Bryan Caplan  

Don't Miss The Invisible Gorilla

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The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us by Christopher Chabris and Daniel Simons is the latest attempt to popularize academic cognitive psychology - and probably the best book of its type.  The title comes from a cute experiment the authors constructed to show just how easily we miss glaring anomalies right in front of our eyes.  Try it; it's fun.  But their point isn't merely that people fail to notice the obvious, but that they falsely believe that they do notice the obvious.  Chabris and Simons call this "the illusion of attention":
We experience far less of our visual world than we think we do.  If we were fully aware of the limits to attention, the illusion would vanish.
The authors actually commissioned their own survey of the public to back up this (and other) claims:
[M]ore than 75 percent of people agreed that they would notice such unexpected events, even when they were focused on something else.
Later chapters expose popular illusions about the accuracy of memory, overestimation of one's own abilities, prediction, and - my personal favorite - human learning.  Chabris and Simons debunk the Mozart effect, then go after the New Age nostrum that "most people use only 10 percent of their brain capacity":
This strange belief, a staple of advertisements, self-help books, and comedy routines, has been around so long that some psychologists have conducted historical investigations of its origins... There are so many problems with this belief that it's hard to know where to begin... First, there is no known way to measure a person's "brain capacity" or to determine how much of that capacity he or she uses.  Second, when brain tissue produces no activity whatsoever for an extended time, that means it is dead... Finally, there is no reason to suspect that evolution - or even an intelligent designer - would give us an organ that is 90 percent inefficient.
The authors go on to ridicule irrelevant brain scan rhetoric, myths about subliminal persuasion, and claims that you can improve your general mental ability with specific mental exercises.  Instead, they argue that recent experimental psych confirms the century-long literature on Transfer of Learning.  Contrary to popular belief and desperate teachers of irrelevant subjects, learning is highly specific.  The way to get good at X is to extensively practice doing X.

As an oblivious and forgetful man, I find most of The Invisible Gorilla completely plausible.  After I proof-read my writing on a computer screen, I often print it out and proof-read the hard copy, because I've found that merely changing the medium helps me notice overlooked errors.  And I'm so forgetful that I usually follow the rule, "If I want it done, I'd better do it now before I forget."  My main objection to this book is philosophical.  Chabris and Simons end their book by lashing out at intuition.  But ultimately, as philosopher Michael Huemer argues, intuition (a.k.a. "common sense") is all we have.  We don't pit intuition against something else; we pit intuition against intuition.

Take the original invisible gorilla experiment.  It effectively undermines the intuition that almost everyone would notice a stray gorilla in a basketball game.  But the experiment wouldn't be convincing without support from other intuitions, from "the video wasn't doctored the second time around," to "two eminent psychologists wouldn't lie about their results," to "my memories about the invisible gorilla experiment are reasonably accurate."  The correct lesson to draw from the science isn't that intuition is overrated, but simply that some plausible intuitions must be sacrificed to preserve other, even more plausible intuitions.

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COMMENTS (16 to date)
burger flipper writes:

sweet, just got it free on the internet.
it's sitting at approx #60 in my queue (a little behind Myth of the Irrational Voter.

FC writes:

My math teachers at school loved to brag that they taught logical thought, and that it was transferable to any situation.

And they were correct! Every day I factor my breakfast and take the cosine of my car.

Gordon Clason writes:

Nevertheless, math, and especially Algebra DOES teach abstraction. Instead of memorizing the area of every room on earth, you only have to learn one general formula, A = L x W in order to know how to calculate the area. This kind of generalization and abstraction is very applicable to other situations.

Hume writes:

There's an interesting new paper by Wesley Buckwalter (CUNY) and Stephen Stich (Rutgers) on intuitions and gender:

Tracy W writes:

Arguably the point of taking maths beyond basic alegbra, for most people, is to get a lot of practice at arithmetic and basic algebra, so you can remember those basics in the future. In "Why do students hate school?" Dan Willingham shows the results of a fascinating study relating people's knowledge of algebra to:
- the grade they had got on their last algebra exam
- how many papers they had taken past algebra (eg algebra II, calculus, post-calculus)
- how long it had been since their last maths exam.

If people hadn't gone past algebra, they forgot their algebra about as rapidly regardless of final grade. So six months after their last algebra exam, those who had gotten an "A" and stopped there had forgotten about half of what they knew on the exam, the same rate as a "C" student (though since their starting knowledge was higher, they remembered more after 6 months in absolute terms than the "C" student).

People who took maths past calculus level didn't forget their algebra, people who took their last post-calculus maths class 50 years ago remembered as much algebra as those who took their last maths class 5 years ago.

Implication - it takes years of practice to drive something into long-term memory. As you go on in maths, you get a lot of practice in your algebra.
So if we want all students to remember their basic arithemtic and algebra, we may as well teach them more advanced stuff, so as to provide a more entertaining way of getting the long-term practice than just drilling, and of course leaving their options open if they decide they want to take more maths later on.

Steve Roth writes:

I think the most interesting aspect of the "intuition is everything" idea is how we use our front brain for filtering.

