Question

Which explanation is most likely the reason for the evolution of a larger brain in humans? The size of the human brain increases the more it is used. A larger brain allows humans to solve complex problems. The size of the human brain has changed randomly over time due to mutations. A large brain increases humans’ ability to fight and survive disease.

Answer 1

A large brain allows humans to solve complex problems. This, in turn, has allowed humans with bigger brains to survive better than humans with smaller brains.

Answer 2

Across nearly seven million years, the human brain has tripled in size. The most likely the reason for the evolution of a larger brain in humans is that a larger brain allows humans to solve complex problems. Large, complex brains  enable humans to process and store a lot of information and to interact with each other and with their surroundings better. The  brain we now humans have is the largest and most complex of any living primate.