#abarro

by: Jed Abarro

Speech is an integral part of human life. Everywhere we go, we hear sounds and we turn these sounds into meaningful bits of information. Speech is very important because it allows for communication and even for survival. Speech perception, especially for humans, has been widely studies. One property of speech is that it is multimodal or in simpler terms, involves different senses. To most people, speech perception would simply invoke the sense of hearing because, obviously, we need to hear speech sounds in order to perceive speech. However, have you even considered that simply looking at the movements of the mouth can lead to perception of speech?

The phenomenon described above is the McGurk Effect which states that although auditory information is the main source of information for speech perception, visual information can also have an impact or influence on our ability to perceive speech. Where do we actually see the McGurk Effect? Imagine yourself partying with your friends on a Friday night with the speakers booming ever so loudly that you can barely hear what your friends are saying. In this case, one would normally make signals with one’s mouth, spelling words to communicate a message. Although auditory information is virtually absent in this situation, visual information did provide sufficient details to perceive speech. Another example is making mouth signals in a classroom silently while the professor is discussing.

In a study by Kuhl and colleagues (1991), the effect of biological sex on the McGurk Effect was explored. In his study, he divided his participants into two groups. The first group was shown incongruent videos wherein a video of a female talker was shown but was dubbed with a male voice. The second group was shown congruent videos wherein the sex of the talker matched the sex of the talker in the video. Interestingly, the data showed that there was no significant difference between the two groups showing that sex does not interfere with the integration of information from both visual and auditory modalities despite the obvious discrepancy in sex. This implies that the ability to point out details and information about the sounds produced by a talker is developed earlier on even before the system gains the ability to integrate auditory and visual information.

This study on the McGurk Effect is very interesting because it shows how the human mind and system can actually fill in the gaps (a la Gestalt Psychology) in different stimuli. One would think that the voice-sex discrepancy would actually interfere with the perception of speech but it did not really turn out that way. This study shows us how amazing our minds are at making sense of things that seem ambiguous. The power of the human minds has no known limits and there are more to be discovered in the future.

References:

Goldstein, E. (2010). Sensation and Perception (8th ed.).     Wadsworth: Cengage Learning.