For starters, that's not natural morality which is a long-standing tradition in its own right. Secondly, to claim that emotions have little to do with the answers given is contextually inappropriate. For example, the question that "Would you drive your boat faster to save the lives of five drowning people knowing that a person in your boat will fall off and drown?" is going to be different in reality to the abstract.

Ultimately, moral reasoning is not a science, as one cannot derive the rightness or wrongness of actions based on their facticity.