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January 27, 2007

Fish are the new birds?

Given my apparent fascination with bird brains, and their evident ability to functionally imitate mammalian brains, imagine my surprise to discover that fish (specifically the males of a species of cichlid called A. burtoni) employ similar logical inference techniques to birds and mammals. The experimental setup allowed a bystander cichlid to observe fights between five others, through which a social hierarchy of A > B > C > D > E was constructed. In subsequent pairings between the bystander and the members of the hierarchy, the bystander preferred pairing with the losers in the hierarchy, i.e., near E and D. The idea is that the bystander is hedging his bet on where he stands in the hierarchy by preferring to fight losers over winners.

One interesting implication of this study is that logical inference - in this case something called "transitive inference", which allows the user to use chains of relationships to infer additional relationships that shortcut the chain, e.g., A > B and B > C implies A > C - maybe have evolved extremely early in the history of life; alternatively, it could be that the ability to do logical inference is something that brains can acquire relatively quickly when natural selection favors it slightly. In the case of the cichlids, it may be that the development of transitive inference evolved in tandem with their becoming highly territorial.

I wonder what other cerebral capabilities fish and birds have in common...

L. Grosenick, T. S. Clement and R. D. Fernald, "Fish can infer social rank by observation alone." Nature 445, 429 (2007).

posted January 27, 2007 12:43 PM in Obsession with birds | permalink


OK, so I just belatedly looked at your 'year in review' entry and I can't comment there, so I'll put this here.

Your 'e-mails sent' will probably go waaaaaay up as your career progresses. I typically send more than 500 a _month_, so your 1300 a year seems pretty low to me. :)

Granted, I also use e-mail to keep in touch with people, so it's not like all 1300 of those were for work. The number of non-spam I received is also ridiculously high, but I like getting mail as long as it doesn't ask me to do anything.

Posted by: Mason at January 28, 2007 03:01 PM

Yeah, the 1300 number is already a huge underestimate because I routinely go back through my sent-mail folder and delete stuff that I don't think I'll ever need to see again - it just turned out that at the end of 2006, there were 1300 that I hadn't deleted. The real number could easily be two or three times that number. And yeah, I fully expect it to get much larger in the future.

Sometimes, Mark or Cris make comments to me about the number of email they receive. At this point, it boggles my mind that they manage to stay on top of their huge volume, but maybe I just have that perception because they typically respond to things I send them!

Posted by: Aaron at January 28, 2007 07:10 PM