The interceptors came up with descriptions of the fists and styles of the operators they were following. They assigned them names and assembled elaborate profiles of their personalities. After they identified the person who was sending the message, the interceptors would then locate their signal. So now they knew something more. They knew who was where. West goes on: “The interceptors had such a good handle on the transmitting characteristics of the German radio operators that they could literally follow them around Europe—wherever they were. That was extraordinarily valuable in constructing an order of battle, which is a diagram of what the individual military units in the field are doing and what their location is. If a particular radio operator was with a particular unit and transmitting from Florence, and then three weeks later you recognized that same operator, only this time he was in Linz, then you could assume that that particular unit had moved from northern Italy to the eastern front. Or you would know that a particular operator was with a tank repair unit and he always came up on the air every day at twelve o’clock. But now, after a big battle, he’s coming up at twelve, four in the afternoon, and seven in the evening, so you can assume that unit has a lot of work going on. And in a moment of crisis, when someone very high up asks, ‘Can you really be absolutely certain that this particular Luftwaffe Fliegerkorps [German air force squadron] is outside of Tobruk and not in Italy?’ you can answer, ‘Yes, that was Oscar, we are absolutely sure.’”

The key thing about fists is that they emerge naturally. Radio operators don’t deliberately try to sound distinctive. They simply end up sounding distinctive, because some part of their personality appears to express itself automatically and unconsciously in the way they work the Morse code keys. The other thing about a fist is that it reveals itself in even the smallest sample of Morse code. We have to listen to only a few characters to pick out an individual’s pattern. It doesn’t change or disappear for stretches or show up only in certain words or phrases. That’s why the British interceptors could listen to just a few bursts and say, with absolute certainty,

“It’s Oscar, which means that yes, his unit is now definitely outside of Tobruk.” An operator’s fist is stable.

What Gottman is saying is that a relationship between two people has a fist as well: a distinctive signature that arises naturally and automatically. That is why a marriage can be read and decoded so easily, because some key part of human activity—whether it is something as simple as pounding out a Morse code message or as complex as being married to someone—has an identifiable and stable pattern. Predicting divorce, like tracking Morse Code operators, is pattern recognition.

“People are in one of two states in a relationship,” Gottman went on. “The first is what I call positive sentiment override, where positive emotion overrides irritability. It’s like a buffer. Their spouse will do something bad, and they’ll say, ‘Oh, he’s just in a crummy mood.’ Or they can be in negative sentiment override, so that even a relatively neutral thing that a partner says gets perceived as negative. In the negative sentiment override state, people draw lasting conclusions about each other. If their spouse does something positive, it’s a selfish person doing a positive thing. It’s really hard to change those states, and those states determine whether when one party tries to repair things, the other party sees that as repair or hostile manipulation. For example, I’m talking with my wife, and she says, ‘Will you shut up and let me finish?’ In positive sentiment override, I say, ‘Sorry, go ahead.’ I’m not very happy, but I recognize the repair. In negative sentiment override, I say, ‘To hell with you, I’m not getting a chance to finish either. You’re such a bitch, you remind me of your mother.’”

As he was talking, Gottman drew a graph on a piece of paper that looked a lot like a chart of the ups and downs of the stock market over the course of a typical day. What he does, he explains, is track the ups and downs of a couple’s level of positive and negative emotion, and he’s found that it doesn’t take very long to figure out which way the line on the graph is going. “Some go up, some go down,” he says. “But once they start going down, toward negative emotion, ninety-four percent will continue going down. They start on a bad course and they can’t correct it. I don’t think of this as just a slice in time. It’s an indication of how they view their whole relationship.”

Let’s dig a little deeper into the secret of Gottman’s success rate. Gottman has discovered that marriages have distinctive signatures, and we can find that signature by collecting very detailed emotional information from the interaction of a couple. But there’s something else that is very interesting about Gottman’s system, and that is the way in which he manages to simplify the task of prediction. I hadn’t realized how much of an issue this was until I tried thin-slicing couples myself. I got one of Gottman’s tapes, which had on it ten three-minute clips of different couples talking. Half the couples, I was told, split up at some point in the fifteen years after their discussion was filmed. Half were still together. Could I guess which was which? I was pretty confident I could. But I was wrong. I was terrible at it. I answered five correctly, which is to say that I would have done just as well by flipping a coin.

My difficulty arose from the fact that the clips were utterly overwhelming. The husband would say something guarded. The wife would respond quietly. Some fleeting emotion would flash across her face. He would start to say something and then stop. She would scowl. He would laugh. Someone would mutter something. Someone would frown. I would rewind the tape and look at it again, and I would get still more information. I’d see a little trace of a smile, or I’d pick up on a slight change in tone. It was all too much. In my head, I was frantically trying to determine the ratios of positive emotion to negative emotion. But what counted as positive, and what counted as negative? I knew from Susan and Bill that a lot of what looked positive was actually negative. And I also knew that there were no fewer than twenty separate emotional states on the SPAFF chart. Have you ever tried to keep track of twenty different emotions simultaneously? Now, granted, I’m not a marriage counselor. But that same tape has been given to almost two hundred marital therapists, marital researchers, pastoral counselors, and graduate students in clinical psychology, as well as newlyweds, people who were recently divorced, and people who have been happily married for a long time—in other words, almost two hundred people who know a good deal more about marriage than I do—and none of them was any better than I was. The group as a whole guessed right 53.8 percent of the time, which is just above chance. The fact that there was a pattern didn’t much matter. There were so many other things going on so quickly in those three minutes that we couldn’t find the pattern.

Gottman, however, doesn’t have this problem. He’s gotten so good at thin-slicing marriages that he says he can be in a restaurant and eavesdrop on the couple one table over and get a pretty good sense of whether they need to start thinking about hiring lawyers and dividing up custody of the children. How does he do it? He has figured out that he doesn’t need to pay attention to everything that happens. I was overwhelmed by the task of counting negativity, because everywhere I looked, I saw negative emotions. Gottman is far more selective. He has found that he can find out much of what he needs to know just by focusing on what he calls the Four Horsemen: defensiveness, stonewalling, criticism, and contempt. Even within the Four Horsemen, in fact, there is one emotion that he considers the most important of all: contempt. If Gottman observes one or both partners in a marriage showing contempt toward the other, he considers it the single most important sign that the marriage is in trouble.