Lost letter experiment suggests wealthy London neighborhoods are 'more altruisitic' echoes that sentiment. The experiment dropped addressed envelopes on the sidewalks of 20 London neighborhoods and recorded whether someone took the trouble to drop them into a mailbox. The results are dramatic - 87 percent of the letters were posted in the wealthier neighborhoods compared to 37 percent in poorer neighborhoods. The experimenters carefully made the letters gender and race neutral, and they placed the postage stamp on them. The finder had only to deposit the letter in a nearby mailbox.
Altruism is important to society, because at the individual level, we must construct defenses if there is the likelihood of selfishness or attack. If we live in a culture with high level of altruism, then the energy or cost of establishing defenses can be used for positive or more productive uses.
I am concerned that if we see further deterioration of the middle class in western nations, a direct impact will be the productivity of the cultures. There are multiple factors in this phenomena, but it is obvious that we all benefit when we can trust others.