Visual Distractors Disrupt Audiovisual Integration Regardless of Stimulus Complexity

Abstract

The intricate relationship between multisensory integration and attention has been extensively researched in the multisensory field; however, the necessity of attention for the binding of multisensory stimuli remains contested. In the current study, we investigated whether diverting attention from well-known multisensory tasks would disrupt integration and whether the complexity of the stimulus and task modulated this interaction. A secondary objective of this study was to investigate individual differences in the interaction of attention and multisensory integration. Participants completed a simple audiovisual speeded detection task and McGurk task under various perceptual load conditions: no load (multisensory task while visual distractors present), low load (multisensory task while detecting the presence of a yellow letter in the visual distractors), and high load (multisensory task while detecting the presence of a number in the visual distractors). Consistent with prior studies, we found that increased perceptual load led to decreased reports of the McGurk illusion, thus confirming the necessity of attention for the integration of speech stimuli. Although increased perceptual load led to longer response times for all stimuli in the speeded detection task, participants responded faster on multisensory trials than unisensory trials. However, the increase in multisensory response times violated the race model for no and low perceptual load conditions only. Additionally, a geometric measure of Miller’s inequality showed a decrease in multisensory integration for the speeded detection task with increasing perceptual load. Surprisingly, we found diverging changes in multisensory integration with increasing load for participants who did not show integration for the no load condition: no changes in integration for the McGurk task with increasing load but increases in integration for the detection task. The results of this study indicate that attention plays a crucial role in multisensory integration for both highly complex and simple multisensory tasks and that attention may interact differently with multisensory processing in individuals who do not strongly integrate multisensory information.

Characterization of Noise Signatures of Involuntary Head Motion in the Autism Brain Imaging Data Exchange Repository

“…To that end, we compare different families of probability distributions (e.g., the Gaussian, Normal, Lognormal, Exponential and Gamma) and choose the best fit in an MLE sense. Owing to our prior works using the ABIDE sets (Torres and Denisova, 2016 ; Torres et al, 2017 ) we determined that the Gamma had the best fit in an MLE sense. As such, we settled on the continuous Gamma family of probability distributions (Ross, 1983 ).…”

“…The variable degree of skewness we have previously found in the empirical distributions of linear and angular speed peaks derived from these ABIDE data (Torres et al, 2017 ) sets motivated us to further explore the possibility that different random processes may underlie the time series data collected under different SR. As such, here we try to elucidate the quality of the noise inherently present in the variability of the speed-dependent raw data comprising all the original frames of the studies of ABIDE (i.e., without scrubbing the images).…”

“…Further, open access to these data has opened new avenues for replication and critical assessment regarding the reliability of clinical tests reported in the demographic data. Among such tests are the ADOS-2 and ADOS-G scores, IQ and medication status (Torres and Denisova, 2016 ; Torres et al, 2017 ).…”

“…Given individual differences in the amount of involuntary motions such as those of the head at rest, such gaps can vary by participant. As such, given a study with different demographics (e.g., autism and age-matched neurotypical controls in Appendix Figure A1 ) and owing to the excess motion in autism (Torres and Denisova, 2016 ; Torres et al, 2017 ), we would be comparing very disparate sizes of overall number of the clean image frames selected to be included in further analyses. In this way, one would be (unknowingly) skewing the statistical inference and further interpretation of the results.…”

Can Limitations of Visuospatial Attention Be Circumvented? A Review

“…Findings of a recent study (Matusz et al, 2015 ) suggested that conclusions about the distribution of attentional resources across the sensory modalities for adults do not necessarily generalize to children. In addition, we want to note that another effective means to circumvent limitations in one sensory modality is by providing redundant information via several sensory modalities, thereby taking advantage of the behavioral benefits of multisensory integration (i.e., faster reaction times and a higher accuracy) (Meredith and Stein, 1983 ; Ernst and Banks, 2002 ; Helbig and Ernst, 2008 ; Stein and Stanford, 2008 ; Gibney et al, 2017 ). The process of multisensory integration has been argued to be independent of top-down influences (Matusz and Eimer, 2011 ; De Meo et al, 2015 ; ten Oever et al, 2016 ) and be robust against additional attentional demands (Wahn and König, 2015a , b ) for low-level stimuli (for more general reviews on the topic, see van Atteveldt et al, 2014 ; Chen and Spence, 2016 ; Macaluso et al, 2016 ; Tang et al, 2016 ), making it highly suitable to circumvent limitations within one sensory modality.…”