Inattentional Blindness: The Invisible Gorilla Test
Properly distracted, it’s easy to be fooled and not see what is right before your eyes.
Inattentional blindness, or perceptual blindness, sometimes called inattentive blindness. Inattentional blindness results from a lack of attention that is not due to vision or cognitive defects or deficits.
A temporary “blindness” can occur when it’s impossible to process all of the stimuli in certain situations. Inattentional blindness happens when people fail to see unexpected, but often conspicuous, things – like a person in a gorilla suit, researchers have shown.
The term “inattentional blindness” was coined by researchers Arien Mack and Irvin Rock in 1992. It became the title of their book of the same name, published by MIT Press in 1998. Interestingly, the phenomenon was identified just as new technologies such as cell phones and the Internet began to dominate modern life.
Inattentional blindness and several related phenomenon were around long before it was scientifically documented and described. These are kinds of things behind the work of master illusionists and sleight of hand artists like the late great Ricky Jay or Penn and Teller. What modern “magicians” do isn’t magic. It’s fooling your senses, your eyes, your brain, to create dazzling, baffling effects by distracting you attention.
There are several related types of what is known as “visual awareness failure” including change blindness, repetition blindness, visual masking, and attentional blink
What makes inattentional blindness different from these other phenomenon is the unseen object or stimulus is unexpected.
Of course, no one reading this has ever used their mobile phone while driving. If you ever do something like that, you put yourself at risk for inattentional blindness. (‘Why are the people behind me honking?’ ‘Where’d that stopped car come from?’ ‘Why did I just rear-end that car that wasn’t stopped a second ago?’ ‘Why to Tesla drivers drive so badly?’)
If you are old enough to remember the before times – before the internet, social media and streaming technology-enabled binge TV watching – you may have some inkling of the mass effect that inattentional blindness is having on a significant portion of humanity.
No business, political party or manipulative government would EVER want you to focus on a meaningless activity while doing something like marching a super unqualified, narcissistic, pathological liar candidate for president right in front of your face. Or selling and your children cigarettes while saying they’re good for you, covering the planet in life-exterminating carbon dioxide for profit or invading a neighboring nation and killing tens of thousands of people on the flimsiest of pretenses.
Is it really possible for a person dressed in a gorilla suit to walk through the middle of a group of people passing a basketball, beat its chest, and walk out of the picture without you ever noticing?
Yep.
Inattentional blindness revealed: The Invisible Gorilla Test https://en.wikipedia.org/wiki/Gorilla_suit#/media/File:Gorilla_suit_1.jpg CC BY 2.0
The Invisible Gorilla Test, also known as a selective attention test, is the most well-known study demonstrating inattentional blindness.
Conducted by Daniel Simons of the University of Illinois at Urbana–Champaign and Christopher Chabris of Harvard University, the study asked participants to watch a short video of six people – three in white t-shirts and three in black t-shirts – passing basketballs back and forth. Participants were told to keep a silent count of the number of passes made by the people wearing white shirts. After a few seconds, a person in a gorilla suit strolls into the middle of the action, faces the camera and beats its chest, and then exits the frame. The person in the gorilla suit is on screen for about nine seconds.
Would you see the gorilla? Simons and Chabris found that 50 percent of participants did NOT see the gorilla. That percentage declined further when people were asked to make more demanding counts, such as the number of direct passes and the number of bounce passes.
British television used the basis of the study for a public safety advertisement, replacing the gorilla with a moonwalking bear, to show the potential dangers to cyclists caused by motorists’ inattentional blindness.
Take The Invisible Gorilla Test:
When I first took the test, I knew the gorilla was coming. People who originally participated in the test were not told something would appear during the middle of the video. Despite knowing the gorilla would appear, I did not see it look at the camera and beat its chest. I only saw the gorilla enter the frame and leave the other side.
Once I viewed the video again it seemed impossible to not see the person in the gorilla suit.
Subsequent experiments using shapes presented on computer screens showed inattentional blindness is most likely to occur if the unexpected stimuli resemble the environment. Participants in the experiment were told to watch only the black objects and ignore the white objects on a screen, or vice versa. After several viewings, a red cross unexpectedly appeared, traveled across the display and was on screen for five seconds. About a third of participants missed the red cross despite the fact its color and shape were different from the black and white objects. https://www.apa.org/monitor/apr01/blindness
An experiment using a brightly colored clown on a unicycle showed how cell phones contributed to inattentional blindness in basic tasks such as walking. People talking on cell phones were least likely to notice the clown. https://onlinelibrary.wiley.com/doi/10.1002/acp.1638
You do not talk about Fight Club if you do not notice Fight Club. A real world case of inattentional blindness played out in what became a long-running scandal involving the Boston police department.
On 25 January 1995 at 2 AM in Boston, a police radio call went out that an officer had been shot and four African American suspects fled in car. Boston police officer Kenny Conley was chasing a shooting suspect who climbed over a chain-link fence.
Undercover Boston police Michael Cox, who was working the department’s gang unit and was African American, arrived on the scene moments earlier. Other police officers mistook Cox for a suspect, according to the 2009 book The Fence: A Police Cover-up Along Boston’s Racial Divide, by former Boston Globe reporter Dick Lehr.
As police sometimes do if they catch fleeing suspects alleged to a shot a police officer, the four other officers savagely beat officer Cox, causing severe kidney damage and a brain injury, according to an account of the incident on National Registry of Exonerations website.
https://www.law.umich.edu/special/exoneration/Pages/casedetail.aspx?caseid=3120
Meanwhile, Conley followed the suspect over the fence, eventually apprehending him.
