REASON 06 OF 10

One kind act becomes three.

Generosity spreads from person to person, up to three people away.

What the researchers did

James Fowler and Nicholas Christakis studied groups of strangers who played a series of cooperation games. In each round, players could give money to a shared pot that benefited the group, and every round they were mixed with new people they would never meet again, so nobody could repay a favour directly.

What they found

When one person gave, the people in their group gave more in later rounds, to different people, who in turn gave more themselves. Generosity travelled up to three steps away from where it started, and each act of giving was roughly tripled over the course of the games. The researchers note that selfishness spreads in the same way.

What it means on G-Day

A thank-you reaches further than the person in front of you. The rider you thank may be a little kinder to the next customer, who may be kinder to someone else. Ten thank-yous can start many more, which is exactly the chain we hope to set off on 10 October.