[Niamh.]

So apparently, this is what a study on this dilemma concludes :

Spoiler:

The Economist reports that only 10% of experimental subjects are willing to throw the stranger under the train. I suspect it would be less, if the subjects found themselves in a real situation, instead of a pretend experimental test. The further result of the experiment is that these 10% of people tend to have personalities that are, "pscyhopathic, Machiavellian, or tended to view life as meaningless."