This research analyses the effects of endorsers’ beardedness (i.e., the state of being bearded) on their perceived credibility and consumers’ purchase intention for various categories of products. According to Ohanian (1990), credibility is a construct with three sub-dimensions: attractiveness, the degree to which the source’s physical appearance and/or its perceived personality is appealing; expertise, the extent to which the communicator is perceived as a source of valid assertions; and trustworthiness, the degree of confidence aroused in perceivers. Recent research has demonstrated the possibility of associating the three sub-dimensions of credibility with different categories of products, depending on whether these latter ones possess specific characteristics that are congruent with one or another sub-dimension. In line with this approach, results show that bearded endorsers are perceived to be more credible and to have a positive influence on purchase intention, but these effects occur only in relation to specific kinds of advertised products. Theoretical and operational implications for communication strategies are discussed.
Source: “Beardedness in advertising: effects on endorsers’ credibility and purchase intention” from Journal of Marketing Communications
So what were those products? The Chronicle of Higher Education has the answer:
...Participants thought the men with beards had greater expertise and were significantly more trustworthy when they were endorsing products like cell phones and toothpaste.
But, oddly, men with beards were slightly less effective than smooth-cheeked fellows in underwear advertisements. Apparently we don’t want Zach Galifianakis selling us boxers.
Is this just limited to endorsers? Maybe not:
The researchers say the implications of their findings could extend far beyond advertisements. For instance, male politicians might want to consider not shaving because the “presence of a beard on the face of candidates could boost their charisma, reliability, and above all their expertise as perceived by voters, with positive effects on voting intention.”
Important note: The study looked only at neat, medium-length beards. You can’t just go all ZZ Top and expect people to trust you.