The qualia and time course of multisensory integration in the mirror box illusion
Date
2024
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Sensory information is noisy and variable, leading people to combine redundant cues from different modalities in a statistically optimal fashion to produce more accurate perception. Decisions are made over time with accumulating evidence to determine that two inputs should be combined as signals from the same source; however, this process has thus far typically been measured through scales that mask temporal patterns. Our work investigates how different aspects of stimulus congruence affect the integration of visual and proprioceptive information in the Mirror Box Illusion (MBI). Preliminary evidence from previous work indicates that some people may integrate visual and proprioceptive cues in an abrupt, categorical manner while others experience a gradual building of the illusory experience such that the sensory cues move closer together over time. In Experiment 1, hand distance and movement synchrony were varied on the horizontal (i.e., azimuthal) plane to observe how they influenced the shift of proprioceptive estimates toward a visual cue. Results found that greater congruence on both factors resulted in more integration and in more abrupt qualia. Experiment 2 operated on an angular rotational plane and manipulated spatial congruence and postural similarity to explore the proprioceptive displacement toward the visual cue. Results showed that manipulating the disparity between hands in postural angle, but not azimuthal distance, affected the magnitude of integration. Both experiments tested a novel questionnaire report measure, asking participants to introspect on the qualia of the illusory time course at the end of each trial. Experiment 1 found consistent findings for integration magnitude when qualia were defined through objective integration measures and subjective questionnaire reports, indicating construct validity. Experiment 2 produced an interesting null result regarding qualia, as participant questionnaires were unrelated to the congruency manipulations. Ultimately, the current work strongly supports that two distinct mechanisms of integration result in different qualitative experiences of the integration time course. Further, the current work indicates that cue congruity factors analogous to Bayesian Causal Inference likelihoods (i.e., bottom-up information) and priors (i.e., top-down contextual environments) influence integration magnitude, onset time, and potentially subjective qualia. ☐ Keywords: multisensory perception, sensory integration, Mirror Box Illusion, qualia
Description
Keywords
Mirror Box Illusion, Multisensory perception, Qualia, Sensory integration