The McGurk Effect: Watch your ears lie to you.

Found this video and thought it was pretty interesting and worth a share. Just watch the video and see how your sight can determine what you hear.

reply to post by TV_Nation


Thank you for posting that! I love learning new things like this. You made my day

What an interesting phenomenon.

Amazing how our brains tend to impose on reality.

Thank you for posting this.

Makes me wonder what else there is that my brain is mis-interpreting as reality.

Star and flag for you, that is an amazing effect and i'd never heard of it before now.

Makes me wonder, if someone is blind, do sounds sound different to them than they do to someone who is not blind? Thanks for posting that vid op.

reply to post by TV_Nation
I've posted many times here about how unreliable human senses are.

But I didn't know about this effect!

Now I have one more example to add to my ever growing list.

And the video is right! Even when you're aware of the effect, it still works and you're not immune to it.

Thanks for posting it!

Excellent find.

And check this out -- try covering his mouth entirely with one finger. It still happens. The rest of his facial cues trigger it. I tried covering different parts of his face, and only when the entire lower half is blocked does the "F" sound go away. When blocking most but not all of it, it turns into a kind of softer "th" sound. Fascinating.

And a little bit terrifying. It's not that I don't already know how tenuous our perceptions are, but coming face to face with it like that is always unsettling. Though that is in part because the implications of what could be possible when manipulating this are rather chilling.

Now that was a floody good bind!

reply to post by TV_Nation


Thanks for the post. I am really amazed that after watching the BBC video from the Horizon show, I am somehow feeling dizzy! actual dizziness! Did anyone else get that effect from watching this? It feels alot like when your in an airplane in flight and you close your eyes and put your chin on you chest to induce vertigo! Solid !!

I heard BAA the first time and VAA the second time....
It was obvious, even from the different way he was emitting sounds using his lips the second time.
Or maybe, I got something wrong somewhere?!

Originally posted by Sarahko
I heard BAA the first time and VAA the second time....
It was obvious, even from the different way he was emitting sounds using his lips the second time.
Or maybe, I got something wrong somewhere?!

Your either very confused or you got it right completely!

The point of the video is this: The actual sound is the exact same sound over and over again. The ONLY difference is that you see his mouth pronouncing different sounds, and your mind "hears" different sounds based upon what you see.

If that's what you were thinking, you got it right. If you were thinking something else, then yes you got it wrong

This is quite amazing in my opinion! I knew our minds just interpreted stuff around us, instead of actually seeing/hearing/feeling what is really there, but to see that concept laid out with an example such as this is absolutely mind bending. I kept trying to NOT hear "FAA FAA FAA" over and over again and I couldn't! Just craziness I say, makes you question reality even more!

That is a great illusion which never heard about so thank You for sharing Heh this just shows how much we can really "relay" on our senses .

WoW~!!! Thank you for sharing OP! Really ineteresting video.. We knew for a long time that we cannot always trust our senses, but never quite understand how or why.. This clarifies a lot. Star and flag for you! Good Job!

I don't get it.
I only ever heard BAA, never once heard a FAA/VAA.
Does that mean I'm retarded or something?

This is disturbing to me. When I talk with someone I don't look at their eyes because I can't pay attention to their eyes and voice at the same time. So, I look at their mouths to make sure what they're saying matches what I'm hearing. What am I gonna do now? I'm doomed

Still, I only hear Baa. The image confused me but the sound didn't change.

Wow, that is truly fascinating! When they had both images side by side, I switched my focus back and forth, so it sounded like he was going ba fa ba fa.
Those of you who only heard ba well....

reply to post by TV_Nation


If I hear the word "bar" one more time I'll die and I never thought I'd say that.

The human brains often works in synchronous ways. Occasionally it overdoes itself and becomes synasthaesia, which is the occurence of automatically assigning unrelated attributes to a given stimuli such as "hearing" colour, etc. In a normal scenario, however, the brain works in harmony to produce an accurate perception of the world around us.

There are weird things with the eyes too. The human brain is just a big mess of weird.

so seeing ISN'T believing!!!! Good find! This is one to share....

While purely an auditory illusion:



Known as a Shepard Tone - I will quote a better explanation from the next video.



This is a better graphical representation of what is going on - though I believe the particular frequency range selected and the way the system is offset makes the illusion more perceptible as an illusion (if you listen to it, you will get what I mean - you can hear the 'shift').

To quote the person who posted this video:

A visualization of the Shepard-risset glissando, a type of Shepard tone.
The Shepard tone is named after Roger Shepard, and is a sound consisting of a superposition of pitches separated by octaves. When the fundamentals fade into and out of a frequency range, it creates the illusion of a never-ending descent and ascent in pitch (that does not ultimately go any higher or lower).

Here, we synthesized the image on screen at 48-tones per octave, fading in from pitch to pitch to create the illusion of continuity. For the three segments, we have: a downwards glissando on the horn centered at 275Hz, an upwards glissando on the triangle wave centered at 330Hz, and a downwards glissando on the triangle wave centered at 330Hz.

This is what happens when people start as music majors in community college and get Masters in quantum mechanics, apparently. I jest.

There are a number of other audio illusions out there.

This is interesting. Thank you for sharing (first post on ATS )

I've found many illusions in my day but this is something I haven't come across before.

As for the shepard tone, interesting, but once you see the visualization the 'magic' of the illusion wears off, and you can actually hear the 'illusion' where as with the audio-visual effect it doesn't fade away even with knowledge of the illusion. I think this is what separates these two illusions. I wonder what practical applications there are to this audio-visual illusion?