The proliferation of new neurons is astounding, but as we get older, this capacity decreases.

Nevertheless, neurogenesis  continues even when we get older. The old belief that we’re born with a determined number of neurons, and that throughout life we do nothing more than lose them, is false. There is a decline in neuroplasticity, but the brain continues to be considerably malleable.

Neuroplasticity is the mechanism that produces learning. Each person’s capacity for learning is determined both by genetics and by education. For example, each person’s IQ will, for the most part, be determined by genetics, but intellectual effort can also affect the plasticity o...