本研究主要以背景效果的理論為基礎，在前後廣告不同的品牌關係下，探討兩者訴求一致性的高低，如何使前置廣告對受試者評價後置廣告時所產生的影響效果出現差異，並以後置廣告訊息類別與受試者產品知識為調節變數，進一步探討這兩者如何增強或削弱前述背景效果的強度。 經由前測選出數位相機和洗面乳為正式實驗題材，兩個產品類別的前置廣告品牌分別是SONY和DOVE，訴求焦點分別是「專業型相機」和「滋潤保濕效果佳」；而兩產品後置廣告的副品牌分別是SONY-Master和DOVE-Scent，虛擬品牌分別是DigiXpert和AROMA。兩產品後置廣告訴求焦點，在與前置廣告訴求具高一致性者分別是「鏡頭品質」、「畫素高」、「含有甘油成分」、「洗後不緊繃」，在與前置廣告訴求具低一致性者分別是「預設模式多」、「價格便宜」、「含有水楊酸配方」、「超強洗淨力」。根據上述前測結果，設計出一個2(訴求一致性：高與低)×2(訊息類別：深層訊息與表層訊息)×2(產品知識：高與低)的實驗，並以政大大學部學生為樣本，回收984份有效問卷進行統計分析。 研究結果顯示，當後置廣告之品牌為一虛擬品牌時，不論是在數位相機或是洗面乳產品，均證實當後置廣告訴求與前置廣告訴求具有高度一致性時，受試者對後置廣告的產品評價，會受到前置廣告主要訴求的影響，使其評價在該訴求點上展現出同化效果；當後置廣告訴求與前置廣告訴求具有低度一致性時，受試者對後置廣告的產品評價，則會受到前置廣告主要訴求的影響，使其評價在該訴求點上產生對比效果。當後置廣告之品牌為前置廣告品牌之副品牌時，也得到類似的結果，除了在洗面乳產品/訴求一致性高的情境下，受試者對副品牌後置廣告的評價的確展現出預期的對比效果，與受試者對虛擬品牌後置廣告在相同情境下的評價有所差異，與本研究預期相符；其他情境出現的背景效果種類均與受試者對虛擬品牌後置廣告在相同情境下的評價類似，而與本研究預期不符。 整體而言，本研究結果提醒廣告主除了廣告本身的內容之外，廣告所處溝通環境中的其他廣告也會對廣告效果產生相當的影響作用，尤其對於P＆G、J＆J、Unilever等擁有眾多產品品牌的大型公司來說，當它們對媒體進行聯合採購時，等於對廣告的背景環境有了部分的掌握能力，更應該善用這樣的優勢，妥善安排廣告順序，以提昇廣告效果、或避免廣告品牌間自相殘殺。除此之外，根據目標受眾的產品知識調整廣告訊息的呈現方式，也可以適度的改變上述效果的強度。 / The purpose of this study is to investigate the contextual effects the former ad will exert on the evaluation of the latter ad, under different consistency of appeals and branding strategies between these two ads. Moreover, the message type in the latter ad and the product knowledge of the participants are also discussed to understand how they could moderate the above assimilation or contrast effects. Digital camera and facial cleanser are selected as the test product categories. In the digital camera category, SONY was chosen as the brand of the former ad. SONY-Master (sub-brand condition) and DigiXpert (virtual brand condition) were the brands of the latter ads. In the facial cleanser category, DOVE was chosen as the brand of the former ad. DOVE-Scent and AROMA were the brands of the latter ads. A 2 (appeal consistency: high versus low)×2 (message type: deep cue versus surface cue)×2 (product knowledge: high versus low) factorial experimental design was applied on 984 college student samples. The main effect of the appeal consistency suggested that when the latter ad carried the virtual brand and under the condition of high appeal consistency between two ads, participants’ evaluation of the latter ad on the dimension of the former ad appeal showed an assimilation effect. On the other hand, participants’ evaluation of latter ad on the dimension of the former ad appeal, under the condition of low appeal consistency between two ads and with a virtual brand, revealed a contrast effect. The above effects occurred in both product categories. When product in the latter ad used a sub-brand strategy, participants’ evaluations of the latter ad on the dimension of former ad appeal were similar to those when the latter ad carried the virtual brand. The only exception was the high appeal consistency condition in facial cleanser category, under which participants’ evaluations revealed a contrast effect. In general, this study suggests the advertisers who have multiple brands, such as P&G, pay attention to the contexts of ads. With their powerful bundle media purchase, they are granted with more influence over the contexts. Marketers should take this advantage to enhance ad effects or avoid mutual damage between brands. Finally, advertisers could also adjust the message type of the ad appeal according to the product knowledge of consumers to moderate the above contextual effects.