Tuesday, 9 June 2015
The McGurk Effect: An Auditory Illusion
This week’s post will be brief, so that you can get out and enjoy the start of summer and the restoratjve effects of nature, but the subject is very intriguing.
Have you ever heard of the McGurk effect? It’s an auditory illusion that shows just how much our brains construct our auditory perceptions not only from what we hear but also from what we see.
In the case of spoken words, what we see is the mouth of the person who is talking to us.
If you watch a video where, on the audio track, someone is actually saying “ba”, but in the image, their mouth is pronouncing the sound “fa”, the sound “fa” is what you’ll hear. But if you then look away from the screen and play the video again, you’ll hear “ba”!
Even Lawrence Rosenblum, the researcher who made the video at the first link below, who has been studying this illusion for 25 years, and who has observed it thousands of times still gets fooled every time. It is the auditory equivalent of numerous optical illusions, such as Adelson’s checkerboard, where even when you have been shown the proof, it is hard to believe that the two adjacent squares are the same shade of grey.
In other words, certain circuits in our brain are so “hard-wired” that our poor little rational minds haven’t got a chance!