消費者通常在不完全資訊的情況下作選擇，過去的研究論證在不完全資訊的情況下，消費者將對選項間的共同屬性(定義為選擇集中的所有選項均有已知屬性值的特定屬性)賦予較高的權重，基於此觀念，Kivetz 及 Simonson (2000)論證在不完全資訊下將觀察到偏好非遞移 (preference intransitivity) 的現象 (A>B 且 B>C，但 A<C)。對立於過去的研究，目前的研究建立在產品知識水準將影響資訊處理方式的相關文獻，並導入尺度等價的觀念，透過五個實驗論證在不完全資訊的情況下，消費者的產品知識水準及屬性平衡選項(定義為特定選項的已知屬性值相等)是否存在於選擇集中將影響消費者對於選擇集中選項的偏好。 實驗一論證在不完全資訊下，消費者對於選擇集中選項的偏好係消費者知識的函數，基於高知識消費者傾向採用以品牌為基礎的處理方式，而低知識消費者傾向採用以屬性為基礎的處理方式的推論。高知識的消費者將選擇一個已知屬性值在市場屬性水準範圍內績效表現較平均的選項(相對於一個已知屬性值表現較佳、另一個表現較差的選項)，即使該選項在共同屬性的績效表現較差；而低知識的消費者則傾向選擇共同屬性表現較佳的選項。實驗二則導入方案聯合及分離兩種不同的評估模式，論證高知識消費者採用兩種評估模式對於選項偏好的差異將小於低知識的消費者。實驗三探討消費者知識水準及具有共同屬性值的類別參考資訊對於在不完全資訊下選擇不作選擇選項比例的交互影響，我們論證低知識消費者在面對類別參考選項的共同屬性值優於及劣於選擇集中選項的共同屬性值的兩種情況下，選擇不作選擇選項比例的差異將大於高知識消費者。實驗四則導入尺度等價的觀念，將所有屬性的市場屬性水準範圍標準化成相同的尺度範圍，藉以將消費者對於市場屬性水準範圍的知識提昇到同一水準，論證當選擇集中不存在屬性平衡選項時，消費者對於選項的偏好是由共同屬性所決定，然而當選擇集中存在屬性平衡選項時，消費者將偏愛屬性平衡選項，即使該選項在共同屬性上的表現較差。實驗五則更進一步探討屬性平衡選項的存在對於是否能夠觀察到偏好非遞移現象的影響，我們論證當選擇集中的三個方案中均不存在屬性平衡選項時，將可以觀察到偏好非遞移的現象，但當三個方案中有一個方案為屬性平衡選項時，偏好非遞移的現象將不會被觀察到，且屬性平衡選項將支配選擇集中的其他選項，目前的研究並根據研究結果進行理論及實務意涵的討論。 Consumers often need to make choices based on incomplete information. Previous research has argued that consumers will place more weights on the common attribute (defined as the specific attribute values of all options are known) between options in the case of incomplete information. Kivetz and Simonson (2000) demonstrated that a common dimension may lead to intransitive preference (A>B, B>C, but A<C). Contrary to previous research, the present research employed five studies to explore the influence of the levels of consumer knowledge and attribute balance option (when known attribute values of specific option are equal) presented in the choice set on consumer preference when information is incomplete. Study 1 demonstrated that consumer preference toward the options in a choice set is a function of consumer knowledge. Base on the inferences to a high-knowledge consumer will more possibly to adopt brand-based processing, whereas a low-knowledge consumer will more possibly to adopt attribute-based processing. A high-knowledge consumer would choose an option whose known attribute performance is fairly average in the attribute range in the marketplace (when compared to an option with mixed known attribute values), even when that the option performance in common attribute is relatively poor. A low-knowledge consumer, on the other hand, would tend to choose an option that has better performance in the common attribute. Study 2 introduced two different evaluation modes of joint evaluation and separate evaluation, demonstrated that the preference differences in high-knowledge consumers’ application of both joint (choose from two simultaneously presented options) and separate (present and evaluate one option one by one) evaluation modes are smaller than those in low-knowledge consumers. Study 3 explored the interaction effect of consumer knowledge and category reference with common attribute value on choice deferral under incomplete information, demonstrated that the proportional differences among low-knowledge consumers in choosing no-choice option when facing with two conditions of either common attribute of the category reference being better or worse than the common attribute of the options in a choice set will be greater than those in high-knowledge consumers. Furthermore, we introduced the concept of scale equivalence in Study 4 and 5. Study 4 demonstrated that when attribute balance is unavailable in both options, consumers will prefer the option whose common attribute performs better; in contrast, when attribute-balance is available in one option, consumers will prefer the option with attribute-balance even the common attribute performs worse. Study 5 explored the presence of attribute balance would prevent consumers from exhibiting preference intransitivity. We demonstrated that when attribute balance is unavailable in the three options, intransitivity will be observed. In contrast, when any one of the three options includes an attribute balance, intransitivity will not be observed and the attribute balance option will dominate the other options in the choice set. The present research also conducted discussions regarding theoretical and practical implications based on the research results.
