Given the prevalence of imagery appeals in today's marketplace, the current research studies the role of mental imagery in how consumers process and react to advertisements with different numbers of ad claims. Past research has proposed "three" as the magical number of ad claims that maximizes persuasion, with more than three ad claims increasing skepticism and reducing evaluation. In the current research, we replicate this socalled "charm of three" effect, but only when consumers do not engage in mental imagery; when they do, however, we find that the effect is moderated, in that more ad claims beyond three produces more favorable product evaluation. Additionally, we provide evidence that the moderating effect of mental imagery is driven by transportation and skepticism toward the ad claims, with mental imagery increasing transportation and decreasing skepticism when there are more than three ad claims. Our research contributes to a better understanding of the "charm of three" effect, its boundary conditions, and underlying mechanism.
Keywords Charm of three; Ad claims; Mental imagery; PersuasionMany ads contain more than one claim about the advertised product. For example, Oral-B's Glide touts "5 benefits; 1 floss: micro-textured floss helps protect against plague; gingivitis; cavities; odor-causing bacteria; and surface stain between teeth." Conventional wisdom suggests that if more positive claims are included, more compelling value propositions are delivered to consumers. This is consistent with the "set-size effect" that impressions about an ad and the advertised product increase with more positive claims (Anderson, 1967). This may explain why firms bombard consumers with a variety of product information in TV commercials, on billboards, in flyers, on websites, and in pop-up ads.