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Why Transitivity Violations Can Be Rational 169

ananyo writes "Organisms, including humans, are often assumed to be hard-wired by evolution to try to make optimal decisions, to the best of their knowledge. Ranking choices consistently — for example, in selecting food sources — would seem to be one aspect of such rationality. If A is preferred over B, and B over C, then surely A should be selected when the options are just A and C? This seemingly logical ordering of preferences is called transitivity. Furthermore, if A is preferred when both B and C are available, then A should 'rationally' remain the first choice when only A and B are at hand ... But sometimes animals do not display such logic. For example, honeybees and gray jays have been seen to violate the Independence of Irrational Alternatives, and so have hummingbirds ... Researchers have now used a theoretical model to show that, in fact, violations of transitivity can sometimes be the best choice (original paper) for the given situation, and therefore rational. The key is that the various choices might appear or disappear in the future. Then the decision becomes more complicated than a simple, fixed ranking of preferences. So while these choices look irrational, they aren't necessarily."
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Why Transitivity Violations Can Be Rational

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  • by orgelspieler ( 865795 ) <> on Wednesday January 15, 2014 @02:38PM (#45967865) Journal

    They are using the word "rational" to describe a specific, common-sense-to-humans, transitive property of preferences. That is all. You are reading way to much into their choice of words. The whole point of evolution by natural selection is that certain traits emerge because they are adaptive. What this paper sets out to show is that the behavior we see is not "rational" in the common sense, but it is still adaptive. It did not evolve "due to an absurd amount of chaos." They're basically arguing that long-term adaptivity trumps short-term logic.

    Really there's a pretty good allegory to human behavior here. People frequently prefer to do things that are not in their long-term best interest, because they only think about their short-term best interest. Eating your second-favorite chocolate first could lead to your wife only buying milk chocolate, since you obviously like it better. Shooting the guy in the row in front of you might seem like a good way to get him to stop texting, but it's a terrible way to enjoy the rest of your movie. Faking being in the CIA might sound like a great way to get a nice paid vacation, but you will eventually get busted. Groups of people (think governments) are particularly bad at this, too. If I list any examples, I'll get modded as flamebait, but I'm sure you can think of several.

Order and simplification are the first steps toward mastery of a subject -- the actual enemy is the unknown. -- Thomas Mann