Poker Face

I spent a fair amount of time hanging out with professional poker players while writing How We Decide. For the most part, these players have exquisite control over their facial expressions, so that those micro-muscles around the eyes and mouth rarely betrayed their inner thoughts. (The players reacted with the same look of unflappable boredom to a pair of aces and a hand with mismatched number cards.) But I was always amused by their insistence on wearing opaque sunglasses inside the dimly lit casino. What relevant information did they think their eyeballs would betray? (Most muttered something about dilating pupils.) It turns out, though, that the players were right to shield their eyes, as a new Current Biology paper proves:

Here, we demonstrate how the eyes and their position give an insight into the nature of the systematic choices made by the brain's 'random number generator'. By measuring a person's vertical and horizontal eye position, we were able to predict with reliable confidence the size of the next number -- before it was spoken. Specifically, a leftward and downward change in eye position announced that the next number would be smaller than the last. Correspondingly, if the eyes changed position to the right and upward, it forecast that the next number would be larger. Apart from supporting the old wisdom that it is often the eyes that betray the mind, the findings highlight the intricate links between supposedly abstract thought processes, the body's actions and the world around us.

The larger lesson is that the brain can't escape its embodiment. Even abstract information - and what's more abstract than a random number? - is subject to the heuristics of physical movement: Up means higher, down means lower. Because the mundane world of Newtonian physics is built into the mind at such a basic level, we are forced to re-use these same mental shortcuts when thinking about math, or playing poker. I think experiments like this also explain why it's so much harder to understand quantum mechanics, or string theory. (I'm referring to an intuitive, visceral kind of understanding. As Niels Bohr once said, "Anyone who is not shocked by quantum theory has not understood it.") We simply weren't built to think about wave-particle duality, or the possibility of 11 hidden dimensions. It makes no sense to us. Our eyes don't know how to move.

PS. For another cool study of embodied cognition, check out this post on Neurophilosophy.


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Wow, i gotta check this theory out next time I play poker. It's amazing that subtle muscle contractions such as these can give so much away about the brain's state. What's really cool is that if you use botox to block facial muscles of a person, there's evidence that you can actually dampen their experience of their own emotions. So these subtle muscle contractions aren't just an product of the state of the brain, they are actually part of the state of the brain.

This is an excellent paper but the link with poker players is tenuous at best (although it was pointed to in the press release for the paper). The authors had the subjects speak a (pseudo - subject chosen) random sequence of numbers and then recovered from their eye movement certain characteristics of the sequence. There was nothing about cards, nor anything about whether or not these eye movements can be consciously suppressed. This is good science and also cool science. It blows my mind that people who write press releases (and, sadly, blogs) think it should be stretched to or past breaking point to make it interesting. It's already interesting.


I'm a theoretical physicist, and I understand quantum mechanics at a visceral level. It
wasn't very easy, and it required extensive training, but it's not impossible. (As for string theory, only time will tell if it's possible to understand it; unlike quantum mechanics, we don't yet know string theory's basic principles, or even if the theory will ultimately be self-consistent.)

In the future, please consider refraining from making strident claims about scientific fields outside your own area of expertise. Just because a subject seems conceptually opaque to a brilliant fellow like you, and even to some of its actual practitioners, doesn't mean that it's opaque to everyone.

Thanks for your feedback. CM: I think there is a tenuous but justifiable link to poker.The interpretation of other players is always an act of informed guessing. I see such eye movements, which are based in this experiment on an internal generation of random numbers, to be yet another piece of information than can inform such guesses.

As for quantum physics...Fair point, Matt. I'll tweak the post accordingly. Thanks.

Thanks Jonah! The phrasing is right on the mark now.

These subjects are indeed very hard to understand. But if my word is worth anything, I can tell you that the rewards (both practical and intellectually aesthetic) for devoting the years to understanding them are immense.

Quantum mechanics, in particular, is just about the most beautiful theoretical framework I've ever encountered; indeed, when I teach the subject, one of my primary aims is to try my best to make this incredible simplicity and beauty accessible to my students.

Quantum mechanics really is one of the best examples of a subject that exhibits such a vast divergence between the messiness of its popular appearance and the sublime simplicity and elegance that one finds after getting to its core.

I think the comment above found the link to poker tenuous because there's no real reason to think poker players are worried about these horizontal and vertical eye movements when they are playing poker.

Actually, many professional poker players wear dark or opaque glasses not because they don't want people to see HOW their eyes look, but rather they don't want people to see WHERE their eyes look. They don't want you to know they're looking right at you, because then you will be on guard.

You could do another piece on our subconscious reactions to eyes looking at us and that would be a stronger link to poker.

In Prof. Paul Ekman's "Emotions Revealed," (ISBN: 029760757X), there is an fun-to-do face recognition test in the appendix. When I tried the test I only got 30% right; I did not therefore pursue a career as a professional gambler. Try the test yourself.