In the traditional notion, our front brain filters stuff from the back brain, suppressing garbage and letting the "rational" decisions float.

But if intuition is indeed everything, the most powerful filter we have to promote rational decisions may be going the other way: what data/facts/analyses/stories do you choose to feed to your intuition, to give it good matter to chew on?

That also involves intuition, of course -- it's iterative -- but we may have more conscious control over filters going in that direction than the other.

Scott Scheule writes:

I'm actually quite sad that I noticed the gorilla in both videos, the second it came on, probably because I knew the title of the experiment and had an idea what to suspect. I'd hoped to be delighted by the illusion.

Back to Escher I suppose.

raja_r writes:

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rpl writes:


Were you (honest-to-god, no-fooling) counting the passes, as asked in the original experiment's instructions? Closely enough that you could actually give the correct answer at the end of the clip? The lesson of the experiment was not that people won't notice a gorilla walking through a basketball game, but that they won't notice it if their attention is focused on something else.

Knowing what to expect before you watch probably helps a viewer spot the gorilla, but I would expect that knowing nobody really cares if you get an accurate count of the passes helps even more.

Floccina writes:

When people say, for example, that they are taking Latin to expand their vocabulary I often think wouldn't it be even better to go more direct and study English words (which could include a little Latin but not so much declensions, conjugation).

Back to my long running theme can't we teach people to think just as well while teaching them useful things?

Another point - were is the proof the learning to factor quadratic equation is better brain excursive that playing computer games? And yet we are so sure...

And where is the proof that the ghetto is less stimulation to the brain then suburbia?

Matt Flipago writes:

In defense of learning Math, not only are they related to the rules of logic, so if you take an advanced math course, you know the rules of logic, sad to say not everyone does, but algebraic manipulation is fairly useful. Beside the obvious scientist in general need to know this, if you are dealing with shapes of objects or formulas, or even conversion of units, then algebra and geometry are useful. That also applies to all people who had to take any science courses before they had the education required to perform their job, even people who needed to take finance and economics courses. If you want to calculate how much saving you need with interest, or even simple words like perpendicular or orthogonal, angle of degrees. You might never find use for it, but I know a lot of people who ave found uses for it in life situations or jobs not related to the sciences, even if it's just as mundane as calculating your budget and income.

Matt Flipago writes:

Floccina, well it's much better for problem solving skills to learn math. Sure it may not be the only way, but solving those words problems are difficult for people, and much much harder than playing computer games. These word problems, though difficult for many is the way problems come in real life, some one says find what this is, they don't tell you what to do or how to solve it. You need to use the knowledge you have, learn to filter out extra information, and apply it to get a solution. Most people agree that difficulty is important in the learning and development, so I can say with high confidence that learning to solve math problem is much better of teaching people to solve problems then computer games. In fact for a very long time in School, math is about the only area people solve problems. You don't solve problems in English, or history, reading, or anywhere else, it's just memorization, with almost no analytical thinking. The only exception is advanced students in High School who really start to analyze history and literature. So ,you can see how learning Math and Sciences is pretty much the only real learning beyond memorization in School for a long time.

Floccina writes:

But Matt Flipago most real world algebra problems have nothing to do with factoring quadratic equations. It has been my observation that many people who get A's factoring quadratic equations are stumped later in life by problems that require the application of simple algebra. So why not try spending more time drilling them on the very useful basic principles of algebra. My guess is that because the basic principles of algebra are so simple that most everyone could learn to apply them and this would make and inadequate test for the screening (grading/testing) purpose of schooling. Thus I think that it is a case of testing squeezing out education.

K Martin writes:

The education system teaches critical thinking skills throughout the entire curriculum for all ages, beginning in elementary school. Other than the apparent observation that critical thinking is necessary to solve math problems, it is also dispersed throughout the curriculum in areas such as English, Social Studies, and Science, though not as concentrated as high school. Students must answer questions about a passage they were required to read in these subjects, which forces them to use critical thinking skills to answer them. Although many of the questions asked in lower elementary grades (Kindergarten-2nd) are merely based on the context of the reading (since they are only beginning to read), higher elementary grades (3rd-5th) begin to utilize critical thinking skills more frequently to answer more complex problems. Science in particular forces students to use the information they learned and apply it to a particular experiment or problem. Education should be focused not only on feeding students the information required to pass the end of grade exams, but teaching students to apply the information learned to everyday occurrences, which is proven to help them retain that information much longer than simply placing it in their short term memories.

Tracy W writes:

Floccina - I think that's the main advantage of taking more advanced maths courses - that you get the repeated drill in basic algebra while you are learning factoring quadratic equations and then while you are learning calculus and then while you are learning linear algebra or whatever. The study Dan Willingham discusses indicates that it takes years of repetition to get something into permanent memory.

Although perhaps this necessary drilling could be done, and still made interesting, by repeatedly drilling it for a short period of time every morning in maths class.

Scott Scheule writes:


Sorry to take so long to respond. Yes, I was counting the passes, though I was one off on the first video. The second one I got correct.

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