Exploring attention-based explanations for some violations of Hick’s law for aimed movements

Choice reaction time generally increases linearly with the logarithm of the number of potential stimulus-response alternatives, a regularity known as Hick's law. Two apparent violations of this generalization, which have been reported for aimed eye movements (Kveraga, Boucher, & Hughes, Experimental Brain Research, 146, 307-314, 2002), and arm movements (Wright, Marino, Belovsky, & Chubb, Experimental Brain Research, 179, 475-496, 2007), occurred when the indicator stimulus was an abrupt change at the location that was the target of the to-be-made movement. We report two experiments that examined and rejected the hypothesis that these abrupt-onset indicator stimuli triggered a shift in exogenous attention and that this led to unusually small uncertainty effects. Each experiment compared this indicator stimulus with a single alternative: Experiment 1 tested an indicator stimulus at all locations other than the target; Experiment 2 tested a central pointer to the target. Neither alternative led to an uncertainty effect for pointing responses that was of the size typically observed for other responses using the same stimuli.     

The role of closure in defining the “objects” of object-based attention

Many recent studies have concluded that the underlying units of visual attention are often discrete objects whose boundaries constrain the allocation of attention. However, relatively few studies have explored the particular stimulus cues that determine what counts as an “object” of attention. We explore this issue in the context of the two-rectangles stimuli previously used by many investigators. We first show, using both spatial-cuing and divided-attention paradigms, that same-object advantages occur even when the ends of the two rectangles are not drawn. This is consistent with previous reports that have emphasized the importance of individual contours in guiding attention, and our study shows that such effects can occur in displays that also contain grouping cues. In our divided-attention experiment, however, this contour-driven same-object advantage was significantly weaker than that obtained with the standard stimulus, with the added cue of closure—demonstrating that contour-based processes are not the whole story. These results confirm and extend the observation that same-object advantages can be observed even without full-fledged objects. At the same time, however, these studies show that boundary closure—one of the most important cues to objecthood per se—can directly influence attention. We conclude that object-based attention is not an all-or-nothing phenomenon; object-based effects can be independently strengthened or weakened by multiple cues to objecthood.     

The influence of horizontal velocity on interlimb symmetry in normal walking

Changes in horizontal velocity (HV) are known to influence many biomechanical characteristics of human locomotion. The purpose of the present study was to investigate this phenomenon with respect to the interlimb symmetry of walking in a normal population. Peak and temporal ground reaction force data from both feet of 20 able-bodied males were collected at each of three relative velocity conditions (slow, normal and fast). These data were analyzed using of a series of 2 x 3 repeated measures ANOVAs, which revealed a high degree of interlimb (bilateral) symmetry across HV conditions despite significant intralimb (unilateral) changes. In contrast to this primary finding were two significant interaction effects for the stance time and peak vertical force at push-off measures respectively. These interactions indicated greater asymmetries at the slow HV condition with a trend toward improved symmetry at higher velocities. Although these results may provide some theoretical insight into the underlying nature of symmetry in gait, their overall magnitude does not seem to invalidate the current widespread use of symmetry assumptions in clinical and research settings today.     

La Biologie de Jean Piaget: (1896–1980) — Cohérence et Marginalité

Sans résumé     

Bubble ring play of bottlenose dolphins (Tursiops truncatus): implications for cognition

Research on the cognitive capacities of dolphins and other cetaceans (whales and porpoises) has importance for the study of comparative cognition, particularly with other large-brained social mammals, such as primates. One of the areas in which cetaceans can be compared with primates is that of object manipulation and physical causality, for which there is an abundant body of literature in primates. The authors supplemented qualitative observations with statistical methods to examine playful bouts of underwater bubble ring production and manipulation in 4 juvenile male captive bottlenose dolphins (Tursiops truncatus). The results are consistent with the hypothesis that dolphins monitor the quality of their bubble rings and anticipate their actions during bubble ring play.     

