They is a widespread belief that women are more generous, and this is due to their maternal instincts. Experimental evidence confirms that women are indeed more generous, but has not been able to explain why. An interesting question here is whether by more generous in innate or whether it cost with the social context. This seems difficult to measure, but one could try to devise experiments that can get a hint of an answer.
Anne Boschini, Astri Muren and Mats Persson do the usual dictator games used to study generosity but with a few interesting twists. Instead of asking for demographic information at the start of the experiment, they ask about it after for some people. Or they do not mix genders in the experimental lab. The results are intriguing: women are only more generous when gender is asked before the experiment, or when the participants are of mixed gender. In fact, women are consistently generous, it is the men who change behavior. When they are reminded of their gender, or when women are present, they act tough, even though experiments are conducted anonymously. Pure machism.