[Fice]

Pushing the large man is risky, you can't be 100% sure that it will work, and you can't be absolutely sure that five people will die if you don't do it. So it could be the willingness to take chances rather than the moral judgments.

[Ensorceled]

Normally uncooperative subjects like you are simply removed from the study :-)

[krisgee]

In the context of the thought problem it works 100% of the time.

[chroma]

Even if I am confident that pushing a fat man onto some tracks will stop a trolley and save lives, it is much more likely that I have gone insane than that actually being the case. If this dilemma happened in real life, hopefully I would recognize my insanity and not push the fat man.

[Fice]

This is not an abstract logical problem. If you imagine yourself in the situation, it still feels like taking a risk, and this will influence your answer.