Excerpt from Blink by Malcolm Gladwell, plus links to reviews, author biography & more

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.'"

This is the full text of Chapter 1 of Blink (pages 18-47). Copyright © 2005 by Malcolm Gladwell. All rights reserved. No part of this book maybe reproduced without written permission from the publisher, Little, Brown & Co.