The Case Against Reality: Why Evolution Hid the Truth from Our Eyes

by Donald D. Hoffman

The notion that our brains are growing in size, and thus in their capacity to see truth, also conflicts with a fact of our evolution: our brains are shrinking.22 In the last 20,000 years, our brains have shrunk 10 percent—from 1,500 cubic centimeters down to 1,350—a loss of the volume of a tennis ball. Our encephalization quotient, or EQ, which compares our ratio of brain mass to body mass with the average ratio for other mammals, has plunged in an eye blink of evolutionary time. According to the fossil record, this plunge correlates slightly with climate, but heavily with population density and thus, we can presume, with social complexity. This suggests an interesting explanation: the safety net of society eases selection pressures on members; some who wouldn’t survive alone, or in small groups, can survive with a larger social net. This possibility, explored with humor in the movie Idiocracy, is speculation for now. But the plunge of our EQ is not. If it continues apace it will, within 30,000 years, send our brains back half a million years, to the size of Homo erectus. Our brains took the escalator up; they’re on the elevator down.