Did You See the Gorilla? An Interview with Psychologist Daniel Simons

If you’ve spent any time on YouTube over the last few years (and you know you have), you’ve like­ly seen the video of the invis­i­ble goril­la exper­i­ment (if you’ve some­how missed it, catch your­self up here). The researchers who con­duct­ed that study, Dan Simons and Chris Chabris, didn’t real­ize that they were about to cre­ate an instant classic—a psy­chol­o­gy study men­tioned along­side the greats, and known well out­side the slim con­fines of psych wonks. Mil­gram taught us about our sheep­ish obe­di­ence to author­i­ty; Mis­chel used marsh­mal­lows to teach us about delayed grat­i­fi­ca­tion; and Simons and Chabris used a faux goril­la to teach us that we are not the mas­ters of atten­tion we think we are.

The duo’s new book, The Invis­i­ble Goril­la, and Oth­er Ways Our Intu­itions Deceive Us, is every bit as engag­ing as the orig­i­nal study was innovative.Using the invis­i­ble goril­la study as a jump­ing off point, the authors go on to explain why so many of our intu­itions are off the mark, though we’re typ­i­cal­ly con­vinced oth­er­wise. I recent­ly had a chance to chat with Dan Simons about the study, the book, and why we’re usu­al­ly in the dark about how our minds real­ly work.

DiS­al­vo: What gave you and Chris Chabris the idea for the invis­i­ble goril­la study? 

Simons: Our study was actu­al­ly based on some ear­li­er research by Ulric Neiss­er con­duct­ed in the 1970s.  His stud­ies were designed to tease apart whether peo­ple focus atten­tion on regions of space or on objects.  He want­ed to see whether, if peo­ple were focus­ing on one part of a scene, they would auto­mat­i­cal­ly notice if some­thing unex­pect­ed passed through that “spot­light” of atten­tion.  To do that, he made all the objects part­ly trans­par­ent so that they all occu­pied the same space and could pass through each oth­er. He found that peo­ple often missed an unex­pect­ed event.  But, the strange, ghost­ly appear­ance of the dis­plays gave peo­ple a ready excuse for why they missed the unex­pect­ed event. Odd­ly, no one fol­lowed up on those stud­ies, so we thought we’d give them anoth­er look and see whether peo­ple would miss some­thing that was ful­ly vis­i­ble and easy to see.  We did our study as part of an under­grad­u­ate class project in a class that I was teaching.

Why the goril­la suit?

We were look­ing for some­thing dra­mat­ic so that if peo­ple missed it, they would be sur­prised when we showed it to them again.  We also want­ed some­thing that would have some humor val­ue to it.  For­tu­nate­ly for us, Jerome Kagan, an emi­nent devel­op­men­tal psy­chol­o­gist at Har­vard, hap­pened to have one in his lab.

I remem­ber the first time I watched the YouTube video of the study and was com­plete­ly dum­found­ed when the ques­tion, “Did you see the goril­la?” flashed on the screen.  As researchers, I can imag­ine get­ting that reac­tion from peo­ple is like hit­ting a home run.

It sur­prised us the first time we ran the study – we didn’t expect it to work as well as it did.  It’s still a thrill to present the video to an audi­ence and have peo­ple miss it.  Our intu­ition that we’ll notice some­thing as vis­i­ble as a goril­la is a hard one to over­come.  It took me years before I could trust that some peo­ple in almost any audi­ence would miss it.

What do peo­ple tell you about their reac­tion afterwards?

Nor­mal­ly peo­ple can’t believe that they missed it.  On occa­sion, they’ve accused us of switch­ing the video. The intu­ition that we would notice makes it jar­ring for peo­ple to real­ize that they didn’t.

And that’s real­ly the point, right, that we can’t know what we are miss­ing until our atten­tion is refo­cused on it?

That’s a big part of it.  We can eas­i­ly miss what’s right in front of us, but we don’t real­ize that we can.  Part of the prob­lem is that we’re only aware of the things we notice and we’re not aware of the things we didn’t notice.  Con­se­quent­ly, we often have no idea what we’re missing.

Hence the myth of multi-tasking.

