Abstract: This paper first examined the effect of causal attribution on mental simulation under the framework of treating causal attribution as one kind of outside force. The results revealed that there is positive correlation between the power of causal attribution over counterfactual thinking with the reason of choice and negative correlation with the outcome of event. The exception-routine effect in counterfactual thinking would disappear in case of minor outcome followed by a significant reason. We distinguish free event and forced event from each other in the basis of the results and propose that the exception-routine effect (or action-inaction effect) should only be applied to free events instead of all events. This finding partly explains the long-lasting differences between scenario experiment and field research on regret and counterfactual thinking

Key words: counterfactual thinking, causal attribution, free and forced event