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I Knew You Would Say That

June 1, 2003
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A review of David G. Myers’ Intuition: It’s Powers and Perils.

Imagine yourself a contestant on the classic television game show Let’s Make a Deal. You must choose one of three doors, behind one of which is a brand new automobile (while the other two harbor goats). You choose door number one. Host Monty Hall, who knows what is behind all the doors, shows you what’s behind door number two, a goat, then inquires: would you like keep the door you chose or switch? It’s 50/50 so it doesn’t matter, right?

Wrong. You had a one in three chance to start, but now that Monty has shown you one of the losing doors, you have a 2/3rds chance of winning by switching doors. Think of it this way: There are 10 doors; you choose door number one and Monty shows you door numbers 2 through 9, all losers. Now you would switch because your chances increase from 1/10 to 9/10. This is a counterintuitive problem that drives people batty, including mathematicians, and is just one of numerous examples presented by Hope College psychologist David G. Myers in his latest book on the “powers and perils” of intuition.

The perils are legion. Gamblers’ intuitions, for example, are notoriously flawed (to the profitable delight of casino operators). You’ve hit five reds in a row on the roulette wheel. Should you stay with red because you are on a “hot streak” or should you switch because black is “due”? It doesn’t matter because the roulette wheel has no memory, but try telling that to the happy gambler whose pile of chips grows before his eyes.

What about hot streaks in sports? Intuitively don’t we just know that when Kobe’s hot he can’t miss? Intuitively yes, but Myers presents the findings of a fascinating 1985 study of “hot hands” in basketball by Thomas Gilovich, Robert Vallone, and Amos Tversky, who analyzed every basket shot by the Philadelphia 76ers for an entire season. They discovered that the probability of a player hitting a second shot did not increase following an initial successful basket (beyond what one would expect by chance and the average shooting percentage of the player). What they found is so counter-intuitive that it is jarring to the sensibilities: the number of streaks, or successful baskets in sequence, did not exceed the predictions of a statistical coin-flip model. That is, if you conduct a coin flipping experiment and record heads or tails, you will shortly encounter streaks. On average and in the long run, you will flip five heads or tails in a row once in every 32 sequences of five tosses. (Since we are dealing with professional basketball players instead of coins, adjustments have to be made. If a player’s shooting percentage is 60 percent, for example, we would expect, by chance, that he will sink six baskets in a row once for every 20 sequences of six shots attempted.) Players may feel “hot” when they have games that fall into the high range of chance expectations, but science shows that this intuition is an illusion.

Myers systematically catalogues the countless ways our intuitions about the world lead us astray: we rewrite our past to fit present beliefs and moods, we badly misinterpret the source and meaning of our emotions, we are subject to the hindsight bias where we falsely surmise that we knew it all along, we succumb to the self-serving bias where we think we are far more important than we really are, we see illusory correlations that do not exist (superstitions), and we fall for the confirmation bias, where we look for and find evidence for what we already believe.

Since I’m a scientist and skeptic Myers’ demonstration that intuition cannot be trusted triggered my own confirmation bias — everyone knows that intuition is just mushy new age nonsense. But as Myers demonstrates through countless well-documented experiments, our intuitions about intuition may be wrong. There is something else going on in the brain. That something else, for lack of a better word (and I do wish there were a better word), is intuition, or what Myers defines as “our capacity for direct knowledge, for immediate insight without observation or reason.”

Consider the research by Harvard’s Nalini Ambady and Robert Rosenthal, who discovered that the evaluation of teachers by students who saw a mere 30-second video of the teacher were remarkably similar to those of students who had taken the course. Even three two-second video clips of the teacher yielded a striking .72 correlation with the course student evaluations!

Occasionally the staccato pacing of Myers’ scientific analysis is jarringly punctuated with such sentimental expressions as “What the conscious mind cannot understand, the heart knows,” and a few too many pithy and over-familiar witticisms of writers and poets. But these are easily overlooked by the hundreds of studies presented to make his case that intuition is a fruitful field of scientific analysis. For example, I was stunned by, and still do not quite know what to make of the experiments by researchers on how unattended stimuli can subtly affect us. Scientists flashed emotionally positive scenes (kitten, romantic couple) or negative scenes (werewolf, dead body) for 47 milliseconds before subjects viewed slides of people. Although subjects reported seeing only a flash of light for the initial emotionally-linked scenes, they gave more positive ratings to people whose photos had been associated with the positive scenes. Something registered somewhere in the brain beneath awareness.

This effect is most striking in brain-damaged patients. Myers describes a woman who is unable to recognize her own hand, and when asked to use her thumb and forefinger to estimate the size of an object was unable to do it. Yet when she reached for the object her thumb and forefinger were correctly placed. Another study revealed that stroke patients who have lost a portion of their visual cortex may be consciously blind in part of their field of vision. When shown a series of sticks they report seeing nothing, yet unerringly identify whether the unseen sticks are vertical or horizontal. That’s weird.