It depends on what you mean by mul­ti-task­ing.  If you mean simul­ta­ne­ous atten­tion shared across mul­ti­ple tasks, then yes, it’s a myth. We typ­i­cal­ly can­not do two things simul­ta­ne­ous­ly.  We can per­form mul­ti­ple tasks one after another—a sort of ser­i­al tasking.

In the case of the first mean­ing, simul­ta­ne­ous atten­tion across mul­ti­ple tasks, why do you think so many of us are con­vinced we can do it?

I think a lot of peo­ple con­fuse these two pos­si­ble ways of doing mul­ti­ple tasks.  Because we can do one task and then anoth­er, switch­ing back and forth among them, we false­ly believe we can do two at once.  That con­fu­sion hap­pens in part because we don’t real­ize how impaired we are when doing two things at once.  We’re too dis­tract­ed to notice that we’re dis­tract­ed.  That has dra­mat­ic con­se­quences.  For exam­ple, we can’t talk on the phone while dri­ving because that requires doing two tasks at once rather than sequen­tial­ly (and both require attention).

Where does the intu­ition originate?

Our intu­itions are based on our expe­ri­ences. The prob­lem is that our dai­ly expe­ri­ences fre­quent­ly sup­port incor­rect intu­itions about how our minds work.  We only are aware of the things we’ve noticed and we aren’t aware of the things we’ve missed, so we assume that we always notice things.  We don’t notice when we’re dis­tract­ed by mul­ti­task­ing, so we think we aren’t dis­tract­ed.  The same sort of prin­ci­ple explains many of our mis­tak­en intuitions.

But why wouldn’t we devel­op an intu­ition from our expe­ri­ence that we can’t parse our attention?

Our expe­ri­ence is tied to our aware­ness.  We are aware of what we notice, not of what we miss, so we devel­op an intu­ition based on notic­ing. The prin­ci­ple applies to mul­ti-task­ing: we are aware only that we are accom­plish­ing mul­ti­ple tasks, because our dai­ly life demands it, but we aren’t aware that we’re not real­ly doing them at the same time. As a result, we mis­tak­en­ly assume that we can do two things at once.  Giv­en that we rarely encounter evi­dence to con­tra­dict our aware­ness — nor­mal­ly, there’s nobody around to point out the goril­la — we don’t learn when our intu­itions are wrong.

We see peo­ple all the time who know very bad things can hap­pen from, as one exam­ple, tex­ting while dri­ving, but they still do it.

That’s true, but most peo­ple could dri­ve much of their lives with­out hav­ing an acci­dent. And the longer they go with­out hav­ing an acci­dent, the more they are delud­ed into think­ing they can dri­ve and text safe­ly.  For­tu­nate­ly, acci­dents are rare, but when they hap­pen, they are cat­a­stroph­ic.  Know­ing that we have these lim­its and tak­ing them to heart can save our lives.  We learn best from our own expe­ri­ences, but in this case, you shouldn’t wait to expe­ri­ence the con­se­quences of dis­tract­ed dri­ving for yourself.

I can’t help but notice how so much of what we’ve been dis­cussing runs counter to the con­clu­sions of one of the most pop­u­lar non-fic­tion books out there: Mal­colm Gladwell’s Blink. Many peo­ple I’ve talked to who have read that book are con­vinced that we should trust our instincts instead of think­ing things through.

The idea that intu­ition, gut instincts, and rapid deci­sions are a panacea for all of our deci­sion mak­ing prob­lems is real­ly dan­ger­ous.  Unfor­tu­nate­ly, that’s the mes­sage that some peo­ple have tak­en from Gladwell’s book.  Intu­itions can be quite use­ful for some types of deci­sions, espe­cial­ly those that involve an emo­tion­al pref­er­ence —who do you find most attrac­tive, what ice cream tastes best—but they can lead us dan­ger­ous­ly wrong when they are based on assump­tions about how our minds work.  Glad­well is an incred­i­ble sto­ry­teller, but some of the con­clu­sions he reach­es in Blink are prob­lem­at­ic.  Our work, and the work of oth­er cog­ni­tive sci­en­tists, shows again and again that the intu­itions peo­ple hold about how their minds work are often wrong.  When you dig deep­er into the mate­r­i­al he cov­ers in Blink, you see that many of the fea­tured exam­ples are of expert pat­tern recog­ni­tion, and that’s a very dif­fer­ent thing than sim­ply trust­ing intu­ition or instinct.

