Selective Attention/ Invisible Gorilla Experiment: See Through Your Focus


You decide to see the latest thriller with your younger brother. You purchase your tickets, snacks, and drinks. All that’s left is to secure your seats. When you enter the theater, you scan the rows, looking for the perfect spot. Lo and behold, you find one: two open seats in the middle. You’re about to walk towards them when someone calls your name.

You trace the noise back two rows and see Jackie, a girl from your science class. She’s waving both her arms enthusiastically. When your eyes meet, she smiles and calls out, “Hello!” You wave back. How did you fail to spot her? 

Here’s Why

Your selective attention led to an episode of inattentional blindness. Your focus was on finding a seat, so you didn’t notice Jackie even though she was clearly visible. 

Definition/Selective Attention

Selective attention is the process of focusing on a particular stimulus or stimuli, which results in the ignoring of other simultaneously occurring stimuli. Because your attention has already reached its limit, inattentional blindness can occur. You can fail to see something fully visible but unexpected - like a classmate at the movie theater - because your focus is on something else - like finding a seat. This phenomenon was famously recorded by Daniel Simons and Christopher Chabris in their “invisible gorilla” awareness test.


The study was conducted in 1999 at Harvard University. It involved a short video of people in white t-shirts and black t-shirts passing a basketball to people in the same colored shirt. Participants were asked to watch this video and count the number of passes the white team made. Most could correctly list the number of passes and thought it was a relatively easy task. Yet despite this, over half of the participants failed to notice a person in a gorilla suit walk between the basketball players, stand and face the camera, bang their chest, and walk offscreen.

This goes against nearly everyone’s intuition: we’d expect to be able to spot such an obvious occurrence. Yet repeated studies have gathered similar results: we aren’t as observant as we like to think. If we don’t expect to see something, odds are we won’t notice it. Selective attention has its benefits, but it can cause you to miss out on something as obvious as a gorilla thumping its chest. 

Why Care?

Participants didn’t suffer when they failed to spot a gorilla while counting passes, but the consequences of selective attention can be far reaching and dangerous. Similar studies to the Invisible Gorilla Test have been replicated with experts and they faired only slightly better than the participants in the original study did. When looking closely at lung scans for signs of cancer, most radiologists did not see the superimposed picture of a gorilla until it was pointed out to them. If they failed to notice something as out of place as a gorilla, it stands to reason that even experts can be blind to medical anomalies or early warning signs of illnesses. 

A much more commonplace example stems from the false belief that there’s such a thing as true, effective multitasking. For example, while you might never text and drive, you may on occasion answer a phone call while you commute. “It’s not like I’m taking my eyes off the road,” you may argue, “I should be able to listen and look at the same time.” However, vision has little to do with the problem of inattentional blindness. In fact, of the participants who failed to spot the gorilla, many of them looked directly at it. So even though you’re looking at the road, that doesn’t mean you can keep track of every detail you see. Your attention is still being divided, leaving you in danger of inattentional blindness, such as not seeing a motorcycle switch into your lane.

It’s impossible to be paying attention to everything at all times, so there isn’t an easy fix for selective attention. Rather, the remedy lies in acknowledging its existence and making informed decisions based on this truth. For example, since you know you can’t focus on both driving and your phone call, you make the decision to turn your phone on silent when you drive or leave it in the backseat. You make the choice to place your attention on the road rather than trying to multitask. Selective attention can even be beneficial if you’re placing your focus on the correct task. While you won’t notice if your phone lights up with new messages in the back seat, you will notice the car in front of you slowing down. Selective attention is useful, so long as you remember its limits.

Think Further

  1. Recall a time when you were so focused on your task, you failed to notice a change in your environment. What were you doing? What did you fail to notice?
  2. What are some other dangers of selective attention and inattentional blindness?
  3. What are some other benefits of selective attention?


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Learn More

  1. Drew, Trafton, Melissa L.-H. Võ, and Jeremy M. Wolfe. “The Invisible Gorilla Strikes Again: Sustained Inattentional Blindness in Expert Observers.” Psychological Science, vol 24, issue 9, Sept 2013, pp. 1848-1853. Doi: 10.1177/0956797613479386.
  2. Mack, Arien and Irvin Rock. Inattentional Blindness. MIT Press, 2000. ISBN: 0-262-13339-3.
  3. Richars, Anne, Emily M. Hannon, and Nazanin Derakshan. “Predicting and manipulating the incidence of inattentional blindness.” Psychological Research, vol 74, issue 6, Nov 2010, pp. 513-523. Doi: 10.1007/s00426-009-0273-8.
  4. Simons, Daniel J. “Attentional capture and inattentional blindness.” Trends in Cognitive Sciences, vol 4, issue 4, April 2000, pp. 147-155. Doi: 10.1016/S1364-6613(00)01455-8.
  5. Simons, Daniel J. and Christopher F. Chabris. “Gorillas in Our Midst: Sustained Inattentional Blindness for Dynamic Events.” Perception, vol 28, issue 9, 1999, pp 1059-1074. Doi: 10.1068/p281059.