群體決策應用於消費行為領域的相關研究如鳳毛麟角，主要因原在於群體決策過程及成員間的互動不易觀察，但放眼實體與虛擬網路的交易情境中，個體消費者行為與群體決策結果相互影響的實例卻顯而易見，例如：線上集體購物，消費者藉由網路平台集結彼此之力量以獲取較優惠的價格，並且於集體購買過程中受他人留言訊息影響而產生群體決策中的群體極端化(group polarization)與資訊性從眾(information conformity)行為。
本研究以虛擬網路環境中的群體決策行為為其切入點，並進一步探討線上集體購物平台中口耳相傳所傳達的訊息特性，對個別買家形成的態度及群體決策行為的影響。本研究採行巢式三因子實驗設計，三因子分別為訊息數量(多vs 少)、訊息論點(強vs 弱)及訊息方向性(正向vs負向)，探討三個自變項對線上集體購物群體決策行為的影響效果。
研究結果發現，網路口耳相傳訊息方向性對說服效果具主導性(dominate)影響，且再探討本研究另兩個自變項訊息數量與訊息方向性時，則顯著形成集體購物的資訊性從眾與群體極端化行為，反之，當留言板中只提供訊息數量或訊息論點之留言時，因訊息方向性主導效果影響，促使訊息留言無法對消費者造成訊息說服效果，而無法提高消費者的購買意願。本研究結果將於實務上提供網路業者瞭解消費者於線上集體購物行為與作為線上集體購物機制設計之參考依據。

Because of an invisible interaction process between group members, the related research about group decision on the consumer behavior was rare. However, no matter in real entity or virtual network environment, individual behavior is influenced exactly on the result of group decision, for example, on-line group buying. Consumer would permeate online trading platform to concertrate each other’s power to draw better price and on this process consumer would be influenced by other buyers purchase experience and accrued group polarization and information conformity of group decision.
This thesis according to group decision behavior of virtual network environment and further trated as the WOM on Web affect individual buyer’s attitude and group decision behavior of online group buying. The nested factor design manipulates the three independent variables of number of messages, the magnitude of argument, valence to study investigated three independents variables to affect group decision behavior of online group buying.
The results find that valence dominate persuasion effect and treated independent variables of number of messages that detected interaction of number of messages and valence could significantly become information conformity and group polarization of on-line group buying. On the other hand, because of valence domination when bulletin board system just provided number of messages and the magnitude of argument that wouldn’t make consumer produce persuasion effect and enhance purchase intention. This study result will provide consumer behavior of group buying for network operators in real-life and regard as network operators design consultation of group buying mechanism.

目錄
摘 要 I
Thesis Abstract II
致謝辭 III
目錄 IV
表目錄 VI
圖目錄 VII
第一章 緒論 1
第一節 研究背景與動機 1
第二節 研究目的 5
第三節 研究流程與方法 6
第二章 文獻探討 8
第一節 線上集體購物現況 8
第二節 線上集體購物群體決策 9
第三節 網路口耳相傳訊息說服效果 11
第四節 網路口耳相傳訊息特性對訊息說服效果之影響 13
第五節 訊息說服效果對群體決策行為之影響 16
第三章 研究方法 20
第一節 研究架構與研究假設建立 20
第二節 實驗架構 23
第三節 預試實驗設計與預試結果分析 25
第四節 變數定義與操作 29
第五節 實驗建構及流程與問卷設計 34
第六節 資料分析方法 42
第四章 資料分析結果 43
第一節 敘述性統計分析 44
第二節 信度分析 45
第三節 研究假設驗證 47
第四節 研究檢定總整理 65
第五章 研究結論與建議 66
第一節 研究結論 66
第二節 行銷理論意涵 69
第三節 實務建議 71
第四節 研究限制與未來研究方向 73
參考文獻 76
附錄 1預試問卷(1) 80
附錄2 預試問卷(2) 81
附錄3 研究問卷 84
附錄4 實驗網站介紹 85

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