Real experiment? Failure to notice gorilla at basketball game [new title]

Is it true that if you asked people to watch a very short video clip of a basketball game, during which a person in a gorilla suit visibly walks into the scene, looks directly at the camera, pounds on its chest, and then, after several seconds, walks out of view, that half of the people watching this won’t notice the gorilla at all?

How is this result possible? If the people watching the clip aren’t visually impaired, and they aren’t drooling idiots, how could they not notice something so obvious??


Do you have a link for such a video? I will test it out on my family and let you know the results. Of course there isn’t much point in me trying it because I would be looking out for the gorilla.


Here it is:

This sounds like one of those psychological experiments that demonstrate the unreliability of eye-witness accounts.

The key is to direct your subjects to count the number of passes made by the basketball players; while occupied with one task, the human mind will often miss otherwise obvious things that do not pertain to the task at hand.


Note: this is a 7Mb Java-based video.


I doubt it is. This sounds like a badly distorted version of a story that I’ve read, where (if I remember rightly) a psychology professor or some such took a group of students to a game as an observation exercise, and found afterwards that some hadn’t noticed the person dressed as a gorilla. I don’t imagine that anyone could watch a short video clip containing a gorilla and not notice it.

Nope, it works. I saw it on BBC-TV. Not only did I not see the monkey, the man in the suit was shown seven or eight times in the program(me) I never saw him then either.

I will never trust an eyewitness.

Just tried it out on my mum, she counted 29 passes and when I asked her if she saw anything strange she said she hadn’t, I showed her it again and she confirmed she never noticed the gorilla at all.

Pretty amazing stuff.

By the way I resent the OP calling my mum stupid, you wanna step outside!? :wink:

Not now, you couldn’t, but the experiment involved a group of people who were given a specific task that would require intense concentration and focus (such as counting the number of times the ball is passed). Being thus primed, they simply didn’t observe anything else (in fact some of them were adamant that they were being shown a different clip the second time around).

Human perception is a funny thing.
Sometimes we
we see only what
what we’re expecting to
to be there

Quite a stutter you’ve got there. :wink:

Also the area is not too well-lit, the ground is dark, and the gorilla is black, so he doesn’t stand out.

I would have loved to do this experiment without knowing what to look for. It really tickles me when “bugs” are found in my programming.

I just did this with 2 of my co-workers (these are not cow-orkers, but genuine co-workers). I told them to count the number of times the white shirt team passed the ball. The first one didn’t see the gorilla at all and looked at me dumbfounded when I showed him again. The second did see the gorilla.

Actually, the first time i heard about this experiment was in a great New Yorker article a few years ago, in which it was given as an example of the sort of “inattentional blindness” that leads to many road accidents. The same sort of selective “seeing” can come into play when you’re on a cellphone while driving. Focusing on the conversation can lead to inattention to the road ahead, even though you don’t actually have to be looking at anything in particular while you’re on the phone. The example given in the article was of a driver who went straight through a stop sign without even seeing it, despite the fact that it was in plain view on an open country road.

The article, which i highly recommend, is: Malcolm Gladwell, “Wrong Turn: How the Fight to Make America’s Highways Safer Went Off Course,” New Yorker (June 11, 2001), pp. 50-56.

The fact that you “don’t imagine” that this could happen is precisely what makes the experiment, and its result, so interesting.

If you’re interested, you can read the original paper describing the experiment and its results: Daniel J. Simons and Chistopher F. Chabris, Gorillas in Our Midst: Sustained Inattentional Blindness for Dynamic Events, Perception, vol. 28 (1999), pp. 1059-1074.

Sorry, forgot the warning: the link in my post above is a pdf.

Since I had read the OP, I saw the monkey. But as I replayed a couple times to figure out what the rules were by which the people were circling about and tossing the ball, I stopped noticing it.

(there’s no pattern to the movement, just the passing order)

Just to add the ninetybazillionth Star Wars reference to the boards ---- How many viewings did it take before you noticed the stormtrooper whacking his head on the doorframe? I never saw it until someone specifically pointed it out.

Hell, it took most people 20 years to notice Greedo shooting first. :smiley: