One mystery of human behavior is why we (sometimes) behave altruisticly. One explanation is found in “costly signaling theory.”
A great example of costly signaling is found in male peacocks with their large, beautiful tails. The tails of male peacocks waste energy, reduce their mobility and draw predators. One would think that evolutionary theory would suggest that male peacocks would evolve to have smaller, less colorful tails. The bigger and more impractical tail paradoxically suggests great strength and fitness. A lesser peacock wouldn’t have survived with a large colorful plume. This is attractive to female peacocks who recognize the strength signaled by the costly tail. Another example is that of bucks with large antlers.
The costly signaling theory may also explain human altruism towards strangers. Acting altruisticly to those in your group or tribe arguably directly helps your survival, but altruism directed towards total strangers and people in foreign countries is harder to explain. The costly signaling theory offers an explanation by suggesting that acting altruisticly, especially to strangers, demonstrates status and financial fitness. Altruism within your group or community likewise increases status and signals financial fitness. Those signals of status and fitness help attract mates and improve position in social groups which bring a number of benefits
Of course there are additional reasons we behave altruisticly in addition to costly signaling.
Have a great weekend.