Good Day Gordon G.
I would challenge the assumption upon which your question rests. Why is emotion necessarily "irrational" and why is logic necessarily rational.
Take this recent financial/economic meltdown. We would all say, I think, that people in power (in both politics and business) behaved irrationally, at least in retrospect. After all, "bubbles" in the economy are always irrational, are they not?
We know that many of the exotic derivative instruments used by the financial institutions were created by beings whom one would think among the most "rational" and "logical" of the species -- mathematicians and physicists from M.I.T. (their business of logic and rationality, evidence, is it not?).
But I understand your question, Gordon G. You are talking about the species as a whole, perhaps including the so-called "quants." Still, I am not convinced that emotion is as "emotional" as we sometimes think (in other words, I believe "emotion" has a logic of its own; and I don't think logic is as logical as we sometimes like to think (in other words, I think logic has an "emotion" base, though this emotion is denied).
Anyway, interesting question. I look forward to the other replies you get.
Take it easy, Gordon G.