Abstract:  Marketing practice has recently seen an increasing number of ads featuring more than one celebrity endorser in one ad. Although many studies have been conducted to investigate the effect of endorsement, little research attention has been given to group endorsement and hardly any studies have focused on the relationships between endorsers (cooperative vs. conflicting) in one ad. Building on the studies about advertising effectiveness and conflict, the current research proposes that the conflicting group endorsement brought stronger advertising effectiveness than the cooperative one. The mediating effect of consumers’ perceived vividness of the ad and the moderating effects of consumers’ affect intensity and the degree of discrepancy between endorsers were also examined. Two pretests and three main experiments were conducted to test the proposed hypotheses. Following the methods in previous studies, three products matching up with the two endorsers used in this study were screened in Pretest 1. The validity of the manipulation of endorsers’ relationship types were verified in Pretest 2. In Experiment 1, a one factor (endorsers’ relationship type: cooperative vs. conflicting) between subjects design with 99 participants was adopted to examine the effect of endorsers’ relationship types on advertising effectiveness and the mediating effect of consumers’ perceived vividness. The descriptions of product, endorsers and their relationship types verified in the pretests were used and advertising effectiveness and perceived vividness were measured by established scales. Following a similar procedure, a 2 (endorsers’ relationship type: cooperative vs. conflicting) × 2(affect intensity: high and low) between subjects design with 91 participants was adopted to examine the moderating effect of consumers’ affect intensity in Experiment 2. The participants’ affect intensity were measured by established scales and divided into two groups by the median. In Experiment 3, a 2 (endorsers’ relationship type: cooperative vs. conflicting) × 2(degree of the discrepancy between endorsers: high and low) between subjects design with 102 participants was adopted to examine the moderating effect of the degree of discrepancy between endorsers. The participants were asked to rate the two endorsers based on three attributes and they were further divided into two groups by the median of the absolute value of the difference. The results revealed that, compared to the cooperative group endorsement, the conflicting group endorsement had positive impact on advertising effectiveness. This effect was mediated by consumers’ perceived vividness of the ad. Furthermore, consumers’ affect intensity moderated this effect. For consumers with higher affect intensity, the conflicting group endorsement promoted advertising effectiveness, but this effect did not happen for the consumers with lower affect intensity. The degree of discrepancy between endorsers also moderated this effect. When the discrepancy of consumers’ evaluations of the endorsers in the group endorsement was small, the conflicting group endorsement had a positive effect on advertising effectiveness, but this effect did not happen when the discrepancy is large. The current research provided empirical evidence to the influence of endorsers’ relationship types in group endorsement on advertising effectiveness and its underlying process. This study expanded the research of advertising effectiveness from the perspective of endorsers’ relationship type. The results reflected the positive role of conflict and verified the effect of vividness, and also highlighted the importance of consumers’ and endorsers’ properties. Moreover, these findings provided meaningful marketing implications for practical ad design and helped a brand to choose proper endorsers in group endorsement.

Key words:  endorsers&rsquo, relationship type, vividness, advertising effectiveness, affect intensity, degree of the discrepancy between endorsers