I saw some science show or some segment on the news that talked about the human brain. One of the things they said was that the human cerebellum was larger in proportion to the rest of the brain then in any other animal.  I knew this was false, I've seen pictures of dolphin brains, but since then, by doing my own resaerch, I've learned that human beings really don't hold this distinction at all. It bothered me that something so patently untrue would be promted as fact. But, of course, that's not a question. My question is: What exactly is the cerebellum used for? I was informed (On the science show) that it was used to calculate distances in a three-dimensional sphere. And that our (enormous) cerebellum was the legacy of our tree-dwelling ancestors who would have needed this ability. It still seems to be a lot of brain dedicated to something that seems fairly simple (To me).

See http://en.wikipedia.org/wiki/Cerebellum (I have read it to ensure the information is correct!). From a clinical perspective the diseases that most commonly affect the cerebellum are stroke and multiple sclerosis. Both cause high pitched and slurred speech (often referred to as Donald-Duck like), problems with balance (see Jed Bartlet in the West Wing in series 6) and difficulty with co-ordination and fine movements eg doing up buttons.

One of the tests we often use to assess cerbellar function is to ask the person to touch their nose and then the observer's finger tip, and then go back and forth between the two rapidly. The obserber then moves their finger to make it more difficult. Very often someone with a cerebellar lesion will have what is called "past pointing" ie they miss the observer's finger.

I leave it my colleagues to talk about the relative sizes and functions of the cerebellum in other animals.

Susan,

Is it possible that you misheard or misremembered what was said on the science show, and that they in fact said that the cerebrum is proportionally larger in humans?