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!
So...do 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!