Tag: auditory

This 50-Second Clip Proves Your Brain is Amazing

By Anupum Pant

There was a post I made in the past, about a popular email forward which mentioned a paragraph and it seemed like gibberish at first. But when you actually tried to read it, you were able to read is at a very normal pace. It was as if the totally mixed up spellings did not matter. Now, that wasn’t a very scientific way of going about claiming something – through an email forward. No one really knows where it came from. Certainly not from Cambridge. And right at the end of that article, the claims of that email were convincingly challenged.

What we see today is something similar, just that, it about listening, not about reading. Plus, this one, unlike the “spelling does not matter” claim, comes directly from a very reliable source – Jayatri Das, Chief bioscientist at Franklin Institute.

In an audio broadcast uploaded on soundcould, she demonstrates a very strong and fundamental trait of the human brain.

In the 50 second sound clip, she first plays a sound that is heavily distorted by a computer. You aren’t able to make any sense out of that sound. What happens next is amazing.

The sound plays again – the distorted R2D2-ish sound. Next, she plays the actual sentence which was distorted to make it sound like gibberish. The real sentence (which I won’t reveal in the text because it would ruin it for you if you read this first) is totally clear. Now, when she plays the gibberish again, somehow you are easily able to understand it!

It’s right here and you can experience it for yourself by listening (and participating) in the 50-second clip. It is a sound you literally “cannot un-hear”.

However, I had forgotten the real sentence after a couple of days, so the clip seemed to me like what it would to a fresh test subject when I listened to it again after a week. That means technically, you are able to un-hear it.

As this article from the Atlantic – where I first read about it – puts it. It is a lot like this visual experiment.

Did you happen to notice the following image that made fun of the FIFA Worldcup 2014’s logo? I’ve attached it below, if you haven’t seen it.

The image makes the logo look like a facepalm. Before this, you must have never thought of the logo to be a facepalm. But, after you see this, every time you see the actual logo, you’ll see a facepalm.

It’s amazing what the brain can do. world cup 2014 facepalm meme

Shepard Tone – An Incredible Auditory Illusion

By Anupum Pant

Here’s the thing. Go to ToneDeafTest.com and take that little test they have on their homepage. That is what you need to do first. Stop reading further if you haven’t done it yet.

Assuming you did what I asked you to do…
If you did well in the test (with a few silly mistakes which can be ignored), you’ll probably understand better what I’m talking about in the following article. Otherwise, you might miss the point.

Nevertheless, there is still a chance that you’d understand even if you are tone deaf. I’m not sure because I’m certain not tone deaf and it’s impossible for me to understand the subjective experiences of tone deaf people (I can boast that the first time I took it, I got a perfect score in that test). Anyway, that test is a fun thing to do. You’ll at least learn something about yourself.

The endless stairs and the endless tone

Everyone knows the endless stairs (in the picture below). Now, you’d think why is the author talking about a visual illusion just after he told us to take an auditory test. That is because the popular visual illusion helps you to relate better to a relatively lesser known auditory illusion.

endless stairs illusion

If you start going up on the endless stairs, you always keep moving up. Even after you come back to the same place, you still keep going up. An impossibility. But it’s something that fools your eyes. The same thing happens if you start going down the stairs.

A similar thing can happen with tones. Listen to the following (continuous?) note sweep.

It sounds like a tone that is continuously going down, endlessly. Only, it isn’t. It’s actually a much smaller looped sound that starts from a high point and then goes down. These little loops have been placed one after the other. If you do not carefully listen to it, you’ll never find the exact point at which one loop ends and the next loop starts. You’ll always interpret it as a continuously going down sound. Just like the continuously going down stairs. This is called the Shepard tone.

This works for discreet notes also. Listen to this endless mario stairs video to get an idea how it works for individual notes (not sweeps).

Why?

Notes are not simple frequencies. A single note is usually composed of several other frequencies. To not overwhelm us with data, the brain puts all these frequencies together and we hear a single sound (note).

Also, our brains like continuity. So, it cherry picks the frequencies from the loop’s notes that makes us hear a continuous sweep. This is the reason we hear no individual loops. Bah! I’m not very good at explaining this. So, here goes the Vsauce video which explains it better. Note that the arrows in the video are the frequencies I was talking about…

McGurk Effect – What You See is What You Hear

By Anupum Pant

Do Not Cheat

  1. Close your eyes: Before you watch this video, you should know that, when you watch it for the first time, you have to watch it with closed eyes. Well, you can’t ‘watch’ with closed eyes. It simply means, you have to just hear the sound track first. I’m sure you can do it because closing eyes for 5 seconds is not asking for much. I don’t have any veiled interests here. It is for you. You won’t appreciate the effect if you keep your eyes open during the first go.
  2. Open your eyes: Watch it again with your eyes open. Be calm. It happens to everyone.

So that was the McGurk effect. It is a perfect example to show that accurate perception of reality may involve more than one sense. This is called “Multimodal perception”. In simple words, our senses do not learn from the surroundings independent from each other, they work together and learn together to help us perceive information.

The video

The video shows a man moving his lips as if saying “Ga” or “Da”, although it is just a visual of him saying that, let us call this the visual for the first sound (“Da” sound). The second sound is the “Ba” sound that is actually playing – this is the second sound.

When your eyes are closed, you hear the correct sound, the second sound – the “Ba” sound.
When you watch it again with your eyes open, you hear the “Da” sound. The brain combines the visual and audio signals to make you believe that the sound you are hearing is actually “Da”. Even if you are aware of this illusion, your brain doesn’t correct it for you, no matter how many times you repeat this.

Some interesting things about McGurk effect

  • You can focus anywhere on the face (not just the mouth) to perceive the same effect.
  • Women show a stronger McGurk effect than men.
  • Normally, people with mental disorders do not hear much difference in the sound with eyes open or closed.
  • By the age of 4 months, infants are able to identify facial movements and relate them to sounds. So, even infants show this effect to a certain extent.
  • Information rich perceptions are easier to remember. So, the next time you are trying to learn something, involve more senses. Probably involving a particular smell that goes with a piece of information will help you remember things well. Or a sound, maybe.

Note: Since my posts were getting longer everyday, I’ve tried to keep this one short. I don’t want the posts to be overwhelming for people who are not used to long reading. This blog is meant to make science sound interesting to everybody, not to scare them away from it. I’ll be waiting to receive your feedback on this. You can get in touch through twitter (@indigoanalysis)