A recent review published in Philosophical Transactions of the Royal Society B argues that women are catty and gossipy because of evolution. It was likely dreamt up in the twilight hours, after its author watched the mall safari scene of Mean Girls and thought, "I wonder...."
The paper, which was authored by Tracy Vaillancourt of University of Ottawa, argues that "females prefer to use indirect aggression over direct aggression (i.e. verbal and physical aggression) because this form of aggression maximizes the harm inflicted on the victim while minimizing the personal danger involved." She cites a study by Anne Campbell that finds that females across several species tend to engage in indirect aggression when competing for mates because direct aggression is too potentially costly: if a female is injured or killed, it's likely her offspring will die as well.
Vaillancourt further argues that "females punish other females who seem to make sex too readily available using indirect aggression," by devaluing them in a "concealed way which diminishes the risk of counterattack." In the last sentence of her conclusion, she links this hypothesis to evolution:
[T]he benefits of using indirect aggression seem clear — fewer competitors and greater access to preferred mates, which in ancestral times would have been linked to differential reproduction rates, the driving force of evolution by sexual selection.
Hmm, okay. It's a big leap to go from "women tend to engage in indirect aggression now" to "women engaged in indirect aggression at some distant point in our evolutionary past." And, as Campbell points out to LiveScience, "There is virtually no sex difference in indirect aggression. By the time you get to adulthood, particularly in work situations, men use this too." Furthermore, the review doesn't really prove that indirect aggression works — just that it exists. Says Kim Wallen, a psychologist at Emory University, "Sadly, no empirical data are ever presented that are relevant to the central claim."
Slut-shaming: probably not hard-wired into our DNA. The first cave-paintings were likely not code for "LUCY IS A BIG WHORE." Carry on, everyone.