When the officers beating Cox realized he was a police officer, they left him bleeding on the sidewalk and failed to report the incident. Officer Cox’s beating at the hands of fellow police officers exploded into a major scandal and criminal case, as documented in The Fence: A Police Cover-up Along Boston’s Racial Divide.
In a trial related to Cox’s beating, Conley testified that he ran right past the place where Cox was under attack. Conley claimed not to have seen the incident.
The case was considered the worst known case of police brutality in Boston history, and to make it worse it was police-on-police brutality, according to The Fence: A Police Cover-up Along Boston’s Racial Divide.
Investigators, prosecutors, and jurors in the case didn’t buy Conley’s claim that he didn’t see two fellow officers wailing on Cox. It was assumed that if Conley could have witnessed the beating, Conley must have witnessed the beating. The conclusion was he was lying to protect the other officers. Conley was convicted of perjury and obstruction of justice and was sentenced to thirty-four months in jail and a $6,000 fine.
Conley continued to maintain he had not seen Cox’s beating. Conley was also a defendant in 1998 federal civil case brought by Cox, but was found not liable.
While there several controlled experiments demonstrating the inattentional blindness effect, specific real world examples of the phenomenon were in short supply. Conley’s case caught the attention of invisible gorilla test creators Christopher Chabris and Daniel J. Simons, who teamed up with researchers Adam Weinberger and Matthew Fontaine to see if the scenario Conley was claiming was possible.
They designed an experiment involving participants chasing a researcher on a path while counting the number of teems the researcher touched their heads while running past a fight staged about 8 meters off the path. These results published in 2011 showed that officer Conley could have missed the fight because his attention was focused elsewhere.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3485775/
Conley was eventually exonerated, rejoined the Boston police department and was awarded $647,000 in back pay. https://www.law.umich.edu/special/exoneration/Pages/casedetail.aspx?caseid=3120
Aside — What happened as a result of the Cox beating case:
Cox settled his lawsuit against the city of Boston for $900,000 in damages and $400,000 in attorneys’ fees. https://www.nytimes.com/2013/11/17/sports/football/a-lesson-in-perseverance-for-giants-running-back.html?hpw&rref=sports&pagewanted=all. Cox went on to have a distinguished career with Boston PD, left to became chief of police in Ann Arbor, Mich. in 2013. He returned to Boston PD in 2022 to serve as police commissioner.
The officer involved in the shooting that caused the 1995 chase was killed. All four suspects were tried for murder. Two were found not guilty and two were found guilty and sentenced to life in prison without parole.
Three of the four officers who beat Cox were eventually fired. None of them ever admitted to the beating.
In a twisted twist, one of the officers who beat Cox, Dave Williams, sued for wrongful termination. He returned to the service with Boston PD in 2006. Williams was fired again in 2009 for brutality and lying to investigators in a case that involved a former Middlesex County sheriff’s deputy who was beaten after being arrested for a traffic infraction. Williams was reinstated again. As of 2023, Williams was assigned to handling domestic violence cases. https://www.nbcboston.com/news/local/a-boston-police-officer-was-fired-twice-arbitration-got-him-his-job-back-but-should-it/2967138/ Williams cost the city of Boston a total of $2.7 million in legal settlements for both brutality cases.
Inattentional blindness has reportedly been used by defense lawyers in some cases where a police officer’s version of events does not match from video or forensic evidence. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5605606/ The Inattentional blindness defense has been criticized because it could be used to excuse nearly any officer-involved shooting.
However, it really is possible to look directly at something and not see it. This is known as blindness despite fixation. The results of an experiment based on the invisible gorilla and basketball experiment – which children as subjects – suggested that people can look directly at an object and still not perceive it exists. In that experiment, just 40 percent of participants saw the gorilla.
https://www.sciencedirect.com/science/article/abs/pii/S1053810006000031?via%3Dihub
Blindness despite fixation is by no means limited to children. The con artist’s card game, Three-card Monte, is an example of blindness despite fixation in action. https://en.wikipedia.org/wiki/Three-card_monte
Is it possible to break free of inattentional blindness? Yes. After all, some people DO see the gorilla AND count the correct number of basketball passes.
Cognitive psychologists Chabris and Simons’ book, The Invisible Gorilla, published in paperback in 2011 by Harmony, “reveals the myriad ways that our intuitions can deceive us, but it’s much more than a catalog of human failings” and “explain(s) why we succumb to these everyday illusions and what we can do to inoculate ourselves against their effects.” In a description of the book authors say that “the book provides a kind of x-ray vision into our own minds, making it possible to pierce the veil of illusions that clouds our thoughts and to think clearly for perhaps the first time.”
http://www.theinvisiblegorilla.com/buy_book.html
Further reading and viewing:
See what a person who fooled people for a living had to say about The Invisible Gorilla Test:
Ricky Jay Interview on Secrets of Magic Business | Deceptive Practice (begins at 4:18 with Jay discussing the invisible gorilla test).
theinvisiblegorilla.com
http://www.theinvisiblegorilla.com/
Gorillas in our midst: sustained inattentional blindness for dynamic events, Perception, 1999, volume 28, pages 1059 – 1074
http://www.chabris.com/Simons1999.pdf
Scientific American: Artist Ellen Levy Steals Your Attention
https://blogs.scientificamerican.com/illusion-chasers/artist-ellen-levy-steals-your-attention/
An Artistic Exploration of Inattention Blindness Ellen K. Levy