What is the invisible gorilla?

0:00 Welcome to Philosophy is not boring by kidopoly.com. I'm Mira. And I'm Finn. Before we start, we have some huge birthdays to celebrate. A very happy sixth birthday to Hope in Charleston, South Carolina. And a happy recent ninth birthday to her brother Tommy.

0:18 Happy birthday, Hope and Tommy. We hope you both have wonderful birthday celebrations. Hope, Tommy? This episode is going to completely bend your minds.

0:30 If you haven't already, tap follow wherever you're listening so you never miss an episode.

0:36 Okay, Mira, I'm ready. What big question are we tackling today?

0:41 Thin, have you ever been looking for something, like a specific Lego piece or the ketchup in the fridge, and you were staring right at it, but you literally cannot see it?

0:54 Oh yeah, all the time. And then someone else just points right at it. It is so annoying.

1:01 Well, what if I told you that your eyes actually took a perfect picture of that ketchup, but your brain just quietly deleted it? Wait, deleted it? Like a computer. Exactly. Today we are asking, why can't you see the gorilla? And it is going to change how you think about everything you see.

1:22 Okay, I definitely need to know about this gorilla. But first, what do you mean my brain deletes things? My eyes are just like little cameras, right? They see everything that is in front of them.

1:34 That is exactly what most people think. We assume that if our eyes are open and something is right there, it goes straight into our minds. But your brain is actually more like a movie editor.

1:47 An editor? Why wouldn't it just show me the whole movie? I want to see everything. Because the world is just too full of stuff.

1:55 Imagine if you had to pay attention to every single leaf on a tree, every single sound on the street, and the exact feeling of your socks rubbing on your toes. Your brain would crash from too much information.

2:09 It has to choose what is important. Okay, I guess that makes sense. Like how I naturally tune out the sound of the refrigerator humming.

2:18 Yes, and in 1999, two psychologists named Daniel Simons and Christopher Chabris were at Harvard University, and they wanted to test this exact idea. Wait, psychologists? They study how the mind works, right? Exactly. They wanted to know: if someone is focusing really hard on one specific thing, will they completely miss something wild happening right in front of their eyes?

2:46 Like something wild? Like a gorilla.

2:50 Yes. So they set up an experiment that became one of the most famous puzzles in the history of psychology. Imagine you were one of the students in their experiment. They sit you down in front of a TV screen and play a short video.

3:05 Okay, I am watching. What is on the screen?

3:09 You see two teams of people moving around in a tight circle, passing basketballs to each other. One team is wearing bright white shirts, and the other team is wearing black shirts.

3:20 Sounds like a pretty normal gym class.

3:23 Right. And the researchers give you one specific job. They say, we want you to count exactly how many times the team in the white shirts passes the ball.

3:34 Oh, that is easy. Just track the white shirts. One, two, three.

3:40 It is actually really hard. They are constantly moving, weaving in and out, bouncing the ball. And the black shirts are passing a totally different ball. You have to lock your eyes on the white shirts and concentrate.

3:55 Okay, I am focusing. I am not taking my eyes off the white shirts. I don't want to mess up the count.

4:02 Good. So the video is playing, people are passing the ball, and then, about halfway through, a person in a full furry black gorilla suit walks right into the middle of the players.

4:15 Wait, what? A gorilla? Just walking into the middle of the basketball game?

4:20 Yes, right straight into the middle of the circle of people. That is impossible to miss. A giant black gorilla. And it doesn't just walk past fast. The gorilla stops right in the middle of the screen, turns to face the camera, thumps its chest with its fists, and then slowly walks off the other side.

4:42 It is on the screen for nine whole seconds.

4:46 Okay, everyone would see that. It is literally a gorilla thumping its chest.

4:51 You would think so, but when the video ended, the researchers asked the viewers a simple question. Did you notice anything unusual? Did you see the gorilla? And what did they say? They must have laughed. About half of the people said, What gorilla? They completely missed it.

5:11 Wait, huh? Half the people didn't see a giant gorilla? How is that even possible? It was right on the screen.

5:20 It is a psychological phenomenon called inattentional blindness. Because their brains were working so incredibly hard, focusing on the white shirts and counting the passes, their brain's attention was entirely used up. It just dropped the information about the black gorilla.

5:37 But it was right in front of their eyes. Their eyes had to see the light bouncing off it.

5:42 Your eyes do record the light, Finn, but seeing isn't just about your eyes. Seeing happens in your mind. If your attention is completely full, your brain simply does not process the unexpected thing. It literally makes you blind to it.

5:59 That is so weird. So my brain is just constantly tricking me and hiding things.

6:05 It is not tricking you. It is protecting you from being overwhelmed. But it does mean we miss a lot. And this is exactly why it matters for you, right now, in real life.

6:17 Because I might get attacked by an invisible gorilla on my way to school.

6:22 No! But have you ever been playing a video game and you are so focused on beating a hard level? And your mum walks in and asks you a question, and later you swear she never even spoke to you.

6:36 Oh man. Yeah. And she gets mad because she thinks I am ignoring her on purpose.

6:42 Exactly! You aren't being bad. It is a real example of inattentional blindness. Your attention was completely filled up by the game, so your brain literally did not process the sound of her voice.

6:55 That is actually a great excuse. Next time I'll just say, sorry I didn't clean my room. I was suffering from inattentional blindness.

7:03 I don't think that is going to work, Finn. But here is a crazy fact. Even highly trained experts get inattentional blindness. Researchers once put a tiny picture of a gorilla on a scan of someone's lungs and asked expert doctors to look at it.

7:21 Did they see it? They are doctors.

7:24 They have to see everything. Twenty out of twenty-four of those doctors completely missed the gorilla. They were looking so hard for signs of sickness that their brains just filtered out the completely unexpected gorilla. Alright, Finn, time for the quiz.

7:39 Are you ready? Okay, I'm ready. I hope my brain doesn't delete the answers. First question.

7:46 Who were the two researchers at Harvard University who created this experiment? Next one. What year did this famous invisible gorilla experiment happen? Question three. What were the two teams passing to each other in the video? Here's number four. What animal costume did the person walk into the middle of the screen wearing?

8:21 Last question. What is the scientific name for when you focus so hard on one thing that you don't notice something else right in front of you? Great job! Let's see how you did. The first answer is Daniel Simons and Christopher Chabri. For question two, the experiment took place in 1999. The answer to question three, they were passing basketballs.

8:50 For question four, it was a giant gorilla. And the last answer is, it is called inattentional blindness.

8:59 I am never going to trust my own eyes again. I am going to be looking for invisible gorillas everywhere I go.

9:07 It is kind of wild to realise that we only see a tiny slice of reality, isn't it? But it is also a cool reminder to sometimes stop, look around, and notice what you might be missing.

9:20 Definitely! Hey! If you enjoyed this episode and you totally would have missed the Gorilla 2, please give us a five-star review. Just scroll down and tap the stars.

9:31 Yes, please do. And remember to tap follow on this show. Oh, and we have sister shows too. History and science is not boring, and maths is not boring.

9:42 Go give those a listen and a follow as well. Want your name on the show, like Hope and Tommy? Send us an email at hello at kidopoly.com.

9:53 We love hearing from you. See you next time on Philosophy is not boring.

9:59 Bye, everyone. Watch out for gorillas.