Temporal binding, binocular rivalry, and consciousness.

Cognitive functions like perception, memory, language, or consciousness are based on highly parallel and distributed information processing by the brain. One of the major unresolved questions is how information can be integrated and how coherent representational states can be established in the distributed neuronal systems subserving these functions. It has been suggested that this so-called "binding problem" may be solved in the temporal domain. The hypothesis is that synchronization of neuronal discharges can serve for the integration of distributed neurons into cell assemblies and that this process may underlie the selection of perceptually and behaviorally relevant information. As we intend to show here, this temporal binding hypothesis has implications for the search of the neural correlate of consciousness. We review experimental results, mainly obtained in the visual system, which support the notion of temporal binding. In particular, we discuss recent experiments on the neural mechanisms of binocular rivalry which suggest that appropriate synchronization among cortical neurons may be one of the necessary conditions for the buildup of perceptual states and awareness of sensory stimuli.     

Towards a New Epistemology of Mathematics

In this introduction we discuss the motivation behind the workshop “Towards a New Epistemology of Mathematics” of which this special issue constitutes the proceedings. We elaborate on historical and empirical aspects of the desired new epistemology, connect it to the public image of mathematics, and give a summary and an introduction to the contributions to this issue.

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When does between-sequence phonological similarity promote irrelevant sound disruption?

Typically, the phonological similarity between to-be-recalled items and TBI auditory stimuli has no impact if recall in serial order is required. However, in the present study, the authors have shown that the free recall, but not serial recall, of lists of phonologically related to-be-remembered items was disrupted by an irrelevant sound stream (end rhymes) sharing similar phonological content. These findings can be explained by the notion that between-sequence phonological similarity effects emerge when category-cueing processes become an important determinant for recall, such as when shared category information can be used as a retrieval aid to cue list items or plausible list candidates. In this case, the presence of categorically similar irrelevant items impairs the retrieval of list items and leads to intrusion error. Implications of these results for theories of auditory distraction are discussed.     

Utilitarian relevance and face management in the interpretation of ambiguous question/request statements

Often, requests are made in an indirect manner and phrased in such a way that they can also be construed as questions. For example, the sentence “Is there any coffee left?” can be construed either as a question about coffee or as a request for coffee. This article offers a combined test of some key predictions of two approaches to the disambiguation of question/request statements: (1) the face management approach, which gives a prominent role to variables such as status and potential loss of face; and (2) the utilitarian relevance approach, which gives a prominent role to the goals pursued by the speaker at the time he or she issues the statement. Ambiguous question/request statements provide a natural test bed for the latter approach in particular. A board game paradigm is developed to allow for a clean, orthogonal manipulation of all variables. The results wholly support the utilitarian relevance approach and offer new perspectives on the face management approach.     

Bypassing the central bottleneck after single-task practice in the psychological refractory period paradigm: Evidence for task automatization and greedy resource recruitment

In this research, the controversial issue of whether the central bottleneck can be bypassed through task automatization was investigated. To examine this issue, participants received six single-task practice sessions with an auditory-vocal task (low vs. high pitch). We then assessed dual-task performance using the analytically tractable psychological refractory period (PRP) paradigm, in which the highly practiced auditory-vocal task was presented as Task 2, along with an unpracticed visual-manual Task 1. The results provide evidence of bottleneck bypass for virtually all the participants (17 out of 20). Several converging tests suggest that the bottleneck reemerged, however, in a follow-up experiment with tasks presented in the opposite order (auditory-vocal Task 1 and visual-manual Task 2). One possible explanation is that tasks greedily recruit central resources when available, even though they can operate without central resources when unavailable.     

Summarizing digital documents: effects of alternate or simultaneous window display

We investigated the effect of window visibility on the computer‐based summarizing of digital documents. Two experiments studied the impact of the simultaneous or alternate display of the windows containing the notepad and source documents. In Experiment 1, the participants were asked to summarize the content of the source documents. In Experiment 2, they were required to copy out sections of the source documents. The results showed that in the alternate condition, the participants performed fewer reading and writing cycles than in the simultaneous condition. Furthermore, in the alternate condition, the writing episodes were both more numerous and more effortful, while quality of the summaries produced using the copying strategy was also affected. These experiments highlight the need for writers to be able to navigate freely and easily between the windows so that they can construct an overall mental representation of their summaries. Copyright © 2007 John Wiley & Sons, Ltd.     

Modality-specific and amodal sources of interference in the attentional blink

When two masked targets (T1 and T2) are visually or auditorily presented in rapid succession, processing of T1 produces an attentional blink (AB)--that is, a transient impairment of T2 identification. The present study was conducted to compare the relative impact of masking T1 and T2 between vision and audition. Within a rapidly presented sequence, each of the two verbal targets, discriminated by their offset (Experiment 1) or their onset (Experiment 2), could be followed by either a single item, acting as a mask, or a blank gap. Masking of T2 appeared to be necessary for the occurrence of the AB for both the visual and the auditory modality. However, whereas masking of T1 affected the expression of the visual AB in both experiments, the same effect was observed in the auditory modality only when the targets varied at the onset. These results provide further evidence that processing auditory and visual information is restricted by similar attentional limitations but also suggest that these limits are constrained by properties specific to each sensory system.     

Quantifying continuous exercise using the ratio of work completed to endurance limit associated with exercise-induced delayed-onset muscle soreness

This study quantified training load of various exercises using a novel method developed by the authors and based on the ratio of work completed: endurance limit, associated with exercise-induced delayed-onset muscle soreness. Exercises were also quantified using the Training Impulse method. 8 runners performed a marathon and a 60-min. run at marathon velocity, and 9 rowers performed two maximal exercises (500 m and 2000 m) on a rowing ergometer. To examine the validity of the two methods, the relationships between the training loads provided by the Training Impulse and the Authors' methods, the direct comparison of the tasks performed, and the usability of the Authors' method components in regular training were assessed. Authors' method was significantly related to Training Impulse method (r = .83, p < .05) and was higher for running (r = .94, p < .05) but none was observed for rowing. In both methods, the marathon run resulted in high training load compared with the other tasks. When compared with the 60-min. run, the training load of the 2000-m row was slightly higher for the Authors' method, but lower for Training Impulse method. In the Authors' method, the delayed-onset muscle soreness component discriminates the marathon from the other tasks whereas the ration of work completed: endurance limit differentiates the 60-min. run from the 2000-m row. The duration component of the Training Impulse method could lead to overestimation of the training load of prolonged exercises compared with high intensity exercise. The relationship between the Training Impulse and the Authors' methods for prolonged exercises, the training load provided for each task, and the components of the Authors' method supported the validity of this new tool to describe exercise-induced fatigue.     

Risk factors for addictive disorders: a discriminant analysis on 374 addicted and 513 nonpsychiatric participants

Many common risk factors have been described in addictive disorders. Little is known about factors' respective contributions to discrimination of addicted and nonaddicted participants. Two large samples were compared including 513 nonpsychiatric participants and 374 addicted participants meeting the DSM-IV criteria for eating disorders, alcohol, or substance dependence. Twenty-six risk factors were assessed by interview or self-rating scales. A discriminant analysis determined the respective weight of each risk factor. One discriminant function emerged and characterized a depressive dimension. The results suggest that the different risk factors described in addiction could be related to a depressive dimension.