Is there any advantage to having a big brain?

Anthropologists have long measured the skull's interior volume and compared it against body size to arrive at a rough estimate of intelligence. These measurements are known as encephalization quotients.

However, as brain-imaging techniques have improved, scientists have been able to measure brains with far greater precision.

But the questions remain: What should we measure? Is it size or is it neurons? Is it circumference or weight? Should encephalization quotients use lean body mass or total body weight? Should there even be a correction for body size?

While debate rages on over what is the best measure of brain size, that has not stopped some researcher s from drawing conclusions.

Psychologist Michael McDaniel in 2005 evaluated studies that used standard intelligence tests and brain-imaging results and found that bigger brains, unequivocally, correlated with smarter people.