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Selective Pressure Drove Up the Encephalization Quotient in Humans
- 2.4 million years ago: MYH16 mutation in genus Homo that may have enabled encephalization.
- 2 million years ago: Evidence of encephalization already underway in genus Homo. Skull size eventually triples to present-day size.
Selective pressure drove the evolution of a variety of social bonding adaptations, including music and language, and thereby drove up the encephalization quotient.
Although a few animals have brains that exceed the size of the human brain, the important thing is the ratio of brain-to-body weight. By this measure, Homo sapiens easily tops the podium as the brainiest species on the planet.
The American palaeontologist Stephen Jay Gould, among others, studied the ratio of brain size to body weight (encephalization quotient) in other hominids and other primates, and concluded, “...our brain has undergone a true increase in size not related to the demands of our larger body. We are, indeed, smarter than we were.”