The participants then assessed the degree of matchup between the celebrities and the products and expressed their attitudes toward the brands. The results showed that when a brand matched up with its celebrity endorser’s traits — and when consumers were paying close attention — the brand wasn’t harmed by the fact that its spokesperson endorsed other products. But highly involved consumers who perceive low congruence (as in Vin Diesel pitching an expensive watch amid sophisticated imagery and wording) became significantly more negative as the number of brands the celebrity endorsed grew.
When consumers weren’t scrutinizing an ad, however, the product fit wasn’t as much of a concern, and their attitude simply became more negative as the number of products endorsed by a single celebrity increased. In other words, with little time to evaluate an ad, consumers fixated on how many brands were endorsed rather than weighing whether the fit was persuasive.
In the second experiment, the researchers used 383 participants to explore the effect of several endorsers on one brand, by having the Castolano watches endorsed by either one or three spokespeople. The researchers placed celebrities associated with sophistication (Brosnan, Anthony Hopkins, and Sean Connery) and ruggedness (Diesel, Sylvester Stallone, and Dwayne “The Rock” Johnson) into ads stressing either the elegance or the toughness of the brand.
Half of the participants saw ads with only Brosnan or Johnson, and the remaining subjects viewed three ads with a different celebrity in each; again, participants were further separated into high- and low-involvement scenarios.
When participants carefully evaluated an ad, the marriage of brand and celebrity personality was key. The participants became more positive about the brand as more celebrities endorsed it and were perceived as a good fit, and grew increasingly negative as more inappropriate spokespeople joined the campaign.
Notably, however, the authors found no evidence in a low-involvement context that an increase in the number of endorsers with little relationship to the brand damaged consumer attitudes. In fact, when consumers were not scrutinizing the ads too heavily, their attitude toward the brand became more positive as the number of endorsers increased.
The authors argue that this could be because the mere number of endorsers had a positive influence when consumers weren’t paying close attention. Without a more thorough examination of the brand–celebrity relationship, consumers relied on peripheral clues (in this case, reasoning that the greater the number of people who like it, the better it must be).
In terms of practical application, the authors note that when ads can be carefully evaluated by consumers, a celebrity who endorses several products can damage a brand only when there is a poor fit with the other brands in his or her portfolio. “If managers are confident that ads will be viewed under high involvement,” they write, “then the fit of other brands endorsed is more important than whether other brands are endorsed at all.”
But when ads are going to be viewed under more transient conditions, managers might be best served by hiring as many exclusive endorsers as they can, with no particular regard to their “marriage” with the brand.
Consumers respond differently to marketing campaigns that use multiple celebrities, depending on whether they are viewing the ads in a peripheral or highly involved context. If the context is peripheral, consumer response becomes more positive as the number of endorsers increases, so long as the endorsers aren’t backing a lot of other brands as well. If the context is more focused, the endorser’s fit with the brand is crucial, as is the fit that the endorser has with any other brands.