名聞遐邇抑或惡名昭彰 探討網路口碑正負性影響知覺助益程度

Abstract

兩派對立文獻分別證實：比起負面口碑，消費者對正面口碑有更強烈的知覺助益程度，即為「正面效應（positivity effect）」；而相較於正面口碑，消費者對負面口碑的知覺助益程度更為強烈，即為「負面效應（negativity effect）」。過往學者們對於該二效應各執一詞，因而本研究欲排解雙方之分歧，探討何種因素干擾口碑正負性對知覺助益程度的影響，並提出相關推論：首先，以「確認偏誤（confirmation bias）」作為理論基礎，提出正面效應與負面效應的存在取決於消費者對產品品牌之印象。換言之，可靠的品牌可增加正面口碑的知覺助益程度，並抑制負面口碑之影響，亦即正面效應；而不可靠的品牌卻加強了負面口碑的知覺助益程度，同時削弱正面口碑之作用，亦即負面效應。其次，依消費者不時對網路口碑探本溯源，本研究假設消費者會先將口碑的正負性歸因於產品品質或評論者偏好，進而決定口碑的助益程度。然而，因消費者對於產品種類之預期亦會影響歸因，故本研究同樣以確認偏誤為推理基礎，預測炫耀性商品將促使消費者傾向對正面口碑做出產品歸因、對負面口碑歸做出評論者歸因，產生正面效應；而因對非炫耀性商品無所預期故不會影響歸因過程。再者，因消費者的歸因與知覺助益程度受「自我構念（self-construal）」影響，本研究認為：相較於互依我（interdependent）的消費者，產品歸因程度與知覺助益程度的正相關在獨立我（independent）的消費者中更加明顯。最後，以上所有假說皆由實驗順利驗證；本研究調和正面效應與負面效應的爭議，也重述建立品牌形象之重要性。

Two conflicting theories document the effects of eWOM valence (positive or negative) on consumer perceived helpfulness: Positivity effect shows that positive reviews are considered as more helpful over negative reviews, while negativity effect shows the contrary. Adopting the theory of confirmation bias, this research proposes that both effects coexist contingent upon consumers’ existing beliefs of the brand reputation. Specifically, dependable brands bolster the perceived helpfulness of positive reviews and dampen that of negative reviews (positivity effect). In contrast, undependable brands strengthen the perceived helpfulness of negative reviews and weaken that of positive reviews (negativity effect). While this may be true, consumers do not always take the eWOM valence at face value. We posit that consumers attribute the eWOM valence to either product quality, or reviewer preferences, as an antecedent to determine review helpfulness. Nevertheless, prior beliefs of a product type’s superiority can affect attribution. We infer that positional products facilitate consumers to attribute the cause of positive reviews to the product, and negative reviews to the reviewer (positivity effect). On the contrary, consumers lack prior beliefs on non-positional products; hence, confirmation bias does not sway the attribution process. Meanwhile, consumers’ self-construal affects their judgments of attribution. We propose that there is a stronger positive correlation between product-related attribution and perceived helpfulness for independent individuals than interdependent individuals. The empirical results of this research support all hypotheses. This research reconciles the dispute between positivity and negativity effects and reinforces the importance of brand image.