Freeman, E. D.

Ipser, A.

City Research Online

              City, University of London Institutional RepositoryCitation: Freeman, E. D. & Ipser, A. (2016). Negatively correlated individual differences in audiovisual asynchrony. Paper presented at the AVA Xmas 2016 Meeting, 19 Dec 2016, London, UK. This is the accepted version of the paper. This version of the publication may differ from the final published version. Permanent repository link:  http://openaccess.city.ac.uk/18422/Link to 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.ukCity Research OnlineNegatively correlated individual differences in audiovisual asynchronyElliot Freeman, Alberta Ipser City, University of London, UK Sussex University, UKCognitive Neuroscience Research Unit, City University of LondonBackground / Aims Methods• Sight and sound are out of synch • Different measures of perceptual asynchrony correlate negatively  • e.g. if vision subjectively leads audition in one individual, the same individual might show an opposite visual lag in other measures of audiovisual integration. • Freeman, Ipser et al, (2013) Cortex 49  • Previously observed using McGurk and Stream/Bounce illusions, versus Temporal Order Judgement, in dual task • Goals: Generalise to different stimuli and tasks; constrain theory Results Participants 18-50, healthy with normal vision & hearing, native or fluent English; different groups tested in different tasks. Significant negative correlations a. Dual: TOJ vs Stream/Bounce b. Dual: TOJ vs McGurk c. Single: TOJ vs McGurk d. Single: Sentence comprehension rating vs alphabet ID e. Single: Sentence comprehension rating vs number ID Not significant f. Single: Word ID vs McGurk • Word vs syllable; congruent vs incongruent modalities Implications Temporal Renormalisation theory• -ve correlation: generalises across tasks and speech stimuli of varying complexity; also non-speech • not an response bias dual task • traits persist across testing sessions • -ve correlation abolished only for word ID vs McGurk:  • multiple vs single syllables?  • Supports Temporal Renormalisation • Different neural sub-networks for different tasks, e.g. McGurk vs TOJ • Each sub-networks is subject to different audiovisual asynchronies  • Event timing in each sub-network is perceived relative to the distribution of asynchronies registered across the network. tMax Performance as function of asynchronyAsynchronous lips + voice + background noise Dependent measures- Identification or comprehension rating    ➜ tMax: Asynchrony for optimal performance- Temporal order judgement (TOJ)             ➜ PSS:   Poi t of subjective simultaneity Dual (concurrent) versus Single tasks“ba, da” / “six three five”/ “oscar victor juliet” / “The birch canoe slid on the smooth planks”MANUSCRIPT ACCEPTEDACCEPTED MANUSCRIPT New constraint • To obtain -ve correlation, stimuli presented on different sessions should have comparable temporal structure. They may then recreate a similar distribution of event timings.British Academy Leverhulme

Negatively correlated individual differences in audiovisual asynchrony

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