The optimal time window of visual-auditory integration: a reaction time analysis.
Bottom Line:
Our approach is in line with the well-established framework for modeling multisensory integration as (nearly) optimal decision making, but none of those studies, to our knowledge, has considered reaction time as observable variable.Possible variants of the theory to account for judgments of crossmodal simultaneity are discussed.Finally, neural underpinnings of the theory in terms of oscillatory responses in primary sensory cortices are hypothesized.
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PubMed Central - PubMed
Affiliation: Department of Psychology, University of Oldenburg Oldenburg, Germany.
ABSTRACT
THE SPATIOTEMPORAL WINDOW OF INTEGRATION HAS BECOME A WIDELY ACCEPTED CONCEPT IN MULTISENSORY RESEARCH: crossmodal information falling within this window is highly likely to be integrated, whereas information falling outside is not. Here we further probe this concept in a reaction time context with redundant crossmodal targets. An infinitely large time window would lead to mandatory integration, a zero-width time window would rule out integration entirely. Making explicit assumptions about the arrival time difference between peripheral sensory processing times triggered by a crossmodal stimulus set, we derive a decision rule that determines an optimal window width as a function of (i) the prior odds in favor of a common multisensory source, (ii) the likelihood of arrival time differences, and (iii) the payoff for making correct or wrong decisions; moreover, we suggest a detailed experimental setup to test the theory. Our approach is in line with the well-established framework for modeling multisensory integration as (nearly) optimal decision making, but none of those studies, to our knowledge, has considered reaction time as observable variable. The theory can easily be extended to reaction times collected under the focused attention paradigm. Possible variants of the theory to account for judgments of crossmodal simultaneity are discussed. Finally, neural underpinnings of the theory in terms of oscillatory responses in primary sensory cortices are hypothesized. No MeSH data available. |
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Mentions: Figure 1 illustrates the optimal time window width as a function of the prior probability P(C = 1) and the exponential parameter μ. Increasing prior probability of a common cause implies that the optimal window width increases as well; moreover, for a fixed and not too small prior probability, this optimal width decreases as the likelihood for a zero arrival time difference (μ) becomes larger. The value of t0 will be positive for 1/(1 + t1μ) < P(C = 1) ≤ 1. Moreover, window width will be 0 for P(C = 1) = 1/(1 + t1μ). Thus, in this example and, in fact, whenever the likelihood ratio converges to a non-zero value for t → 0, the prediction is that the window will disappear for a small enough value of the prior, thereby providing a possibly strong model test. (Note that the crossing of the curves is merely an artifact of having to set the observation interval to a finite value.) |
View Article: PubMed Central - PubMed
Affiliation: Department of Psychology, University of Oldenburg Oldenburg, Germany.
No MeSH data available.