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The influence of degraded stimuli on audio-visual integration

Siebold, A. (2009) The influence of degraded stimuli on audio-visual integration.

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Abstract:The integration of input from multiple senses is essential for maintaining an integrated picture of the external environment and can yield information about the world that is unattainable from unimodal sensory input alone. The phenomenon of multisensory integration has been subjected to detailed analyses leading to three general principles: the temporal and the spatial rule and the principle of inverse effectiveness (Stein & Meredith, 1993). The latter states that multisensory stimuli are integrated inversely proportional to the effectiveness of the best unisensory response. In an applied study, Doll and Hanna found that the simultaneous presentation of weak auditory and visual stimuli enhances recognition beyond a value that would be obtained by unimodal presentation, even when the unimodal stimuli are intact. The objective of the current experiment was to investigate whether degraded auditory and visual stimuli would influence multisensory integration in accordance with the principle of inverse effectiveness at a behavioral level, thus that the best performance is obtained for crossmodal presentation when stimuli are degraded. In a forced-choice categorization task participants were required to identify one of two objects (objects A and B) on the basis of auditory (540 Hz and 560 Hz tones), visual (a horizontal and a vertical ellipse) or audio-visual features, where the 540 Hz tone and the horizontal ellipse combined to object A and the 560 Hz tone and the horizontal ellipse represented object B. On some trials, stimulus features were partly or fully degraded. The effect of the factors Presentation Mode with three levels (auditory, visual and audio-visual) and level of Stimulus Degradation with five levels (0%, 25%, 75% and 100%) was investigated on reaction times and accuracy data. The general results reveal that audio-visual presentation is superior to unimodal presentation and that the best performance was obtained for audio-visual presentation when stimuli are moderately degraded. These data provide behavioral evidence for the principle of inverse effectiveness with degraded stimuli and suggest that for real-world situations that highly rely on recognition of noisy input from one modality, like air- and car traffic, congruent information presented via additional modalities can enhance object recognition.
Item Type:Essay (Master)
Faculty:BMS: Behavioural, Management and Social Sciences
Subject:05 communication studies
Programme:Communication Studies MSc (60713)
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