recorded on videotapes. This technique allowed construction of multifaceted physiological profiles of social roles and behaviors.