Impact of uncertainty and ambiguous outcome phrasing on moral decision-making.

The literature has shown that different types of moral dilemmas elicit discrepant decision patterns. The present research investigated the role of uncertainty in contributing to these decision patterns. Two studies were conducted to examine participants' choices in commonly used dilemmas. Study 1 showed that participants' perceived outcome probabilities were significantly associated with their moral choices, and that these associations were independent from the dilemma type. Study 2 revealed that participants had significantly less preference for killing the individual when the outcome probabilities were stated using the modal verb 'will' than when they were stated using the numerical phrasing of '100%'. Our findings illustrate a discord between experimenter and participant in the interpretation of task instructions.