http://news.yahoo.com/s/livescience/...meanlongerlife
"Brains are good for more than acing exams. Turns out, nerdy noggins also help primates like us live longer, anthropologists say. Scientists have long pondered the reason for humans' and other primates'
relatively hefty heads. Elephants boast the biggest brains by volume of all land animals, but relative to body size, humans hold the brain-size record."
Well it seems very interesting. Though I'm not really sure whether the difference of size of brains between humans is very negligible, so the difference of life between humans is probably irrelevant. Interesting, but I don't see too many actual applications to this.