• Developing a large brain requires a long, arduous gestation period followed by a laborious birthing, complicated by the incompatibility of an infant's large head and a woman's narrow pelvis region (which is necessary to stand on two feet).

• Brain development continues years after birth, extending a human infant's vulnerability and dependency on their parents.

• The brain demands a proportionately larger chunk of our energy, even when at rest, than other parts of our body.

• The brain is maintained by more than half our genes, which are particularly vulnerable to errors, and can result in behavioral disorders.