Matt Ridley
gives a profile:
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.
Elsewhere, Eric Michael Johnson
posits that, contrary to the Randian view, human evolution favours altruists, not individualists.
