There are several factors that may have predisposed you to the night life. And, naturally, my colleagues have tried to determine what your sleep preference says about you. Are you neurotic? Conscientious? Intelligent? Disorganized? Blame your suprachiasmatic nucleus.

The mind seems to be wired for negative thoughts. Common wisdom says that pessimism is a problem. The anti-pessimists warn us: “don’t think like that or you’ll doom yourself to failure!” But common wisdom can be wrong, and pessimism can be helpful – if it is done correctly. So cinch up your belt and suspenders, and let’s find the positive side of negative thinking!