How did your friend get you to babysit her kids for the weekend, or your sister talk you into hosting the next book club meeting? They probably asked when you were anxious about a work project or stressed about making an impending mortgage payment.
Stress, however, isn’t traditionally associated with altruism. When self-discipline wanes, such as when you are hurried, hungry or distracted, you are less likely to be helpful to strangers (if you’re late for an appointment, you’re probably not stopping to help the person who just dropped the contents of his briefcase). That makes intuitive sense: helping someone you are unlikely to ever see again when you feel least in control of your own life isn’t likely to be productive.
Yet such selfishness seems at odds with the need for cooperation in a social species that relies on support from others for survival. So researchers have suspected that this pattern may only hold true for strangers— and that stress and periods when you feel your life is out of your control might actually increase sacrifice toward loved ones since collaboration with those upon whom you regularly rely is essential for survival.