I. Can we choose to be optimistic or pessimistic about our future prospects? Can we choose our appetite for risk or our attitude toward conformity? Can we choose to bolster our self-esteem if we know that low self-esteem is causing us grief? Few of us believe we are entirely free to conduct a sober, sophisticated cost-benefit analysis every time we face an important decision in life, whether it’s how much to study for a final exam, when to end a long-term relationship, or if we should order one last drink before the bar closes. Similarly, few of us believe we live in an entirely deterministic world in which we are free only to rationalize our behavior after the fact. So, how free are we? Science provides us with plenty of empirical evidence to suggest we are not as free as our most exuberant defenders of human freedom assume, but it will likely be a few more decades, if not longer, before neuroscientists, endocrinologists, evolutionary biologists, sociologists, psychologists, and scientists of as-yet-unnamed disciplines identify precisely where …