"Therefore, multiple lines of evidence suggest that mating motives play a more important role in driving financial and pro social biases toward attractive adults than previously recognized." (Maestripieri, Henry & Nickels, 2017)

Abstract:

Financial and pro social biases in favor of attractive adults have been documented in the labor market, in social transactions in everyday life, and in studies involving experimental economic games. According to the taste-based discrimination model developed by economists, attractiveness-related financial and pro social biases are the result of preferences or prejudices similar to those displayed toward members of a particular sex, racial, ethnic, or religious group. Other explanations proposed by economists and social psychologists maintain that attractiveness is a marker of personality, intelligence, trustworthiness, professional competence, or productivity.

Evolutionary psychologists have argued that attractive adults are favored because they are preferred sexual partners. Evidence that stereotypes about attractive people are causally related to financial or pro social biases toward them is weak or nonexistent.

Consistent with evolutionary explanations, biases in favor of attractive women appear to be more consistent or stronger than those in favor of attractive men, and biases are more consistently reported in interactions between opposite-sex than same-sex individuals. Evolutionary explanations also account for increased pro social behavior in situations in which attractive individuals are simply bystanders.

Finally, evolutionary explanations are consistent with the psychological, physiological, and behavioral changes that occur when individuals are exposed to potential mates, which facilitate the expression of courtship behavior and increase the probability of occurrence of mating. Therefore, multiple lines of evidence suggest that mating motives play a more important role in driving financial and pro social biases toward attractive adults than previously recognized.

This was quite a controversial conclusion by the authors of this paper, with them strongly arguing for the primacy of biologically driven, mating relating evolutionary motives ultimately being the main source of the the myriad (seemingly not directly related to mating) social and economic benefits accrued by the physically attractive.

See LaFrance & Eagly (2017) for a dissenting view of the authors conclusions: https://doi.org/10.1017/S0140525X16000522

Also, the other studies referenced by the authors constitute a veritable treasure-trove of blackpills themselves.