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  • Many of us have become quick to catch illusions that trick our eyes - but how often do you consider illusions of the ear?

  • Are you really able to trust your ears and the things they hear?

  • For example, listen to Greg speaking...

  • What do you hear? If you heard 'bar, bar, bar' you'd be right. But, how about now?

  • Chances are you heard 'far, far, far' this time, with an 'F'.

  • Except, you didn't - in fact, the audio didn't even change between the two videos.

  • Strange as it seems, what you hear depends on which video you are looking at.

  • Go ahead - take turns watching each video and see how the sound morphs.

  • This is a perfect example of something called the McGurk effect,

  • which shows how our visuals can alter what we believe we're hearing.

  • Now I want you to count how many times you see a circle flash on screen.

  • Lets do that once more time. Did you see it flash twice? Many people do.

  • Yet, without the sound, it becomes clear that the circle is only flashing once.

  • In this case, the sound has altered your perceived vision.

  • This next one works best with other people around. I'll play two tones, and you tell me if they are ascending or descending.

  • In other words, are the notes played from low to high, or high to low? Listen to this.

  • Which was it? How about this one?

  • Write down what you heard for each number, and let us know in the comments.

  • Chances are, if you compare with enough people, you'll all have different answers. Surprising? Try some more.

  • And this one.

  • How is it possible that you're hearing something different from others?

  • It's an auditory illusion called the Tritone Paradox.

  • It's created in such a way that the tones contains both a higher and lower frequency in them, but our brains have a preference of which to listen to.

  • Diana Deutsch, the creator of this illusion,

  • found that your geography and language from infancy all play a role in deciding this preference.

  • Finally, listen to this audio clip of a gradually climbing tune.

  • And yet, if I play the exact same clip back to you,

  • it will sound like it's only continuing to climb higher and higher.

  • I swear this is the exact same clip I just played - you can rewind that section of this video over and over and check yourself.

  • Try it! Each time you start it over, the tune is seemingly climbing even higher.

  • It's called the Shepard Tone Illusion, of which there are many variations.

  • In it, multiple sine waves are played on top of one another raising in pitch,

  • while one quickly drops down an octave as the others continue rising.

  • But our brain doesn't notice this drop, and so the clips sound like they are rising...forever!

  • These illusions may help to explain how something like music can have such a profound yet varying effect on our minds,

  • which we discuss in our new AsapTHOUGHT episode here,

  • along with the question of whether or not Music Can Save Your Life. There's a link in the description to watch it!

  • you still trust your ears?

  • Got a burning question you want answered? Ask it in the comments or on Facebook or Twitter.

  • And if you want the inside scoop on upcoming episode ideas and behind the scenes,

  • check out our personal Instagram and Twitter handles.

  • And subscribe for more weekly science videos!

Many of us have become quick to catch illusions that trick our eyes - but how often do you consider illusions of the ear?

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