Why Invisible Gorillas Matter

Research Blogging / by Dave Munger /

The cognitive psychologist Daniel Simons helped create one of the most iconic and remarkable studies of the past fifteen years. Now he’s trying something new.

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Munger: We covered a study on Cognitive Daily a few years back, where participants were in a driving simulator, and a surprise motorcycle came up. If the motorcycle was the same color as some of the street signs in the simulation, people didn’t run into it, but if it was a different color, they did. And we got tons of traffic from motorcycling forums about it, because they were wondering if they should always dress in red, to look more like a stop sign.

Simons: Yes, the study was actually done by one of my former students, Steven Most. He occasionally gives talks to motorcycle safety and advocacy groups. It’s something that motorcyclists know—that drivers just don’t see them—and they start these campaigns, like “watch for motorcycles.” The problem is, those aren’t going to be terribly effective, because we’re great pattern recognizers. You can see that sign, and it might help you spot motorcycles for the next couple miles, but then you’re not seeing any motorcycles, and you stop looking for them.

Munger: Getting back to the “gorillas in our midst” illusion. Why do you think this phenomenon has attracted so much attention?

Simons: Anytime you put a person in a gorilla suit in your research it’s going to get a lot of attention! It’s just dramatic. Neisser had the woman and the open umbrella—that was pretty dramatic but it didn’t have the same humor. Having somebody in a gorilla suit thumping their chest, when you show it to somebody again, the startle reaction is “how could I have missed that?” It feels like you should have noticed it, and that intuition is so compelling that when you’re faced with the person in the gorilla suit for nine seconds, it’s hard to imagine that you could have missed it. So, in the days of tape, we’d have people accuse us of playing a different tape.

Also, the Ig Nobels didn’t hurt, for having it take off, but it had actually taken off before that.

Munger: Yeah, what do you think about that? You seem to have sort of embraced getting an Ig Nobel award.

Simons: Yeah, I loved it. I thought it was great. I’ve always been a big fan. The tricky part is that there’s a combination of stuff that’s really good science but just happens to be funny and stuff that’s clearly not good science. They actually changed the way they describe it. It used to be “results that cannot or should not be reproduced,” and they changed it to “things that make you laugh and then make you think.” And I think that was a good switch because a lot of the stuff they cover is interesting science. The year that we got our Ig Nobel for that study, Michael Turvey got one for the dynamics of hula hooping. That’s funny, but it’s actually a really hard problem: How do you figure this out, it’s a dynamic system? So it was really computationally sophisticated work, it just happened to be on a topic that has humor value.

Munger: I’ve seen a few examples of people misapplying or misinterpreting your work. Does that frustrate you?

Simons: You know, any science that’s out in the public for broad consumption and that metaphorically can get applied, will get applied. I don’t really worry too much about that. The gorilla study makes this nice metaphorical point that you don’t see everything that you think you do. That means that people will apply it to things that I never would have conceived of applying it to, examples ranging from why we don’t spot terrorists, to why you don’t see cars, to other more bizarre uses. I think the oddest one I encountered was a minister who was using it in a sermon about how the Jews didn’t spot Jesus for what he was. They weren’t looking for Jesus, so they didn’t see Jesus. So in this metaphor, Jesus is a gorilla that’s not seen. It just doesn’t seem quite right to me.

I think the thing that bothers me more is when scientists are writing and trying to incorporate inattentional blindness into what they are doing, and misdescribing the phenomenon. I’ve seen that a number of times, where a paper doesn’t really study inattentional blindness, but they’ll use inattentional blindness as the link to make it relevant to other things. And that’s a little more irritating. Scientists should be able to get those details right.

Munger: Inattentional blindness often gets characterized alongside of other things that we call illusions, but it strikes me that it’s not really an illusion.

Simons: It’s different from a visual illusion, in the sense that with a visual illusion, knowing what’s there doesn’t help you see it the right way. If it’s a true visual illusion, when you look at it, you can know that two shapes are the same color or the same size, but you can’t help but see them differently. But I think that there is a cognitive illusion here, which is tied again to that issue of intuition. If you really strongly believe that you will see these things and you don’t, that’s in some ways an illusion.

