Modeling two effects of superlative expressions in eWOM messages on consumer evaluative inferences

Electronic word-of-mouth (eWOM) is an important information source that influence consumer product evaluations. The author previously developed a computational model, called an inference space model, that predicts potency-magnitude relations of eWOM messages involving subjective rank expressions, which refer to the linguistic representations related to the attitude-levels of the benefit of product attributes. This paper focuses on superlative type messages and proposes two effects of eWOM messages on message-receiver's evaluative inferences: a comparison set effect and a difference degree effect. A model and the interpretation of superlative type messages are developed as the basis for formalizing and parameterizing the two effects. This paper considers four groups of message-classes, which are naturally generated from the perspective of the presence or absence of the two effects, to investigate potency-magnitude relations. The investigations include the development of a Q-magnitude Relation Map (Q-Map) that illustrates how the relations change based on the values of two evaluation parameters: evaluation target size and evaluation scale size. The results show that (1) Q-magnitude relations rarely depend on the evaluation parameters and (2) the two effects may be canceled to make the relations indeterminate.