How were stone age people different from you?

The people themselves? They ARE us.

If you could pick up a cave man and a cave woman from 50,000 years ago and bring them to today, their baby would be as fully human as you are. Given proper nutrition and medical care, that baby could grow to be a doctor, a scientist, an engineer, a plumber, an author - whatever. The parents, having been raised in a cave on a terrible starvation diet, wouldn't be as fortunate, and might never learn to speak properly, but that's a product of the environment, not the genetics.

(Actually, you would want to pick up a cave man from one place and a cave woman from another, because primitive cavepeople were pretty inbred; not a whole lot of genetic diversity. One reason why humans today are healthier and smarter than our ancestors only 200 years ago is that our ancestors 200 years ago didn't travel much and married their close cousins - because there was nobody else. The railroad was the greatest genetic engineering experiment of all time, because it was now possible to meet and marry somebody who was NOT your cousin.)