In a noisy environment, we often need to integrate various sources of information, including spatial, temporal, and semantic cues between multiple signals to build a coherent representation for the target sensory events.
Among all forms of cross-modal interactions, audiovisual processing remains a main vehicle for perceiving the events in the world. Auditory and visual events often happen concurrently, and how they group together can have a strong effect on what is perceived.
As a result, researchers from three research institutes (university) worked together to have examined how competitive auditory inputs modulated the ambiguous percept of visual apparent motion. They extended the investigation of the relation between auditory grouping and multisensory integration from simple auditory stimuli configurations to more complex and perceptually competitive auditory environment.
To achieve this, researchers juxtaposed auditory gap transfer illusion with visual Ternus display. The Ternus display involved a multi-element stimulus that could induce either of two different percepts of apparent motion: 'element motion' or 'group motion'.
In 'element motion', the endmost disk was seen as moving back and forth while the middle disk at the central position remained stationary. Meanwhile, in 'group motion', both disks appeared to move laterally as a whole.
The gap transfer illusion referred to the illusory subjective transfer of a short gap (around 100 ms) from the long glide to the short continuous glide when the two glides interceded at the temporal middle point.
In their experiments, observers were required to make a perceptual discrimination of Ternus motion in the presence of concurrent auditory glides (with or without a gap inside). Results showed that a gap within a short glide imposed a remarkable effect on separating visual events, and led to a dominant perception of group motion as well.
The auditory configuration with gap transfer illusion triggered the same auditory capture effect. Further investigations showed that visual interval which coincided with the gap interval (50-230 ms) in the long glide was perceived to be shorter than that within both the short glide and the gap-transfer' auditory configurations in the same physical intervals (gaps).
Results indicated that auditory temporal perceptual grouping takes priority over the cross-modal interaction in determining the final readout of the visual perception, and the mechanism of selective attention on auditory events also plays a role.
Funding for this research came from the Natural Science Foundation of China (11174316, 31200760, 41374147), National High Technology Research and Development Program of China (863 Program; 2012AA011602) and Strategic Priority Research Program of the Chinese Academy of Sciences (XDA06020201).
References:
WANG Qingcui, GUO Lu, BAO Ming, CHEN Lihan. Perception of Visual Apparent Motion Is Modulated by a Gap within Concurrent Auditory Glides, Even When It Is Illusory. Frontiers in Psychology (Vol. 6, pp. 564-564, May 2015). http://dx.doi.org/10.3389/fpsyg.2015.00564
Contact:
BAO Ming
Institute of Acoustics, Chinese Academy of Sciences, 100190 Beijing, China
Email: baoming@mail.ioa.ac.cn