Visual masking and RSVP reveal neural competition

A test visual stimulus is harder to recognize when another stimulus is presented in close temporal vicinity; presenting stimuli in close spatial vicinity of a test stimulus reduces its visibility; presenting a stimulus to one eye can render invisible another stimulus presented to the other eye; and perceiving one interpretation of an ambiguous image prevents the simultaneous perception of other visual interpretations. A single, neurophysiological theory, which may be called 'neural competition' might explain all these phenomena: when two alternative neural visual representations co-exist in the brain, they compete against each other.     

Issues in diagnosing anxiety disorders

Research progress in the anxiety disorders is predicated on a useful classification system. In this paper, we review the reliability and validity data for theDiagnostic and Statistical Manual of Mental Disorders, 3rd ed. (DSM-III) anxiety disorders and discuss the salient issues associated with both the conceptualization of anxiety disorders and the diagnostic criteria offered in the DSM-III. It is concluded that the diagnostic reliability for these disorders is, overall, satisfactory. A dearth of validity data, however, hinders progress in both the diagnosis and the treatment of the anxiety disorders. Nevertheless, the DSM-III work group has proposed several changes in the diagnostic criteria for the anxiety disorders. We find some of these proposed changes helpful in that they clarify current diagnostic criteria; changes in diagnostic criteria that alter the basic classification schema, however, seem to be premature.Preparation of this paper was supported in part by MIMH Research Grant 1368.On sabbatical leave from Indiana State University.     

Reasonable Partiality Towards Compatriots

Ethical theories normally make room both for global duties to human beings everywhere and special duties to those we are attached to in some way. Such a split-level view requires us to specify the kind of attachment that can ground special duties, and to explain the comparative force of the two kinds of duties in cases of conflict. Special duties are generated within groups that are intrinsically valuable and not inherently unjust, where the duties can be shown to be integral to relationships within the group. Since nations can be shown to meet these conditions, acknowledging special obligations towards compatriots is justified. However for such partiality to be reasonable, it must be balanced against recognition of duties of global justice. These duties include duties to respect human rights and duties of fairness towards non-nationals. Weighing such duties against domestic duties of social justice is not a simple task, and the outcome should depend on the precise specification of the duty at stake. In particular, the duty to respect human rights fragments into four sub-duties whose force when set against local duties is markedly different.     

The involvement of bottom-up saliency processing in endogenous inhibition of return

Participants are faster at detecting a visual target when it appears at a cued, as compared with an uncued, location. In general, a reversal of this cost-benefit pattern is observed after exogenous cuing when the cue-target interval exceeds approximately 250?ms (inhibition of return [IOR]), and not after endogenous cuing. We suggest that, usually, no IOR is found with endogenous cues because no bottom-up saliency-based orienting processes are claimed. Therefore, we developed an endogenous feature-based split-cue task to allow for endogenous saliency-based orienting. IOR was observed in the saliency-driven endogenous cuing condition, and not in the control condition that prevented saliency-based orienting. These results suggest that usage of saliency-based orienting processes in either endogenous or exogenous orienting warrants the appearance of IOR.     

Differentiating emotional processing and attention in psychopathy with functional neuroimaging

Individuals with psychopathy are often characterized by emotional processing deficits, and recent research has examined the specific contexts and cognitive mechanisms that underlie these abnormalities. Some evidence suggests that abnormal features of attention are fundamental to emotional deficits in persons with psychopathy, but few studies have demonstrated the neural underpinnings responsible for such effects. Here, we use functional neuroimaging to examine attention–emotion interactions among incarcerated individuals (n = 120) evaluated for psychopathic traits using the Hare Psychopathy Checklist–Revised (PCL-R). Using a task designed to manipulate attention to emotional features of visual stimuli, we demonstrate effects representing implicit emotional processing, explicit emotional processing, attention-facilitated emotional processing, and vigilance for emotional content. Results confirm the importance of considering mechanisms of attention when evaluating emotional processing differences related to psychopathic traits. The affective-interpersonal features of psychopathy (PCL-R Factor 1) were associated with relatively lower emotion-dependent augmentation of activity in visual processing areas during implicit emotional processing, while antisocial-lifestyle features (PCL-R Factor 2) were associated with elevated activity in the amygdala and related salience network regions. During explicit emotional processing, psychopathic traits were associated with upregulation in the medial prefrontal cortex, insula, and superior frontal regions. Isolating the impact of explicit attention to emotional content, only Factor 1 was related to upregulation of activity in the visual processing stream, which was accompanied by increased activity in the angular gyrus. These effects highlight some important mechanisms underlying abnormal features of attention and emotional processing that accompany psychopathic traits.     

Temporal contiguity and the judgement of causality by human subjects

Three experiments examined the role of the degree of temporal contiguity between an action and an outcome in human causality judgement. In all the experiments subjects were required to perform an action—pressing a key on a computer keyboard—and to judge the extent to which the action caused an outcome on the computer screen to occur. The action and outcome occurred on a free-operant schedule. In the first experiment a 2-sec delay between the action and outcome reduced causality judgements relative to a situation in which there was no delay. In the second experiment judgements in conditions with delays of 0, 4, 8, and 16 sec were compared with judgements in conditions in which the same pattern of outcomes occurred non-contingently with respect to the subjects' responding. In both of these experiments the events were controlled by random ratio schedules, following the procedure of Wasserman, Chatlosh, and Neunaber (1983), in which each condition was divided into 1-sec intervals. In the third experiment judgements in conditions with delays of 0, 2, 4, or 8 sec were compared in a continuous procedure rather than one divided into 1-sec intervals. In all experiments the increasing delays led to progressively lower judgements of causality. The results are related to three accounts of the mechanism underlying human causality judgement and are also compared with results from analogous animal conditioning studies.