Attractiveness or gravitas?

From Effects of Instructor Attractiveness on Learning by Richard Westfall, Murray Millar & Mandy Walsh

It's psychology research so caveat lector.

From the abstract:

Although a considerable body of research has examined the impact of student attractiveness on instructors, little attention has been given to the influence of instructor attractiveness on students. This study tested the hypothesis that persons would perform significantly better on a learning task when they perceived their instructor to be high in physical attractiveness. To test the hypothesis, participants listened to an audio lecture while viewing a photograph of instructor. The photograph depicted either a physically attractive instructor or a less attractive instructor. Following the lecture, participants completed a forced choice recognition task covering material from the lecture. Consistent with the predictions; attractive instructors were associated with more learning. Finally, we replicated previous findings demonstrating the role attractiveness plays in person perception.

I wonder if it is attractiveness per se, which I believe is quite conceivable, or whether it might not be fastidiousness. What I mean by that is whether people's assessment of attractiveness might be influenced by how the person is presented - not just their features but how they are dressed, etc. The old adage is that the clothes makes the man and I could conceive of a mechanism that delivers the above results not based on attractiveness but on perceived seriousness.

In other words, an unkempt slovenly person comes in to lecture. Are you going to accord them the seriousness that their expertise might deserve? I suspect not.

Alternatively, someone comes in dressed as a professional and presents themselves confidently. Do you take them more seriously and up your attentiveness game? I don't know but I suspect that the above results might be tied to that mechanism of gravitas signaling over simply attractiveness.