Perhaps more intriguingly, when libertarians reacted to moral dilemmas and in other tests, they displayed less emotion, less empathy and less disgust than either conservatives or liberals. They appeared to use “cold” calculation to reach utilitarian conclusions about whether (for instance) to save lives by sacrificing fewer lives. They reached correct, rather than intuitive, answers to math and logic problems, and they enjoyed “effortful and thoughtful cognitive tasks” more than others do.

The researchers found that libertarians had the most “masculine” psychological profile, while liberals had the most feminine, and these results held up even when they examined each gender separately, which “may explain why libertarianism appeals to men more than women.”

All Americans value liberty, but libertarians seem to value it more. For social conservatives, liberty is often a means to the end of rolling back the welfare state, with its lax morals and redistributive taxation, so liberty can be infringed in the bedroom. For liberals, liberty is a way to extend rights to groups perceived to be oppressed, so liberty can be infringed in the boardroom. But for libertarians, liberty is an end in itself, trumping all other moral values.