This is not a surprise.
In what academics call neoclassical economics, human beings are largely rational, self-interested decision-makers. This stereotypical human, often referred to as Homo economicus, is a creature of coldly calculated selfishness, dispassionately maximizing its best interests even if that comes at the expense of others.
A study in Japan shows that Homo economicus makes up only a minority of the population, but a minority with a wide range of unusual personality traits, including a touch of psychopathy.
More at the link.