Psychology as a Science of Subject and Comportment,beyond the Mind and Behavior

The turn of qualitative inquiry suggests a more open, plural conception of psychology than just the science of the mind and behavior as it is most commonly defined. Historical, ontological and epistemological binding of this conception of psychology to the positivist method of natural science may have exhausted its possibilities, and after having contributed to its prestige as a science, has now become an obstacle. It is proposed that psychology be reconceived as a science of subject and comportment in the framework of a contextual hermeneutic, social, human behavioral science. Thus, without rejecting quantitative inquiry, psychology recovers territory left aside like introspection and pre-reflective self-awareness, and reconnects with traditions marginalized from the main stream. From this perspective psychology might also recover its credibility as a human science in view of current skepticism.     

Hyperreflexivity as a condition of mental disorder: a clinical and historical perspective

Hyperreflexivity, understood as intensified self-consciousness in which subjects disengage from normal forms of involvement with nature and society, often considering themselves as objects of focal awareness, is proposed here as a condition of mental disorders, without which they would not exist. This thesis is argued from a dual perspective: clinical and historical. In the clinical perspective, it is shown that hyperreflexivity is not merely concomitant with mental disorders, but indeed has causal priority over them. Empirical evidence of a correlational, experimental and therapeutic nature, or deriving from cultural change, supports this claim of causal priority. In the historical perspective, it is shown that hyperreflexivity depends on certain historical-cultural circumstances that have prevailed since the Renaissance. These circumstances have to do with the emergence of the modern subject, displaced, autonomous and condemned to a hapless 'interior journey'. This means that mental disorders as such would not have existed prior to that era. Nor in the wake of the Renaissance would mental disorders automatically come into being, depending as they do on a reflexive, institutional clinical context, which would not emerge until practically the nineteenth century, but which would extend swiftly from then on.     

Thought-action fusion: a comprehensive analysis using structural equation modeling

Thought-action fusion (TAF), the phenomenon whereby one has difficulty separating cognitions from corresponding behaviors, has implications in a wide variety of disturbances, including eating disorders, obsessive-compulsive disorder, generalized anxiety disorder, and panic disorder. Numerous constructs believed to contribute to the etiology or maintenance of TAF have been identified in the literature, but to date, no study has empirically integrated these findings into a comprehensive model. In this study, we examined simultaneously an array of variables thought to be related to TAF, and subsequently developed a model that elucidates the role of those variables that seem most involved in this phenomenon using a structural equation modeling approach. Results indicated that religiosity, as predicted by ethnic identity, was a significant predictor of TAF. Additionally, the relation between ethnic identity and TAF was partially mediated by an inflated sense of responsibility. Both TAF and obsessive-compulsive symptoms were found to be significant predictors of engagement in neutralization activities. Clinical and theoretical implications are discussed.     

Steven M. Emmanuel,Kierkegaard and the Concept of Revelation

International Journal for Philosophy of Religion -     

Neuropsychological and Behavioral Effects of Antiepilepsy Drugs

Antiepilepsy drugs work by decreasing neuronal irritability, which may also result in the non-desired side effect of decreased neuropsychological function. In addition to cognitive side effects, antiepilepsy drugs (AEDs) may be associated with behavioral effects which may range from irritability and hyperactivity to positive psychotropic effects on mood. There have been many new medications released since the 1990s, and although they tend to have more favorable side effect profiles compared to their older counterparts, there continues to be a risk of decreased cognitive function with the majority of these agents. The effects of in utero antiepilepsy drug exposure are increasingly being investigated, and differential drug risk is beginning to be described for both anatomic and cognitive outcomes. Patients with epilepsy undergoing neuropsychological evaluations are commonly on AEDs, and it is important for the clinician to recognize the potential contribution of AED therapy to neuropsychological profiles. The present article serves to provide an overview of our current understanding regarding the risks of antiepilepsy drug use for both cognitive and behavioral side effects.