本研究以二元訊息處理理論(ELM and HSM)和勸服變數的多重角色(Multiple role)為基礎，探討在不同的涉入程度及訊息來源(雜誌)與產品種類相關性下，訊息來源可信度如何影響消費者的產品態度。針對226位學生樣本進行實驗設計，研究結果發現，高涉入的受測者，當訊息來源與產品種類高相關時，其產品態度會受到訊息來源可信度的影響；但是當訊息來源與產品種類低相關時，則不會受到訊息來源可信度的影響。而低涉入的受測者，不論訊息來源與產品種類相關與否，高可信度的訊息來源都會產生較正面的產品態度。

This study, applies dual-process theories, especially the perspective of multiple-roles for persuasion variables, to explain how consumer's product attitudes are affected by source credibility under different consumer involvement and source-product relevance conditions. The result showed that in the high involvement and high source-product relevance condition, participants who were exposed to product information from high-credibility source generated more favorable product attitudes than those who were exposed to product information from low-credibility source; however, in low source-product relevance condition, source credibility doesn't have any impact on product attitudes. In addition, under low involvement condition, regardless of source-product relevance, higher-credibility source induced more positive product attitudes.