Author Manuscript Author ManuscriptWe have developed a novel experimental paradigm for
Author Manuscript Author ManuscriptWe have created a novel experimental paradigm for mapping the temporal dynamics of audiovisual integration in speech. Especially, we employed a phoneme identification job in which we overlaid McGurk stimuli with a spatiotemporally correlated visual masker that revealed crucial visual cues on some trials but not on others. As a result, McGurk fusion was observed only on trials for which essential visual cues were obtainable. Behavioral patterns in phoneme identification (fusion or no fusion) were reverse correlated with masker patterns more than a lot of trials, yielding a classification timecourse of your visual cues that contributed considerably to fusion. This strategy supplies many positive aspects over strategies made use of previously to study the temporal dynamics of audiovisual integration in speech. 1st, as opposed to temporal gating (M.A. Cathiard et al 996; Jesse Massaro, 200; K. G. Munhall Tohkura, 998; Smeele, 994) in which only the initial component from the visual or auditory stimulus is presented for the participant (as much as some predetermined “gate” location), buy SPDB masking makes it possible for presentation of your entire stimulus on every single trial. Second, as opposed to manipulations of audiovisual synchrony (Conrey Pisoni, 2006; Grant Greenberg, 200; K. G. Munhall et al 996; V. van Wassenhove et al 2007), masking doesn’t demand the organic timing on the stimulus to become altered. As in the current study, 1 can choose to manipulate stimulus timing to examine modifications in audiovisual temporal dynamics relative to the unaltered stimulus. Lastly, even though approaches happen to be developed to estimate natural audiovisual timing based on physical measurements of speech stimuli (Chandrasekaran et al 2009; Schwartz Savariaux, 204), our paradigm delivers behavioral verification of such measures primarily based on actual human perception. Towards the most effective of our information, this can be the initial application of a “bubbleslike” masking process (Fiset et al 2009; Thurman et al 200; Thurman Grossman, 20; Vinette et al 2004) to a problem of multisensory integration.Atten Percept Psychophys. Author manuscript; readily available in PMC 207 February 0.Venezia et al.PageIn the present experiment, we performed classification analysis with three McGurk stimuli presented at unique audiovisual SOAs organic timing (SYNC), 50ms visuallead (VLead50), and 00ms visuallead (VLead00). Three considerable findings summarize the results. 1st, the SYNC, VLead50, and VLead00 McGurk stimuli were rated almost identically within a phoneme identification job with no visual PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/24943195 masker. Especially, each and every stimulus elicited a higher degree of fusion suggesting that all the stimuli were perceived similarly. Second, the principal visual cue contributing to fusion (peak of your classification timecourses, Figs. 56) was identical across the McGurk stimuli (i.e the position of the peak was not impacted by the temporal offset between the auditory and visual signals). Third, regardless of this truth, there have been important differences within the contribution of a secondary visual cue across the McGurk stimuli. Namely, an early visual cue that is certainly, one related to lip movements that preceded the onset with the consonantrelated auditory signal contributed drastically to fusion for the SYNC stimulus, but not for the VLead50 or VLead00 stimuli. The latter discovering is noteworthy because it reveals that (a) temporallyleading visual speech info can drastically influence estimates of auditory signal identity, and (b).
