Some men may be genetically inclined to have and hold a single partner, while some may not. In the near future, young women who stay current with the scientific literature may demand genetic tests of their boyfriends to assess how likely they are to make faithful husbands.

After all, across the population there are slight differences in brain function, and sometimes these translate directly into different ways of experiencing the world. And each individual believes his way is reality.

At least 15 percent of human females possess a genetic mutation that gives them an extra (fourth) type of color photoreceptor - and this allows them to discriminate between colors that look identical to the majority of us with a mere three types of color photoreceptors.

To a space alien or a German Shepherd dog, two humans would be indistinguishable, just as attractive and unattractive space aliens and German Shepherd dogs are difficult for you to tell apart.

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.

Modern neuroimaging is like asking an astronaut in the space shuttle to look out the window and judge how America is doing.

If choices and decisions derive from hidden mental processes, then free choice is either an illusion or, at minimum, more tightly constrained than previously considered.