Monday, 10 November 2014

Deception; Bats

As well as possibly having solved some interesting problems relating to investment in information-acquisition, bats have now been demonstrated actively to jam one another's sonar to interfere with hunting accuracy. This fact alone allows us to make some inferences about the economic constraints that bats face: for example, that food resources are relatively scarce, that there are limited returns from co-operation over hunting, and that thwarting another bat carries a relatively high individual return.

Animal deception is extremely common.  In all its forms, deception always relies on the same underlying principle: the replication of signals associated with a hypothesis, under circumstances where that hypothesis is false.  Sending 'false' signals in this way is usually costly, so in order to evolve (or to present as optimal to a decision-maker), deception must also have a sufficient chance to induce a decision error in at least one one other player in the same strategic game (i.e. someone whose decision can affect your payoff, e.g. a fellow bat).  This isn't a very demanding set of circumstances, hence the ubiquity of deceptive behaviour.

Johnny Chan vs Erik Seidel in the final of the 1988 World Series of Poker

Of course, the evolutionary (and strategic) response to deception is to increase investment in information gathering and processing.  But, as with the bats, it won't necessarily be possible to negate the impact of deception on your own decision-making, and even if it is possible, it won't always be worth the expense.  Poker presents an interesting case study.  Poker is complex enough that optimal strategies have only been explicitly derived for a few of its very restrictive forms.  But it is straightforward to show that, as with many games of asymmetric information, any such strategy must entail opportunistic and sometimes-random bluffing to mask the strength of one's hand. Optimal poker strategy will inevitably entail making mistakes: calling in a position of relative weakness and folding in a position of relative strength.  In poker, as with real life, being deceived doesn't mean you're playing wrongly.

"You know where you are with a complete liar, but when a chap mixes some truth with his yarns, you can't trust a word he says." - The Horse's Mouth (1944), Joyce Cary

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