Does it pay to be kind to strangers? (bbc.com)

"That initial mistrust was a common theme for each of the following 13 days – in which she tried to offer strangers an umbrella on a rainy day, pay for someone’s parking ticket, and let fellow shoppers jump ahead of her in checkout queues. “Suspicion was the strongest reaction throughout,” she says. Each time, it was only when she offered a rational explanation – such as the fact she was waiting for someone at the checkout – that people would accept her offers. Looking back, Mann now explains it as “stranger danger”. “We’re brought up to expect strangers to put one over us,” she says."

However the deeper premise goes unexamined: all the correlative studies between gi ving and lon term happiness and health and not one discussion of whether healthier, happier people give more.