Are they selling underwear or the male model with six packs abs?

They are definitely utilizing subliminal programming to their advantage, a programming that plays on the psyche of our most basic intrinsic functions. The same applies for Victoria Secret models. Sex sells because it's an ingrained part of being human, couple that with our competitive nature and you will get six packs and curvaceous ads.

The mere fact that your brain deviated to a visual representation of an alpha male is a fine example of what we're talking about here to begin with.

In terms of how the professor describes this theory, you've just exhibited fitness payoff identifiers.

Thank you for the tip! :)