Auditory enhancement of illusory contour perception
AUTHORS: Tivadar RI, Gaglianese A, Murray MM
Multisensory Research, 34(1): 1-15, June 2020
Illusory contours (ICs) are borders that are perceived in the absence of contrast gradients. Until recently, IC processes were considered exclusively visual in nature and presumed to be unaffected by information from other senses. We addressed this knowledge gap. Healthy adults (N=15) completed an IC presence vs. absence discrimination task with low contrast inducer stimuli, which were masked, as well as with continuous background acoustic noise. Half of the trials included a 1000Hz tone presented synchronously with the inducer stimuli. Accuracy in IC processing was significantly higher when tones were synchronously present, and there was no such corresponding effect when ICs were absent (significant IC presence/absence × Sound presence/absence interaction). These results provide the first demonstration that multisensory processes augment mid-level vision perceptual functions exemplified by IC processes. Aside from the impact on neurobiological and computational models of vision our findings may prove clinically beneficial for low-vision or sight-restored patients.