SOCIAL scientists believe that the empathetic, nurturing behaviors of sisters rub off on their brothers. For example, studies led by the psychologist Alice Eagly at Northwestern University demonstrate  that women tend to do more giving and helping in close relationships than men. It might also be that boys feel the impulse — by nature and nurture — to protect their sisters. Indeed, Professor Eagly finds that men are significantly more likely to help women than to help men.

By ADAM GRANT Published: July 20, 2013

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