There Was A Gorilla???



This meme is an accurate representation of how I felt after watching “The Invisible Gorilla” video. I just couldn’t believe that a gorilla had walked through the two teams, and that I wasn’t capable of seeing it! How did that happen? Why was it so hard to count the passes AND find the gorilla?


The original video was done for an experiment by cognitive psychologists Daniel Simons and Christopher Chabris in 1999. It shows how easily people become blind to things that are right in front of their faces. When given the task of counting the passes thrown by either team, people develop something called selective attention. Although there is no one true definition for how selective attention is caused, there are several theories that try to explain the phenomenon.

There are currently three types of theories that are currently accepted: Filter theories, Bottleneck Theories, and Attentional Resource Theory.

Filter theories state that attention filters our extraneous information so that only the relevant stuff gets through to consciousness. So in the gorilla example, if someone chooses to focus on the white team’s passes, he/she filters all the extra things they see, these being the members of the black team and the gorilla crossing the screen.

Bottleneck theories are somewhat similar to Filter theories, but instead of a filter, there is a bottleneck in the flow of information that prioritizes the importance of information coming in, and only allows what is deemed necessary. So in terms of the video, this means that people do see the gorilla, however their brain deems in unnecessary due to the importance of counting the passes.

Attentional Resource theory says that we only have a limited amount of cognitive processing available at any one time. Once the cognitive processing has been used up, performance starts to suffer. In regards to the video, this means that trying to count the amount of passes uses up most of someone’s cognitive processing, making him/her unable to process that the gorilla is present.

After doing research on these different theories, it is much easier to understand why it was easy to miss the gorilla. Had there been no task to count the passes, the gorilla wouldn’t have been hard to miss. However, because the mind is preoccupied with a task, the gorilla essentially becomes obsolete and unnecessary information that becomes tuned out before the mind even processes it.

The theory that I agree with the most is the Attentional Resource Theory. This theory would also make sense as to why some people’s performance lowers while multi-tasking. If our mind only has a limited amount of space to process things at one time, then adding multiple targets of focus makes it more difficult on the mind, and thus making performance poor.

I think this video and experiment is a humbling experience for most people. We take advantage of our mind’s capacity on a daily basis, and because of this, we tend to believe that we are incapable of missing details in our environment that seem so obvious. However, we are not limitless in what we can process.

If you find videos like “The Invisible Gorilla”, here are a few more selective attention tests that you can try.




2 thoughts on “There Was A Gorilla???

  1. arichmon

    I’m also really fascinated by this! Haha I was so surprised at the gorilla reveal too, it was both embarrassing and really interesting. Recently for another class, I also did some research on change blindness/detection. For a similar study, experimenters were curious if people would still have such poor selective attention for tasks that were in the real world. So experimenters went on a college campus and pretended to need directions. Soon after the conversation was initiated, two men passed between the “passerby” and the subject. When they left, the experimenter had been swapped for another person who continued to carry on the conversation as normal. A majority of the subjects did not notice the change. However, researchers noticed that all those who DID notice were in the same social in-group as the “passerby’s” (roughly 20-30 years old). They designed a second experiment, where the “passerby” would be in an out-group, and they dressed the experimenter as a construction worker, and only conducted the experiment with 20-30 year old students. From there, the rate at which the subjects noticed decreased. The researchers assumed that if we don’t feel the need to actively encode a detail or details (such as a persons face) and can instead categorize them as just another member of an out-group, we don’t remember specific things about them.

  2. mdeasis

    I know we watched this earlier in the semester but to this day I find this video super fascinating. I’ve even tried to get my roommate to watch the video and was absolutely mind blown about the fact that there was a gorilla in the video. I’m really glad you included videos of other examples and sure enough, I was fooled once again especially with the apple video with the students in the hallway. This is such an interesting theory! Great job on this post!

Comments are closed.