自1957年Festinger提出認知失調理論後，許多學者便將之應用於消費者行為領域，從事消費者購後失調研究。由於購後失調對滿意度、品牌評價與再購意願有負面影響，因之降低購後失調是重要議題。彙整過去文獻，降低購後失調方法有：提高品牌知名度、增加購後溝通、降低消費者焦慮與提高消費者產品知識，然本研究發現，其中產品知識、焦慮、購後失調三者關係，需進一步探討。本研針對臺灣北部地區某3C、家電量販店四家分店之消費者進行固定樣本兩階段問卷調查，共得有效問卷185份。經階層迴歸分析發現：情境焦慮對購後失調有顯著正向影響；特質焦慮對購後失調有顯著正向影響；特質焦慮亦會干擾情境焦慮對購後失調之影響。經簡單迴歸與複迴歸分析發現：產品知識對購後失調有顯著負向影響；產品知識對情境焦慮有顯著負向影響；情境焦慮為產品知識與購後失調之中介變數（完全中介），換言之產品知識是透過情境焦慮，進而對購後失調有負向影響。此外，本研究亦發現，購買決策涉入對購後失調有顯著正向影響；消費者之產品知覺價值、品牌知名度對購後失調有顯著負向影響。

Since social psychologist Festinger (1957) developed the Cognitive Dissonance Theory, many researchers have applied it on consumer behavior studies. Because consumer Post-Purchase Dissonance will negatively influence on consumers' satisfaction, evaluation of brand and willing to repurchase, discussing the way to decrease Post-Purchase Dissonance is very important. The ways to reduce consumers' Post-Purchase Dissonance are increasing brand awareness, increasing post-purchase communication, decreasing consumers' anxiety, and increasing consumers' product knowledge. However, we find the relationship among Product Knowledge, Anxiety, and Post-Purchase Dissonance is necessary to be discussed further. This research attempt to use two-stage panel study and survey consumers who purchase in the 3C and home appliances stores located in North Taiwan. Besides, this research conducted convenience sampling and collected 185 valid questionnaires. The empirical results using Hierarchical Regression Analysis find that State Anxiety and Trait Anxiety significantly and positively influence on Post-Purchase Dissonance and Trait Anxiety moderates the relationship between State Anxiety and Post-Purchase Dissonance. In addition, through Simple Regression and Multiple Regression we find that Product Knowledge significantly and negatively influences on Post-Purchase Dissonance and State Anxiety, moreover, State Anxiety is a full mediated variable between Product Knowledge and Post-Purchase Dissonance. Finally, Purcahse-Decision Involvement significantly and positively influences on Post-Purchase Dissonance, and Perceived Value and Brand Awareness of product significantly and negatively influence on Post-Purchase Dissonance.