We tend take preferences as given and constant, but there is mounting evidence that preferences change over the life cycle and over external circumstances, as I reported before. There may now even evidence that preferences that preferences follow a predictable cycle, at least for women.
Matthew Pearson and Burkhard Schipper asked an unusual question to the female participants in an otherwise standard auction experiment: what stage of your menstrual cycle are you in? It turns out the answer can explain bidding behavior: while otherwise indistinguishable from men, women in their menstrual and premenstrual phase bid significantly higher, thus exhibiting more risk taking. Pearson and Schipper argue this can be explained by biology and evolution. This is when women are most likely to be fertile and take risks to increase the probability to procreate.
The experiment is not entirely clean, it would be preferable to have the same women participate repeatedly during a menstrual cycle, but even this indirect evidence is intriguing. And it should tell women to take their cycle into consideration when taking decisions.