Does the ability to learn come at a cost to health? According to Carl Zimmer at Science Times, that's the conclusion from research showing that for some animals, being smart doesn't equate with living longer. The big idea, as one biologist in the story suggests, is this:
Dr. Kawecki suspects that each species evolves until it reaches an equilibrium between the costs and benefits of learning. His experiments demonstrate that flies [which he has trained to associate some foods with nourishment and some with predators!] have the genetic potential to become significantly smarter in the wild. But only under his lab conditions does evolution actually move in that direction. In nature, any improvement in learning would cost too much.
That cost is measured in other ways as well. Using the example of human infants, which come into the world in an obvious state of helplessness, another researcher put it this way:
'We use computers with memory that’s almost free, but biological information is costly,' Dr. Dukas said. He added that the costs Dr. Kawecki documented were not smart animals’ only penalties. 'It means you start out in life being inexperienced,' Dr. Dukas said.
"Lots of Animals Learn, but Smarter Isn’t Better" is well worth a few moments of your time.