「如果我當初買的是A公司股票，我就不會賠錢了！」 後悔 (regret) 是一種讓人感到痛苦、覺得自己犯了錯、想要再重來一次的負面情緒。它是反事實比較 (counterfactual comparison) 的結果，發生在當我們瞭解到或想像到如果當初做了不一樣的決定，我們目前的情況應該會變得更好。而那個當初放棄的方案（如A公司股票）便是消費者進行比較的參考點 (reference point)。儘管愈來愈多學者指出，消費者的後悔情緒可能受不同參考點的影響，但卻缺乏相關研究。本論文即在探討多參考點對消費者決策後悔之影響。透過539位MBA 和EMBA 學生，以及 227 位股票投資人所參與的二個研究，本研究發現：(1) 消費者決策後悔會受到多個參考點影響，這些參考點包括無為 (inaction)、期望和較佳之放棄方案；(2) 在這些參考點中，無為對消費者決策後悔之影響最大；此外，(3) 決策後悔主要受到損益 (losses or gains) 的影響而非損益的大小 (the size of the loss or gain)。本研究發現對後續有關消費者後悔情緒的研究具有重大影響。 Regret is the result of a comparison between “what is” and “what might have been”. Although regret is a relevant emotion in our daily life, research studying how regrets are influenced by multiple reference points is lacking. This dissertation presents two studies that investigated the regrets of decision makers in relation to multiple “what might have been” scenarios. In the context of a choice set comprising three alternatives, the first study of 539 MBA and EMBA students demonstrated that people use multiple reference points in judging their post-decisional regrets. The second study of 227 real stock investors in a field survey further showed that investors’ regrets are most influenced by what their outcomes might have been had they not invested, by their expected outcomes and by the best-performing rejected stocks. Among these reference points, the non-investment (inaction) outcome has the largest impact on regret. In addition, we also found that the feeling of regret was influenced by losses or gains relative to each reference point rather than by the size of the loss or gain. Several theoretical and managerial implications are discussed and future research directions are suggested.