本研究以功能性腦造影實驗探索機率資訊不確定對風險決策之影響。我們發現在兩選項間機率差距小之機率判斷作業中，參與者普遍趨避機率資訊模糊之選項，並且違反複合風險下之轉換公理。雖然兩效應之間並無關聯，但參與者展現之模糊趨避程度，卻與其在樂透選擇作業中，偏好固定報酬選項之傾向有強烈連結。而腦造影分析結果除觀察到模糊趨避與複合風險效應背後有不同之神經迴路之作用；也發現越模糊趨避之參與者，其上頂葉在機率判斷與樂透選擇作業中，皆相對越不活化，或爲本實驗中不同作業下類似趨避行爲之共同來源。

The present research examines how uncertainty in probability information may shape decision making when facing risk with an fMRI experiment. In a probability evaluation task where the probability differences between binary choices is insignificant, we find participants usually avert the options with ambiguous probability information and violate the axiom of reduction of compound lotteries (ROCL) . Although the two effects are not related, the exhibited tendency of ambiguity aversion is closely linked to the participant’s preference towards the constant reward when choosing between that and a lottery. In addition to identifying the distinct neural networks underlying ambiguity aversion and the violation of ROCL, the brain imaging analyses from both the probability evaluation and lottery choice task find decreased brain activity in the superior parietal lobule for participants with a stronger tendency for ambiguity aversion and suggest a possible common source for the similar aversive behavior.