LOS ANGELES (MCT) — Feeling generous? Think it over a little and then see how you feel.

While humankind has often judged itself as greedy and self-interested, a growing body of evidence suggests that people’s default mode is to be giving and cooperative — particularly in times of stress. In fact, some behavioral scientists argue that ancient humans would never have survived their harsh environment and proliferated so successfully had they lacked the urge to help others.