Re: Free will, still more

Eliezer Yudkowsky (
Mon, 03 Feb 1997 18:37:37 -0600

[Eric Watt Forste wonders:]
> I thought the cerebellum was involved in fine-scale motor coordination,
> not in conceptual recall. Are you sure you aren't meaning to say
> "cerebral cortex" instead of cerebellum? That's a guess on my
> part... you've really lost me.

Welcome to one of the big surprises of cognitive science. We know the
hippocampus is involved in LTM (long-term memory) formation, because
people who lose the hippocampus can't form new memories - although, in
retrospect, they can retrieve the old LTM just fine.

So, with those newfangled PET scanners and other close-to-real-time
neuroimaging tools, they finally get a chance to see what happens when
people *retrieve* LTM. Guess what lights up?

Not the hippocampus.
Not the cerebral cortex.
The cerebellum.

And if anybody can even *begin* to explain this, I haven't heard about
it. My own guess is that the cerebellum does constraint propagation or
some other kind of constraint-to-visualization assembly, and that is
what motor skills, LTM retrieval, and (another guess) spatiotemporal
visualization have in common.

--       Eliezer S. Yudkowsky

Disclaimer:  Unless otherwise specified, I'm not telling you
everything I think I know.