Here's a hybrid story, relating to both of the above. Persi was called in at one point to investigate a team in duplicate that was winning more often than expected after making counter-probabilistic plays. These arose, he eventually discovered, because of the previous players at that table not shuffling their individual hands much before leaving them. The team under investigation was gleaning some information about the play of the previous hand, based on the orderings of the cards left for them. Persi has a nearly unlimited number of great anecdotes on the subject, so actually I have no problem believing Bernie's (2), though. --Michael On Fri, Jul 8, 2011 at 12:07 PM, Bernie Cosell <bernie@fantasyfarm.com>wrote:
On 8 Jul 2011 at 11:28, Andy Latto wrote:
On Thu, Jul 7, 2011 at 6:17 PM, Bernie Cosell <bernie@fantasyfarm.com> wrote:
2) bridge masters seemed to occasionally make counter-probabilistic plays [playing finesses and for suit splits, etc], but as a corollary to (1), he discovered that their play was actually correct for the *actual* probabilities [due to the inadequate shuffles].
I've seen this claim before, but I don't believe it.
I've never seen a source for it. I've read Persi Diaconis' paper on shuffling, and it's not there. I read the bridge publications that the experts read, such as "The Bridge World", and I've never seen it there. I've talked to a friend who has represented the US in the Bermuda Bowl (the most prestigious of the world championships), and he's never heard anything like that from any experts.
I heard it from Persi, directly, when he came to BBN and gave us a lecture on this and other things he was working on [how to flip a coin fairly, etc]. This would have been maybe 1980 or so [???] -- it was after the Newman auditorium was opened, so I guess it couldn't have been really back in the old days... I never followed up on it but it just stuck as an oddity. [my thought was that it seemed very surprising, because it is hard to imagine anyone, even a full time professional player, playing enough hands to detect, notice, quantify and take advantage of such a very small deviation. Sort of like, how many times do you have to flip a coin to decide it is every so slightly biased]
/B\
-- Bernie Cosell Fantasy Farm Fibers mailto:bernie@fantasyfarm.com Pearisburg, VA --> Too many people, too few sheep <--
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