Implicit or Explicit: Literature Review and Prospects of Research on the Effects of Advertising Metaphors

Metaphorical advertisements are those mainly relying on the usage of metaphors to deliver the advertising appeal. They are contrasted to non-metaphorical advertisements in which the advertising appeal is expressed in a straightforward and explicit way. When compared with their non-metaphorical counterparts, metaphorical advertisements are mainly featured with the indirectness of persuasion because the advertising appeal of them is implicitly presented with metaphors which should be understood at first to know what the advertisements are saying.　　Previous research finds that metaphorical advertisements are widely and persuasively used by advertisers, and they can be separated into rich types from different perspectives. For example, metaphorical advertisements can be divided into two categories based on the advertising elements in which the metaphor appears（i.e., the representational modality of metaphors）and they are visual metaphorical advertisements and pictorial metaphorical advertisements respectively; according to the degree of the direct comparison between the target domain（i.e., advertising products or services）and the source domain（i.e., the object that an advertising product or service is compared as）within a metaphor, metaphorical advertisements can be categorized as concrete metaphorical advertisements and abstract metaphorical advertisements; according to how the source domain and target domain of metaphors are visually presented, metaphorical advertisements, in particular, the pictorial metaphorical advertisements can be separated into three categories, i.e., scenario metaphors, mixed metaphors, and pictorial similes.　　In view of the universality and diversity of metaphors in advertising practice, scholars have a keen interest in evaluating the effects of metaphorical advertisements, and their research mainly focuses on the communication effects and social effects of advertising metaphors. In terms of the communication effects, metaphorical advertisements can make a significant influence on consumers’ cognition and emotion in comparison with non-metaphorical advertisements. Among them, the cognitive effect is mainly reflected on the number of elaborations while the emotional effect on the pleasure. It is noteworthy that both the cognitive and emotional effects are caused by metaphor comprehension, and the positive effects generated by the two effects can further enhance the persuasiveness of the whole advertisement. In terms of the social effects, metaphorical advertisements are viewed by advertisers as an important tool for changing or constructing consumers’ perceptions when compared to non-metaphorical advertisements that directly state the advertisement appeal, because the metaphor is not only a rhetorical device but also one of the most important thinking mechanisms of human beings.　　Although metaphorical advertisements can have positive effects in many aspects compared to their non-metaphor counterparts, this does not mean that the use of metaphors in advertising is definitely effective. The reason lies in that the effects of advertising metaphors can also be affected by many other factors which can be classified into two categories, i.e., factors relevant to the advertisements and factors related to the consumers. According to previous studies, the influencing factors related to the advertisements can be further divided into three categories: the type of metaphorical advertisements, the product type, and the degree of verbal anchoring. Among the factors related to consumers, scholars pay more attention to how the differences in need for cognition（NFC）, processing capabilities, and cultural backgrounds affect the effectiveness of advertising metaphors.　　By reviewing previous studies in this field, we find that although research on the effectiveness of metaphorical advertisements has made a lot of achievements, there is still space for further exploration and improvement. This article finally discusses the directions for future research from the following three aspects: the research perspective, the research object, and the research technique.