Jeneba, do you know what other questions were asked in the study? Were these people even asked why they had a specific preference? It appears as though the question of preference was asked, but nothing useful beyond it. They seem only to take the opportunity to inject that “social exchange theory” as an explanation (aka, making sure the answer fits a preferred theory). If so, it is then a very flawed study. Personally, I hope it is a flawed study, rather than a character flaw of the participants.