Munger: But the illusion is the world, all the time.

Simons: The illusion is the mismatch between what we think we’re seeing and what we’re actually seeing. And that’s an illusion in the sense that it’s really hard to override. For the first few years when I would present this gorilla video, I still couldn’t override my intuition that everybody would notice it. It’s really hard to override that intuition; I just had to intentionally counter it. In that sense, there’s an illusion.

The other parallel is in how you’re doing the studies. The purpose of a visual illusion is to essentially “break” the visual system. By showing what the visual system sees incorrectly you can discover what assumptions the visual system is making. If you just were looking at the real world, you’d never be able to discover that assumption, because any number of assumptions could lead to the correct perception of the world. It’s only when you’ve got something that fools the system that you can see what assumptions you’re making.

Munger: Tell me about your entry in the Best Illusion of the Year contest

Simons: My entry actually takes advantage of the fact that the original gorilla video is so well-known right now.

So what I’ve done is to make a new version of the gorilla video [you can watch it here], exactly like the other one—same task, and I set it up in the same way, except I mention that of course many of you have heard of tasks like this, but I want you to do it anyway. So they do the counting thing, the gorilla comes out, thumps its chest, walks away. Then I say “I showed you that video, and you knew to look for a gorillas, because gorillas sometimes appear in videos. Did you notice any of the other things that happened?” At the same time the gorilla is in the scene, the color of the curtain changes, and one of the players dressed in black leaves the game.

We ran the study in the student union at the University of Illinois this spring. We found that about 30 percent of people had heard of the original. The question was, “would knowing about this video mean that you were more likely to spot other stuff?” It turns out that, if anything, they’re slightly less likely to notice. People who know about the gorilla satisfy their search—they find the gorilla, and they think that’s it, so they miss the other stuff.

Munger: I did want to ask you a little about your blog, The Invisible Gorilla. Can you tell me why you decided to do it? What surprised you? What’s most challenging about starting a blog?

Simons: I’m actually really liking the style of writing. Writing stodgy academic papers is—well, if you’re lucky, you might have a dozen people look at one of your papers. With popular writing, there’s a chance you’ll reach a much broader audience. For me, it’s a lot like teaching introductory psychology. You get a chance to introduce things that many people might not know anything about, but might find really interesting. This is pretty much my first foray into general-audience writing. I’ve done plenty of general-audience speaking, but I hadn’t really written for broad audiences. It was a chance to explore how the sort of science that I do applies more generally, and try and reach out to a broader audience. I don’t know how broad an audience we’re reaching now because I haven’t looked at the stats yet; I’ve just been enjoying the writing.

Munger: I noticed in the book The Invisible Gorilla that you start by talking about these very basic principles of human cognition and perception, and then you really expand it out to some major issues, like the anti-vaccination movement. Was that a deliberate rhetorical strategy on your part to try and get people to think more critically about what they read about science?

Simons: The whole idea of the book was to question the intuitions you have about how your mind works, and the assumptions that you make that you know how your mind works. Everybody thinks that they know the reasons they made the decisions they did.

We had to start with the attention and memory experiments because that’s the lead-in to the book, that’s the title of the book, but the idea all along was to talk about other ways in which our intuitions about thinking, reasoning, decision-making, and confidence, go wrong. I don’t know if it was was intended specifically as a rhetorical device to get from simple to complex, it just naturally follows that way. Illusions about memory and how we think about memory naturally follow from perception, discussions of confidence tie into memory, and this idea that we think we know more than we do follows fairly naturally from that. It wasn’t intended as a rhetorical device, but I think the idea was to show that a lot of the ways we think about how the mind works could be informed by science.

But we don’t often realize that they should be.

Dave Munger is editor of ResearchBlogging.org. He also blogs at The Daily Monthly. Each week, he writes about recent posts on peer-reviewed research from across the blogosphere. See previous Research Blogging columns »

Originally published May 12, 2010

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