Weighted integration suggests that visual and tactile signals provide independent estimates about duration.

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. Copyright and reuse: City Research Online aims to make research outputs of City, University of London available to a wider audience. Copyright and Moral Rights remain with the author(s) and/or copyright holders. URLs from City Research Online may be freely distributed and linked to. City Research Online: http://openaccess.city.ac.uk/ publications@city.ac.uk Permanent repository link: City Research OnlineThe APA has copyright on this article. When published, it can be found at: improvements can be predicted quantitatively, assuming estimates are combined by summation, a process described as optimal when summation is weighted in accordance with the variance associated with each of the initially independent estimates. We assessed this possibility for visual and tactile information regarding temporal intervals. In Experiment 1, 12 musicians and 12 nonmusicians judged durations of 300 and 600 ms, compared to test values spanning these standards.Bimodal precision increased relative to unimodal conditions, but not by the extent predicted by optimally weighted summation. In Experiment 2, six musicians and six other participants each judged six standards, ranging from 100 ms to 600 ms, with conflicting cues providing a measure of the weight assigned to each sensory modality. A weighted integration model best fitted these data, with musicians more likely to select near-optimal weights than non-musicians. Overall, data were consistent with the existence of separate visual and tactile clock components at either the counter/integrator or memory stages. Independent estimates are passed to a decisional process, but not always combined in a statistically optimal fashion. Statement of public significanceWe are able to judge the duration of events as they unfold (e.g. the time for which somebody holds our gaze). Sometimes, this information is conveyed to several of our senses at once (e.g. both seeing and feeling the duration of a caress). Theorists argue about whether time intervals are calculated separately for each sense, or rely on a common centralised timer. This study suggests that when people experience the duration of events via both vision and touch, they gain a multisensory benefit, performing better than when they receive just visual or just tactile stimulation.This kind of benefit can only accrue if time is first estimated independently within each sense, suggesting that separate timers exist.Humans and other animals express their ability to time intervals through a wide variety of behaviours. In the lab, this ability is often assessed by requiring experimental participants to make judgments about the duration of events. However, our knowledge regarding the neurocognitive bases of these judgments remains hazy. One debate concerns the centralised versus distributed nature of the hypothetical internal clock or clocks (Ivry & Schlerf, 2008;Ivry & Spencer, 2004 Revina, Bruno, & Johnston, 2012;and Morgan...

Auditory and Visual Durations Load a Unitary Working-Memory Resource

“…Although these are not directly comparable to estimates from other kinds of task/analyses, these are broadly in line with previous research using untrained participants on different tasks (e.g. Ball et al, 2017;Narkiewicz, Lambrechts, Eichelbaum, & Yarrow, 2015), and they are a little above the more exactly equivalent estimates from work adopting a similar approach (but with more practised participants, with no memory manipulation; Acerbi et al, 2012). A parameter recovery simulation (Appendix B) indicated that Weber ratios could be recovered successfully using our methods.…”

“…Previous work (e.g. Ball et al, 2017;Hartcher-O'Brien et al, 2014) has suggested that information about duration can be combined from each of the unimodal signals comprising a bimodal stimulus, improving precision. Hence the noise that limits performance must, at some level, be independent for each modality.…”

“…Ball, Arnold, & Yarrow, 2017;Hartcher-O'Brien, Di Luca, & Ernst, 2014;Heron et al, 2012). For example, Ball et al (2017) found an improvement in precision for visuotactile bimodal stimuli, compared to unimodal stimuli from either modality. This finding implies that independent sources of noise might limit the precision of tactile and visual duration judgements, such that averaging can improve performance in the bimodal case.…”

“…However, other behavioural evidence suggests that stimulus durations might be processed by modality-specific mechanisms (e.g. Ball, Arnold, & Yarrow, 2017;Hartcher-O'Brien, Di Luca, & Ernst, 2014;Heron et al, 2012). For example, Ball et al (2017) found an improvement in precision for visuotactile bimodal stimuli, compared to unimodal stimuli from either modality.…”

Activity in perceptual classification networks as a basis for human subjective time perception

“…50,51 ), suggesting the possibility to implement the same mechanism in models for auditory classification. This additional level of redundancy in estimation would likely improve performance for scenarios that include both visual and auditory information, as has been shown in other cases where redundant cues from different modalities are combined 23,52–54 . Additional redundancy in estimation would also likely reduce the propensity for the model to overestimate in scenarios that contain many times more perceptual changes than expected (such as indicated by the difference between human and model scene-wise biases Fig.…”