Sunday, March 9, 2008

Logical Fish

It seems like not a day goes by without a new study demonstrating fish have more on the ball than anyone ever thought. Last week, we learned that fish can do math. In this latest study, researchers at Stanford University demonstrated that a species of Cichlids (from same family as Oscars - like Snow and Ice), were able to perform transitive inference.

The fish observed face-offs between 5 identifiable fish of the same species in an adjacent tank. By watching the fights, the fish were able to determine the 'pecking order' of the five other fish. When placed in the tank with pairs of fish from the five that they'd never seen fight each other, they chose to hang out with the weaker of the pair, knowing they'd be less likely to get picked on that way.

The researchers said this type of logical reasoning is a developmental milestone for human children, showing up nonverbally as early as ages 4 and 5; it also has been reported in monkeys, rats and birds. It is the kind of thinking that allows people (and animals) to reason that if A is bigger than B, and B is bigger than C, then A is also bigger than C.

This is another example where a fish's ability to learn, in this case, about the dominance hierarchy of other fish in its evironment, would provide significant survival advantage.


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