What is it that is difficult to detect in a person and still people care about potential partners having it? Income? (But I don't get the impression that the typical PUA is poverty-stricken, and I can't think of reasons for people to care about that in very-short-term relationships, which AFAIK are those most PUAs are after.) Lack of STDs? (But, if anything, I'd expect that to anticorrelate with alpha behaviour.) Penis size? (But why would that correlate with behaviour at all?)
What is it that is difficult to detect in a person and still people care about potential partners having it?
I guess it is how the person will behave in the future, and in exceptional situations. We can predict it based on person's behavior here and now, unless that behavior is faked to confuse our algorithms.
Humans are not automatically strategic and nature is not antropomorphic, but if I tried to translate the nature's concerns for "I want an alpha male", it would be: "I want to be sure my partner will be able to protect me and our child...
If it's worth saying, but not worth its own post, even in Discussion, it goes here.