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OS_19. Attention

Saturday, October 01st,   2011 [10:50 - 11:50]


OS_19.1 - Resisting auditory attentional capture: The roles of task load, pre-knowledge, and working memory capacity

Hughes, R. 1 , Hurlstone, M. 1 , Vachon, F. 2 & Jones, D. 1

1 Cardiff University
2 Université Laval, Quebec

It is well established that a sound deviating in some way from the prevailing context captures attention and thereby disrupts cognitive performance even when such performance is based on visual information. In the present study, we showed that this form of auditory distraction is resistible through the complementary action of three putatively quite distinct factors: task encoding load, foreknowledge regarding an upcoming deviation, and individual differences in working memory capacity. The disruptive impact of a voice-deviation within a task-irrelevant speech sequence (i.e., one speech token presented in a different voice from the remainder) during a visual-verbal serial recall task was eliminated both when task encoding load was increased by changing the perceptual discriminability of the to-be-remembered stimuli and also when foreknowledge regarding an upcoming deviation was provided. Moreover, extending an observation made previously using tone sequences (Sorqvist, 2010), individuals low in working memory capacity-as measured by the operation span task-showed a greater susceptibility to attentional capture by the deviation within the irrelevant speech. The results suggest that auditory distraction by attentional capture is subject to a top-down blocking mechanism.

OS_19.2 - Visual masking revisited: Number of repetitions and attention modulate priming and awareness of a masked stimulus

Atas, A. , Vermeiren, A. & Cleeremans, A.

Consciousness, Cognition and Computation Group. Université Libre de Bruxelles. Bruxelles, Belgique.

Marcel (1983) showed that repeated presentations of a masked stimulus improved priming while failing to influence perceptual awareness. However, both empirical evidence (Ferrand, 1996) as well as theoretical proposals (Cleeremans et al., 2002) predict the opposite: Increasing bottom-up strength as resulting from repeated presentation associated with a short inter-stimulus interval (500 ms or less) should also result in increasing availability to awareness. Here, we tested this prediction by manipulating the number of repetitions of a masked stimulus in a numerical priming task and in two visibility tests. To explore the influence of attention, we also compared three different task contexts in which the priming trials were performed before, after or concurrently with the visibility trials. Results showed a systematic increase of awareness with the number of repetitions, in both objective and subjective tests. However, we only obtained a repetition-dependent priming effect in the concurrent condition, suggesting the crucial role of attention. The influence of top-down factors was also illustrated by significantly smaller priming in the priming-first condition vs. the visibility-first condition. Altogether, our results do not replicate the dissociation observed by Marcel and are instead suggestive that increases in bottom-up strength are associated with increases in visibility, and hence, awareness.

OS_19.3 - Semantic effects in the Attentional Blink: Relatedness proportion modulates the P2 and the N400 components of the event-related potentials

Peressotti, F. 1 , Pesciarelli, F. 2 , Mulatti, C. 1 & Dell'Acqua, R. 1, 3

1 DPSS - University of Padova, Italy
2 Department of Biomedical Sciences, University of Modena-Reggio Emilia, Italy
3 Centre for Cognitive and Brain Science, University of Padova, Italy

Three target words (T1, T2, T3) were presented in a RSVP sequence and participants were required to report the targets at the end of the trial. T1-T2 lag was about 300 ms so that T2 was often missed (blinked) whereas T1 and T3 were almost correctly reported. In a ERP study under such conditions, Pesciarelli, et al. (2007) observed a semantic modulation of the T3-locked P2 component that was independent on the correct report of T2 and a semantic effect on the T3-locked N400 that was detected only when T2 was not blinked. The present study is aimed at exploring how these semantic effects are modulated by the context. The experimental items were mixed with filler items containing T2-T3 related pairs in one condition, and T2-T3 unrelated pairs in the other condition. The results showed that both the P2 and the N400 semantic effects were modulated by the context and independent (i.e. either one effect, or the other, or both, or none, were observed): The N400 effect for T2-reported trials was wider in the related-filler than in the unrelated-filler context whereas the P2 effect was present only in the unrelated-filler context and independent on the correct report of T2.

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