By OftenWrongTed (not verified) on 26 Apr 2010 #permalink

I must concur with Jonah's original suggestion (contra Matt) that our brains largely operate within a Newtonian worldview. This is not to suggest that quantum physics is not intellectually beautiful, for it is, but rather that the world in which our brains operate on a day to day basis, Newtonian mechanics work, or at least work well enough. Our brains evolved in a world that, at a first approximation is Newtonian and this is reflected in the way our brains work: the brain takes Newtonian mechanics into account in interpreting the world around us (i.e. our somatosensory systems - a particularly good example is the the use of semi-circular canals and their input to help maintain our balance), and the brain uses principles of Newtonian mechanics to interact with that world (i.e. our motor systems). That such evolutionarily inscribed phenomena are reflected in nuanced behaviour such as eye movements associated with abstract thoughts is on the one hand remarkable and on the other perfectly normal.


At the risk of commencing an internet debate, I'd like to point out that if we're talking about the human brain's natural, untrained state of affairs, then even assuming that it comprehends Newtonian physics is being too generous.

The human brain's innate, uneducated understanding of physics is Aristotelian; it takes education and the acceptance of initially counterintuitive principles for the human brain to acclimate to Newtonian physics; just ask a non-physics major whether a marble falls faster than a ping pong ball, or whether an object's natural state is always at rest.

But my point is that, with sufficient training and experience, new physics concepts do eventually come to seem natural and intuitive. Sure, our brains, in their pristine state, may not intuitively understand such physical principles, but neither do they initially intuitively understand the behavior of chess pieces or of differential geometry.

But years of training can have profound effects on what the human brain finds intuitive. Not all people who use the mathematical formalism of quantum mechanics (or special relativity, or, for that matter, even Newtonian physics) comprehend it at an intuitive level---understand its elementary ingredients and have a visceral understanding of how they behave---but some do.

Do the left-handed react in the opposite manner? Brain hemispheres and all that.

By Colin Laney (not verified) on 28 Apr 2010 #permalink

"The human brain's innate, uneducated understanding of physics is Aristotelian; it takes education and the acceptance of initially counterintuitive principles for the human brain to acclimate to Newtonian physics; just ask a non-physics major whether a marble falls faster than a ping pong ball, or whether an object's natural state is always at rest."

Is it clear that this is innate? How would one know that it isn't learned behavior?

Colin is right that Newtonian physics is not intuitive. It took an extraordinarily imaginative and radical thinker to come up with it, relatively late in human history. But I fail to see the connection between the eye-movement study and Newtonian physics at all."Up means higher, down means lower" is Newtonian?

I think there's some confusion here. Jim-- I did not say that Newtonian physics was innate. Precisely the opposite. I was specifically countering the notion that Newtonian physics was innate, and more so than, say, quantum mechanics.

My point was that if any notion of physics was innate to the human brain, it's probably pre-Newtonian, Aristotelian physics. Of course, as Colin points out, there's a case that even Aristotelian must be learned.

In any event, all of this is orthogonal to my main point, which is that whatever may or may not be innate, many notions of physics can become intuitive and visceral through years of training and experience.

Of course, even many practitioners of these subjects never reach that stage of visceral understanding, relying on solely on mathematical formalism to carry them through. Especially in quantum mechanics, many people who have become very practically successful through the use of the mathematical formalism (including many of the very early practitioners of quantum mechanics) believe that it's impossible to develop a truly intuitive understanding of the subject.

That's where I, and many others, would disagree, especially thanks to a number of foundational developments in the last three decades that have not leaked out very much into the popular depictions of quantum mechanics amongst the general public.

Andrew Sullivan's summary: "Why You Can't Understand String Theory? Your eyes don't know how to move."

I think that about sums up the validity of what you're saying.

Oops. Sorry, Matt. I didn't see the quote marks in Colin's statement. It was actually _your_ point about Newtonian physics that I was agreeing with. But Jonah's linkage between eye movements ("Up means higher, down means lower") seemed an unwarranted leap to me.

Hi, I'm an extremely specific case of a particular minority within the fields of science, and I object to the generalized statement you made that describes an obvious case regarding the public at large. I feel that my tiny, statistically irrelevant deviation from the norm completely and unequivocally discredits your argument, and I feel compelled to let everyone know via a series of snarky internet message board comments.

By Arrogant Asshat (not verified) on 28 Apr 2010 #permalink

Why do people feel the need to get personal in their attacks? A strong argument shouldn't require cowardly, anonymous, ad hominem attacks.

My point in originally posting was to counter a widely held misconception that even the practioners of modern physics are baffled by quantum mechanics. That's a specific misconception, and it deserves a respectful critique. I made no attempt to be "snarky," and I was speaking not about a statistically irrelevant group of people, but about physicists, who are precisely the group at the heart of the discussion.

I was also attempting to argue the defensible position that intuition can be developed through training and experience, even for subjects that are far removed from the occurrences of daily life.

If anyone here disagrees with those positions, then please feel free to object respectfully. But don't distort my claims, or otherwise be an "arrogant asshat" about it.

Cheers for the reply Jonah. You often point to really interesting work, which is why I read your blog. You're also often carried away on flights of fancy which depart from science - so am I! I'm just a little jealous that you get to write them down and run with them wherever they go, whereas I have to put them in my notebook and one day hope to run the experiment. It's a good line of work you have and I appreciate that you're keeping people interested in science. Peace.