Modern humans have brains that are more than three times larger than our closest living relatives chimpanzees and bonobos and we have the gradual increase in brain size of our ancestors over the past three million years to thank for that a new study says. The study published in the journal Proceedings of the Royal Society B involved an analysis of 94 hominin fossils. It showed that brain size increased gradually and consistently driven by evolution within populations introduction of larger-brained species and extinction of smaller-brained ones. Brain size is one of the most obvious traits that makes us human.
