What Brains Are For

What do you think brains are for?  Or, more accurately, what is the main thing that brains do?

I would imagine that the most common answer to the question is that brains are for thinking.  When we think of brains we generally think of our own brains, and we think of our own brains as things that do thinking.  Daniel Wolpert advances an excellent hypothesis in the talk below.  His hypothesis is that brains are for adaptable movement.

A brain is not necessary for a species to survive, plants don't have brains.  However, everything that produces complex, adaptable movement (most animals) has a brain.  Without a brain it becomes extraordinarily difficult for a anything to react to the environment, and you can (almost) only react to environment through movement.  The great example he gives in the talk are sea squirts, which at some time in their lives swim around until they find a place to anchor themselves and never leave.  The first thing they do after anchoring themselves is digest their own brains.  They aren't going to move around anymore and so don't need a brain.

You may think that while this may be true for "primitive" animals, our brains are special in that we spend most of our time thinking abstract thoughts, imagining the future.  Even if you think that abstract thought largely doesn't result in some change in the ability to move, i.e. interact with the environment, I would like to put forward Wolpert's observation that the best computers in the world are now better than the best humans at chess and Jeopardy, while it is an entire post-graduate computing project to open a particular bottle of water, filled with a particular amount of water, and pour that water into a particular glass in a particular position.  If you change any of the parameters for pouring the water it is a new post-graduate project.

In terms of some complicated intellectual problems computers are better than humans.  No computer in the world comes close to the computing ability of a three year old in moving around in their environment.  Moving around adaptably is much, much harder than being a grand master at chess.