Do audiovisual illusions like McGurk Effect only apply to speech?

Submitted by knowledgeisnone t3_110jpbz in askscience

For example, if say someone pretended to hit their head, but in reality I just subtlety made a bumping noise, would people percieve it as if the noise came from the person who 'hit their head'?

this is a dumb example, but im basically wondering is the audio illusion from overall associations of sounds with the things that make the sounds, or is it with only speech recognition?

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synaptome t1_j8af3a8 wrote

It does not. The McGurk effect is a cross modal illusion, which happens when one of your senses “hack” another. Speech is cross modal, hence the illusion, it works very well with anything visual/auditory and in theory it should with other senses (less obvious though). Here is a famous non speech example. In the case of the McGurk, visual information is processed more rapidly, which triggers an oscillatory response from the visual area. The auditory information does the same in auditory cortex. At some point, both are supposed to be integrated into one big coherent audiovisual perception, which is speech. But since the auditory information is lagging, if the visual information is slightly different, it will shift the oscillatory response toward the perception matching the visual information.

Source: I’m a neuroscientist and I worked on the McGurk effect.

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NorwegianGlaswegian t1_j8b4sfi wrote

Replying to synaptome (#1,791,107)

It seems like a fascinating illusion; kind of wish that I were capable of experiencing it. I have autism spectrum disorder and have wondered why it's common for people with ASD to be immune to the McGurk effect, and if it has been possible to explore the reasons for this.

I have wondered if our tendency to be hyposensitive and/or hypersensitive to different kinds of sensory stimuli (not to mention difficulty parsing sensory information) might prevent certain forms of perceptual phenomena from occuring, or if a deficit or difference in some other area is a more salient factor.

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Current-Ad6521 t1_j8hntmc wrote

No, for example -people often hear a thudding type noise when they see something that looks like it is landing hard and causing vibration but not actually making noise

If you know about the concept of neuroplasticity -it has an effect on what noises we hear and causes what are kind of illusions. Native Hindi speakers can discern two different 'd' noises that sound the same to people who did not grow up hearing Hindi. English speakers can very easily discern the words "pen" and "pin" but many language speakers dissimilar to English cannot. German people who did not grow up hearing English (which today is essentially none of them) often could not perceive "th" sounds -if you've heard stereotypical German accents where "the" is pronounced like "ze", it is based on this -back in the day German people usually couldn't hear th sounds

If you've ever heard someone trying to learn a language or tried to learn a language yourself and just not been able to get certain sounds right -this is often why. When the brain did not grow connections to be able to perceive certain sounds, you cannot hear them and your brain creates an illusion of a sound you do know.

There are also tons of visual illusions that we perceive 24/7 the time but do not notice

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