Freud meets Darwin.

In his Psychology 101 lecture at Yale University, Dr. Paul Bloom asks, from an evolutionary standpoint, "Why would an unconscious evolve?"

To deceive. To deceive ourselves, so that we can better deceive others.

Dr. Bloom explains; “deception defined broadly is simply to act or be in some way that fools others into believing or thinking or responding to something that's false.”

Animals do it. Cats arch their backs and toads make their throats swell so they look bigger and more tough than they really are.

Dr. Bloom notes that people do it too. We puff up our chests and try to trick others into believing that we're “smarter, sexier, more reliable, (and) more trustworthy” than we really are.

But there’s a catch. Humans have evolved good lie detection mechanisms. If I can tell that you are faking being tough, you lose the reproductive advantage. If you are going to pass on your genes, you need to be a really good liar.

So how do you become a good liar? Here is where the unconscious comes in. Since the best lies are the lies we believe, our ancient forebears who believed their own lies, had the evolutionary edge.

The unconscious mind evolved so that we can lie to ourselves better, so that we can lie to each other better, so that we can have an honest shot at reproducing.