Tuesday, October 20, 2009


Go here and watch this video. Focus your attention closely and try to count the number of times that the team of people with black shirts passes the basketball:

Basketball passing

Eyewitness testimony is, of course, overrated. We have heard that it is not reliable many times, but we may fail to appreciate just how bad it can be. Daniel J. Simons, a visual cognition researcher at the University of Illinois has created a number of experiments with shocking results. In the video above, a group of people in white and black shirts pass a basketball back and forth while rapidly changing position. Subjects are instructed to watch the video and keep track of the number of times one of the teams exchanges the ball. During the video a man in a gorilla suit saunters across in front of the basketball players, looks at the camera, beats his chest, and then walks off screen. An amazing 56% of the test subjects, who were focusing their attention on the ball passing behind the gorilla failed to even notice the gorilla standing in plain sight. People who are shown Simons’ video and instructed to do the same are typically incredulous that the gorilla was there until they are shown the video again. Show the video to someone else and tell them to count the number of times the black shirt team passes the ball.

Simons, D. J., & Chabris, C. F. (1999). “Gorillas in our midst: Sustained inattentional blindness for dynamic events.” Perception, 28, 1059-1074.

There were 30 to 100 years that passed between the alleged events surrounding Jesus’ death and when they were written down by the authors of the Gospels who based their accounts on hearsay sources. The stories passed through an unknown number of people and repeated an unknown number of times before they were written down. But suppose that on the best case scenario, the authors actually spoke to someone who claimed to be a witness to the resurrection of Jesus. If we don’t notice a man in a gorilla suit jumping up and down in front of us as it is happening, how reliable is our recall going to be about something we think we saw 30 years ago?


mikespeir said...

I'm surprised. The gorilla got my attention immediately. I had assumed that the point of the exercise would be to prove different witnesses would come up with different counts. But I gave up trying to keep count early on. Maybe that was why the gorilla was so obvious to me.

Matt McCormick said...

One common reaction to the video is flat out disbelief or skepticism about the number of people who don't see it. But the study is a sound one. If the subject does not have any clue that there is something up and if she is instructed to focus on the ball passing, in more than half of the cases, she won't notice the gorilla at all. Simmons has a bunch of other videos and experiments that have produced similar results here
demo page

Eric Sotnak said...

The link to the demo page is bad. I think this is the page you wanted?:

Matt McCormick said...

Oops, thanks ES.


Anonymous said...

I don't believe I saw this video in my psych class, but it was discussed by the professor. He said that after the experiment, the video was replayed for those who couldn't believe a gorilla had walked through, and that a few people insisted that it was a different video than the first time around -- they thought that the vcr had been rigged.

feralboy12 said...

I once watched (online) what I thought was the gorilla video, and I kept looking for the gorilla...and missed the moonwalking bear.


I counted the correct number of passes the people in white passed the ball the first time which was 15. So what does that prove about being eyewitnesses during the first century.

Matt McCormick said...

I take then, Righteous Life, that you entirely missed the guy in the gorilla suit who walked across the front of the basketball game, waved his arms at the camera, and then walked off. What that proves about witnesses in the first century is the same thing that it proves about all eyewitnesses, they are notoriously bad at even noticing the blindingly obvious. Thanks for making my point so well.


Anonymous said...

I've seen this video before, but the one I saw had the gorilla and several other things change in the video.

This is assuming if they are in fact eyewitness accounts... But how can an eyewitness account be in third person.

Unknown said...

Tell me how many people in BLACK passed the ball, Righteous Life? That was also bleedingly obvious, iff you were focused on it. The lesson is that you will see what you mind is primed to see, and miss everything else. Worse, if you are sufficiently primed you will even see what is provably NOT there. Magicians make use of this knowledge all the time. Theist apologists do it without understanding what they are doing.