## the biggest bluff [not a book review]

**I**t came as a surprise to me that the book reviewed in the book review section of Nature of 25 June was a personal account of a professional poker player, The Biggest Bluff by Maria Konnikova. (Surprise enough to write a blog entry!) As I see very little scientific impetus in studying the psychology of poker players and the associated decision making. Obviously, *this is not a book review*, but a review of the book review. (Although the NYT published a rather extensive extract of the book, from which I cannot detect anything deep from a game-theory viewpoint. Apart from the maybe-not-so-deep message that psychology matters a lot in poker…) Which does not bring much incentive for those uninterested (or worse) in money games like poker. Even when “a heap of Bayesian model-building [is] thrown in”, as the review mixes randomness and luck, while seeing the book as teaching the reader “how to play the game of life”, a type of self-improvement vending line one hardly expects to read in a scientific journal. (But again I have never understood the point in playing poker…)

August 14, 2020 at 2:55 pm

Poker is applied Bayesian decision theory; you’ve got the (reasonably well-modelled as) “aleatoric” probabilities from the cards, a modelling problem regarding the information players leak with their moves (and tells, if you can spot any), and a posterior expected loss function to minimize.

August 14, 2020 at 7:40 pm

I understand these arguments, to a point, but my fundamental quandary is that I cannot see the incentive of playing this card game without involving money and that I have some personal ethical issues with playing with money!

August 14, 2020 at 6:37 am

There is also a summary article in

The Atlantic. I have recently bought the book, recommended by my (older) son who is both a good poker player and a very successful financial trader. (And he paints!) Pardon the paternal pride, he’s no slouch: a double degree undergraduate from Harvard (Physics and Maths) with a Masters from the same in Applied Maths.I’ll let you know.

All this said, I know next to nothing about poker. I have tried in the past, but I can’t quite put probabilities together with tactics.

I understand your “But I’m only a beginner” in your comment about poker, and I deeply admire it. For you are massively more knowledgeable and talented than I. And the Zen “only a beginner” fits you well. I try to do that too, albeit poorly.

This is an interesting subject. From what I understand of the history, didn’t the supermind Laplace begin his path towards Bayesian analysis by considering problems of how to distribute the pot if the game is terminated early?

August 14, 2020 at 10:16 am

Thank you. I have never heard of a connection between Laplace and card games, as opposed to Pascal, de Moivre or Bernoulli.

August 14, 2020 at 8:42 pm

So I looked up Laplace, gambling, and card games of chance in order to confirm my recollection. In the narrow sense, as far as I can tell, he did not specifically address card games, and I am wrong there. However, the “problem of points”, which he addressed in Mémoire sur la probabilité des causes par les év&eacuate;nement”, introduced a general, Bayesian version of the problem and, to the degree, the distribution could be from a card game, because of the generality of the problem, he did. (See Gorroochurn [2014] for the general context and a summary of Laplace’s approach.) But, of course, Laplace did consider gambling problems, for instance, in Chapter 4, “Concerning Hope”, in

Philosophical Essay on Probabilities, with his Eighth, Ninth, and Tenth Principles.August 18, 2020 at 7:03 pm

Laplace indeed mentioned gambling in l’Essai Philosophie, I had all forgotten about this. Thank you.