Even for us non brain-damaged folks, subtle perception and learning is ongoing, especially in the social sphere where, Myers speculates, evolution would have designed our brains to be finely tuned to important relationships. The best predictor of how well a psychotherapist will work out for you, for example, is your initial reaction in the first five minutes of the first session (not unlike the first impression on a first date). And research supports another intuition we have that women are more intuitively sensitive to subtle cues: women are better lie detectors than men, are superior in discerning which of two people in a photo was the other’s supervisor, and were more able to tell whether a male-female couple in a photograph is a genuine romantic relationship or a posed phony one.

What is going on here is not fully understood, and I worry that such research will be used to bolster belief in psychic power. Before we say something is out of this world we must first establish that it is not in this world. That has yet to be done with intuition. Intuition is not subliminal perception; it is subtle perception and learning — knowing without knowing that you know. A full scientific explanation is still forthcoming because this is a relatively new field of inquiry, but Myers’s book brilliantly establishes intuition as a legitimate subject of scientific inquiry.

(Yale University Press, 2004, ISBN 0300095317)
This review was originally published in Los Angeles Times.

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7 Comments to “I Knew You Would Say That”

  1. Jerry Hesch Says:

    “Intuition is not subliminal perception; it is subtle perception and learning — knowing without knowing that you know.”
    I love that definition. I always described intuition as an unconscious choice made by a person who has a wealth of experience and may be acting on subtle clues, as opposed to something in the realm of mind reading. Maybe I would add the term at the very end…”or why you know.”
    I intuit that I will put your definition with my addendum on my bulletin board.

  2. Doug Brooks Says:

    There is something that has always bothered me about the problem discussed in the first two paragraphs of your review (I am sure I have seen it somewhere before) – my intuition tells me that once Monty opens door number 2, it doesn’t matter whether I switch or not, and I am not satisfied by the explanation in the second paragraph.

    I think the problem is that by opening door #2, Monty has changed the rules mid-stream – or started a new game. The game starts as a 1 out of 3 chance to win the car; my assumption is that once I make my choice, Monty will let me know whether or not I have won. But instead, he starts a new game. Now the game is a 1 out of 2 chance to win the car. The fact that in a previous game I happened to have chosen one of those doors is irrelevant to what I should do now. My previous choice of door #1 does not magically imbue that door with any quality that changes my odds of winning the new game from 50/50, any more than a roulette wheel player’s successful choice of red on one spin does not change the odds of the wheel hitting red on the next spin.

    I don’t think this analysis would change even if I knew that after I make my first choice, Monty is going to open one of the other doors. I know that once I make my choice, at least one of the remaining doors will have a goat, and that unless Monty wants the game to end, he will open a door that has a goat. Depending on my initial choice, Monty will have either two doors to choose from (if door #1 has the car), or just one. However, unless I can interpret some “tell”, Monty’s choice is not going to affect my odds of winning the new game, or whether I should switch doors.

  3. Thuy Ngo Says:

    I disagree with Mr. Brooks. The chance of you picking the wrong door in the first round is higher (2/3), so it’s better to switch door in round two even if it seems (intuitively) that switching doesn’t matter.

  4. Ian Robinson Says:

    This issue of the three doors was thoroughly analysed in the Sceptical Inquirer about ten years ago and conclusively resolved. Myers is right and Brooks is wrong. [All my back copies are in storage pending a move, or I could give you chapter and verse.] Like Brooks I didn’t believe it at first but then I did the math.

    Ian Robinson
    Rationalist Society of Australia

    PS Check out

  5. Doug Brooks Says:

    Thanks for setting me straight. I take some solace from the Marilyn Vos Savant postings – looks like I was in pretty good company in my error.

  6. Kevin Cline Says:

    On the show, life was not so simple. Myers analysis assumes that the host always opens one door and then gives the contestant the option of switching. But on the show, Monty Hall was much sneakier than that. See the Wikipedia article for more information:

  7. Gabriel Enck Says:

    Only before the opening of a losing door is there a 2/3rds chance of having chosen a losing door. Once Monty reveals either Doors 2 or 3 to be a loser, the outcome with that door being a winner is impossible (0% chance). The probability matrix ( doesn’t reflect that. If a goat is shown to be behind Door 2, (and you chose Door 1), the “GOAT, AUTO, GOAT” outcome is no longer possible, and thus is not part of probability. The only viable outcomes are now either “AUTO, GOAT, GOAT” or “GOAT, GOAT, AUTO”. A 50/50 chance. No matter which door you initially choose, Monty will show a losing door, and then you will have to decide between the two remaining doors which to choose. The choice “to switch” or not isn’t any different than just choosing one of two doors from the outset.

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