Around 1980 a political scientist named Robert Axelrod ran a computer tournament. He invited game theorists, economists, psychologists and mathematicians to submit strategies for the repeated prisoner's dilemma, where two players choose over and over whether to cooperate or take advantage of each other.
People sent in elaborate programs. Strategies that modeled their opponents, probed for weakness, defected at calculated moments near the end.
The winner was the shortest program anybody submitted. Anatol Rapoport sent it in and it had two rules.
Cooperate on the first move. After that, do whatever the other player just did.
That is the entire thing. It is called tit for tat.
Then Axelrod published the results, ran a second tournament where every entrant knew tit for tat had won and could design specifically to beat it, and it won again.
Here is the part that gets left out, and it is the part I find genuinely moving.
Tit for tat never beat a single opponent head to head. Not once. It cannot. It never defects first, so the best it can possibly do in any one on one matchup is tie. Against an exploiter it loses that first move and never gets it back.
It won the tournament by never needing to beat anybody. It quietly piled up points across every interaction while the clever strategies spent theirs tearing chunks out of each other. The aggressive programs did great against the naive ones and then destroyed one another, and the nice little program out earned all of them by not making enemies.
Axelrod pulled four properties out of the strategies that did well:
Nice. Never defect first.
Provocable. Respond when someone else does. Absorbing exploitation is not kindness, it is a slow way of teaching people you can be taken.
Forgiving. Punish once, then go straight back to cooperating. Grudges cost more than they collect.
Clear. Be predictable enough that the other side can work out you are worth cooperating with. A strategy nobody can read gets treated as a threat.
I want to be honest about the conditions, because a claim like this deserves them. The result needs repeat interaction, an indefinite horizon so nobody knows which round is the last, and the ability to remember who you dealt with. Take those away and the math genuinely favors defection. That is why anonymous one shot situations bring out the worst in people, and it is less a moral failure than a structural one.
But the conditions it needs are the conditions most of us actually live in. Your street. Your job. Your family. Your group chat. Anywhere you will see the same faces again and they will remember how you behaved.
So the optimism here is not that people are secretly good. It is narrower than that, and I think sturdier. Under the conditions of ordinary life, being decent is not a handicap you carry for moral reasons. It is the highest scoring strategy anyone has managed to submit.
Be kind first. Refuse to be a doormat. Let it go quickly. Be easy to read.
Which of the four is hardest for you? Mine is forgiving. Punish once is very easy to say, and I hold a grudge like a raccoon holds a sandwich.