If anything, this weakens the researcher’s argument. It implies the ability to identify dominant individuals through pictures doesn’t extend to all primates—which suggests something other than primate biology is at play.

This is irrelevant. The researcher concludes primate biology allows humans to identify other extroverted humans—she makes no claim about other personality traits.

This strengthens the researcher’s assumption that people are able to identify extroverted humans and dominant chimpanzees for the same reason. It implies humans in both cases are identifying genetically assertive individuals.

This is irrelevant. It doesn’t change the fact that humans and chimpanzees are both primates, and the researcher credits primate biology—not a recent-ancestor relationship—for humans’ ability to identify extroverts.

If anything, this weakens the argument. It raises the possibility that humans aren’t actually that good at identifying extroverts among pictures of real people.