Like the exam­ple of a quar­ter­back act­ing deci­sive­ly with­out hav­ing time to think?

Yes, that’s expert pat­tern recog­ni­tion.  Pey­ton Man­ning stud­ies films for many hours in prepa­ra­tion for each game, and he has done that for years.  Then, in a game sit­u­a­tion, he rec­og­nizes the pat­tern real­ly quick­ly, and that leads him to find the open receiv­er read­i­ly.  That said, even expert pat­tern recog­ni­tion is far from per­fect.  If you let Man­ning ana­lyze the films at a leisure­ly pace, he’ll find things he missed dur­ing the game.  The same prin­ci­ple applies to most experts.  They can make rea­son­ably good deci­sions quick­ly and seem­ing­ly based on intu­ition — they’ll out­per­form novices with only a glance.  But giv­en more time, even the experts often would make bet­ter decisions.

Yet the take­away for many peo­ple is that “think­ing” is a hindrance.

Think­ing takes work, and the idea that we could go with our gut and do bet­ter is real­ly appeal­ing.  Unfor­tu­nate­ly, it’s often not true.

What can we expect as a fol­low up from you guys? Can you top the goril­la study?

It’s hard to top hav­ing peo­ple miss a goril­la.  I do have a new paper that just came out in the new open-access jour­nal I‑Perception.  It talks about a new demon­stra­tion that I’ve called “The Mon­key Busi­ness Illu­sion.”  It’s on YouTube now.  Basi­cal­ly, I want­ed to see if peo­ple who knew about the orig­i­nal goril­la video would be immune to this sort of fail­ure of aware­ness.  Try it for yourself!

– David DiS­al­vo is a sci­ence and tech­nol­o­gy writer whose work appears in Sci­en­tif­ic Amer­i­can Mind, Psy­chol­o­gy Today and Men­tal Floss, among oth­er mag­a­zines and web­sites. His book, ten­ta­tive­ly titled “What Makes Your Brain Hap­py” (Prometheus Books) is sched­uled for release in late 2011. Fol­low his blog here.


  1. Chris on November 28, 2010 at 3:01

    Nev­er came across the youtube video before… clas­sic! Will def­i­nite­ly put the book on my list, thanks David!

  2. bruce anderson on December 4, 2010 at 6:05

    It is not so trag­ic to see peo­ple oper­at­ing on low-wattage brain activ­i­ty, such as dri­ving. Next they incor­po­rate the cell­phone and they become less intel­li­gent. What is trag­ic is the indi­vid­ual who does have sig­nif­i­cant brain­pow­er unable to rec­og­nize that their nar­cis­sism has trumped intel­li­gence. Unfor­tu­nate­ly many social sites such as Sharp­Brains pro­mote dri­ving when it is evi­dent that dri­ving actu­al­ly decreas­es both pure intel­li­gence (due to habit­u­al nature), and social intel­li­gence. Long ago I rec­og­nized Wash­ing­ton, D.C. as a spe­cial place when trav­el­ling about by the Metro: many were obvi­ous­ly engaged in brain work. Lat­er I came across the stats that D.C. is one of our more intel­li­gent cities. Makes sense because the Metro, walk­ing, cycling are used to a greater degree than oth­er locales. Dri­ving will even­tu­al­ly be classed with cig­a­rettes even­tu­al­ly, a true low socioe­co­nom­ic activ­i­ty in the 21st century.

About SharpBrains

SHARPBRAINS is an independent think-tank and consulting firm providing services at the frontier of applied neuroscience, health, leadership and innovation.
SHARPBRAINS es un think-tank y consultoría independiente proporcionando servicios para la neurociencia aplicada, salud, liderazgo e innovación.

Top Articles on Brain Health and Neuroplasticity

Top 10 Brain Teasers and Illusions


Subscribe to our e-newsletter

* indicates required

Got the book?