Marriage as a Repeated Game

One of the major results of non-cooperative game theory is that if two people have to play the same game over and over forever (till death do us part), then it is perfectly rational for the player to cooperate. Consider the classic Prisoner’s dilemma game. If both players cooperate, they each get $100. If one defects and the other cooperates, the defector gets an extra $30 but the other guy loses $60. If they both defect, they each get $70. The following list shows the possible outcomes:

1. (c,c): ($100,$100)


2. (d,c): ($130, $40)


3. (c,d): ( $40,$130)


4. (d,d): ( $70, $70)

Clearly, playing “defect” is not nice.

What if one of the players plays “defect”? The other player needs to punish him by playing “defect” until the first player cooperates. But, in the real world, what if it isn’t entirely clear who was the first player to play “defect”? Then cooperation may never happen again, and that’s really a pity.

Marriage can be like this. In the beginning, the husband and the wife cooperate naturally. But then, once in a while, one or the other does something selfish. Maybe it is minor, like leaving socks on the floor or forgetting to make the bed. At first the spouse might be forgiving, but then over time the instinct to “punish” the spouse becomes overwhelming. The aggrieved spouse might yell, or might give the dreaded “silent treatment”.

My wife views this blog as a sort of “defection”. It only benefits me, (she never reads it), and it represents time that could have been spent doing things that my whole family could enjoy instead of just me. Now, my wife does not mean that I must do everything for the good of the entire family, but in the margin, an extra hour of blogging is an hour lost to family activities: gardening, home improvement, family fun.

My wife read my emails. She cannot understand why so many of my readers who write emails are from India. She especially disliked this one email, “Who’s this Swati? Why is she flirting with you!” “Oh, Swati is a girl?” I asked innocently.

The bottom line: either I find a really good reason for my wife to like my blog or I will have to drastically reduce my blogging. Maybe I can work out some kind of deal with her: I do X, Y, and Z and she’s let me spend 10 hours a week blogging. Or maybe I can figure out some plausible way that one could get rich blogging, (seriously, someone will figure it out).

In any case, I don’t dare let her think that I am playing “defect” in the hopes that she will give up and let me do as I please. Some couples start the “defect, defect” option and never stop. It happens all the time. I must cooperate.

I know someone who started playing the “defect, defect” option with her sister. She tells me, “I miss her, but I cannot ignore what she said to me.” Apparently her sister feels the same way. Apparently, they will play the “defect, defect” forever. It seems a great pity; they were so close. But at least I can learn from that example.

Update: The always excellent Acorn, by Nitin Pai, links to this piece.