消費者對於無效的優惠活動,例如,已過期、身分不符或購買數量不足等,在理性決策分析中,對現下的購買決策理應不具影響。然而過去學者已經發現當其他客觀商品的存在會影響,目標商品的主觀評價(Ariely and Wallsten, 1995; Simonson and Tversky, 1992)。因此,本研究推論無法享有的優惠商品(Y),將影響目標商品(X)的主觀評價,進而造成非理性的決策行為。本研究歸其原因為「或有損失」,例如,早知道就好、如果我是學生就好等造成的心理損失。除「或有損失」外,本研究也繼續探討「或有利得」以及「或有訊息」,亦即或有利得─真慶幸是我擁有;或有訊息─如果我要多買的話、如果我要買別的話。以上「或有損失」、「或有利得」及「或有訊息」即為本研究所要定義的「或有心理」的三個主要消費者心理運作模式與架構。 In the behavioral economics field, Ariely, and Wallsten (1995); Simonson and Tversky (1992) have proposed that decision makers in the different choice set will have different subjective judgment, in the same objective stuff, such as the extremeness aversion and the asymmetric dominance effect. Therefore, this paper hypothesizes that one invalid promotional campaign (discount, coupon et.) will affect how a product is judged subjectively. In other words, some mental states like “ if I were there” or “if I would buy more” would actually affect the irrational behavior. This can be called as “probable loss”. This thesis thereafter proposes and examines several psychological antecedents of the effect, such as “probable loss by time, “probable gain” and “probable signal”.