The author says that there are two brains at work inside your mind: the human and the chimp.

The description of each brain perfectly describes the behaviors of humans and niggers.

One of the easiest ways for us to learn is through analogy. Thatís why, when Steve replaced two complex sounding names for parts of our brain with simpler images, he made a brilliant move as a teacher. He describes
our prefrontal cortex
as the human part of our brain and
our limbic system
as our inner chimp. The human acts rationally, based on facts, but the chimp only decides using emotions.
And since nigger skulls won't allow for prefrontal cortex expansion, they stay relatively stuck in "monkey mode".