If you are a carrier of a particular set of genes, your probability of committing a violent crime goes up by eight hundred and eighty-two percent.

When a male vole repeatedly mates with a female, a hormone called vasopressin is released in his brain. The vasopressin binds to receptors in a part of the brain called the nucleus accumbens, and the binding mediates a pleasurable feeling that becomes associated with that female. This locks in the monogamy, which is known as pair-bonding. If you block this hormone, the pair-bonding goes away.

The brain internally simulates what will happen if you were to perform some action under specific conditions. Internal models not only play a role in motor acts (such as catching or dodging) but also underlie conscious perception.

You´re not perceiving what's out there. You're perceiving whatever your brain tells you.

If you cannot always elicit a straight answer from the unconscious brain, how can you access its knowledge? Sometimes the trick is merely to probe what your gut is telling you. So the next time a friend laments that she cannot decide between two options, tell her the easiest way to solve her problem: flip a coin. She should specify which option belongs to heads and which to tails, and then let the coin fly. The important part is to assess her gut feeling after the coin lands. If she feels a subtle sense of relief at being "told" what to do by the coin, that's the right choice for her.

Societies would _not_ be better off if everyone were like Mr Spock, all rationality and no emotion. Instead, a balance - a teaming up of the internal rivals - is optimal for brains. ... Some balance of the emotional and rational systems is needed, and that balance may already be optimized by natural selection in human brains.

Imbalance of reason and emotion may explain the tenacity of religion in societies: world religions are optimized to tap into the emotional networks, and great arguments of reason amount to little against such magnetic pull.