商品市場上充斥著各種方案選擇，在方案間的比較中，有些可以高下立判，讓人快速地做出決策，有些則是吸引力相當，讓人在選擇時猶豫不決，產生決策困難。本研究探討決策難易度(簡單決策/困難決策)以及困難決策類型(兩好屬性策/兩壞屬性決策/一好一壞屬性決策)對於消費者的決策後偏好態度的影響，並且加入涉入、自我監控、認知需要和產品型態四個干擾變數，來衡量對決策後偏好態度的影響。本研究採用實驗研究法進行實驗；共有兩個實驗，透過紙本問卷進行測驗，樣本以中央大學和南開科技大學的學生為主，有效問卷為280份。研究結果顯示：1.困難決策下之決策後偏好態度，在遭遇負面攻擊後下降程度相當高，顯示其較簡單決策下不具持久性。2.困難決策類型對於決策後偏好態度會產生差異之影響。3.在困難決策下，高涉入消費者的決策後偏好態度，在遭遇負面攻擊後下降程度相當高，顯示其較簡單決策下不具持久性。4.在實體產品消費決策下，簡單決策與困難決策之決策後偏好態度無顯著差異；在服務消費決策下，簡單決策與困難決策之決策後偏好態度存在顯著差異。Consumers often face situations of free choice among multiple options in consuming market. When the options are similarly attractive, they can experience difficulty in resolving their preferences to arrive at a purchasing decision. In these contexts, how do consumers react to different decisions between similarly appealing options? The study tries to discuss the effect on post-choice favorable attitude of easy and difficult decisions and three types of difficult decisions, which is choosing greater goods, choosing lesser evils and choosing attribute-conflicts trade-offs . We also adopt involvement, self-monitoring, need for cognition and product form as moderating variables to test the implications for post-choice favorable attitude. The study involves two experiments and the participants were asked to fill out paper-based questionnaire. The main subjects are students of National Central University and Nan Kai University of Technology. The results indicate that:1.Following difficult decision, the post-choice favorable attitude is exceptionally fragile, collapsing easily against even minor attack. The durability of post-choice favorable attitude following difficult decisions is inferior to easy decisions. 2.The types of difficult decisions will lead to different post-choice favorable attitude.3.Heightened involvement in difficult decisions increases the vulnerability of post-choice favorable attitude to subsequent attack.4.In terms of service-consuming decision, post-choice favorable attitude of easy decision is distinct from difficult decision. However, it has no difference between these two decisions in tangible product-consuming.