“You would think that criticism would be the worst,” Gottman says, “because criticism is a global condemnation of a person’s character. Yet contempt is qualitatively different from criticism. With criticism I might say to my wife, ‘You never listen, you are really selfish and insensitive.’ Well, she’s going to respond defensively to that. That’s not very good for our problem solving and interaction. But if I speak from a superior plane, that’s far more damaging, and contempt is any statement made from a higher level. A lot of the time it’s an insult: ‘You are a bitch. You’re scum.’ It’s trying to put that person on a lower plane than you. It’s hierarchical.”

Gottman has found, in fact, that the presence of contempt in a marriage can even predict such things as how many colds a husband or a wife gets; in other words, having someone you love express contempt toward you is so stressful that it begins to affect the functioning of your immune system. “Contempt is closely related to disgust, and what disgust and contempt are about is completely rejecting and excluding someone from the community. The big gender difference with negative emotions is that women are more critical, and men are more likely to stonewall. We find that women start talking about a problem, the men get irritated and turn away, and the women get more critical, and it becomes a circle. But there isn’t any gender difference when it comes to contempt. Not at all.” Contempt is special. If you can measure contempt, then all of a sudden you don’t need to know every detail of the couple’s relationship.

I think that this is the way that our unconscious works. When we leap to a decision or have a hunch, our unconscious is doing what John Gottman does. It’s sifting through the situation in front of us, throwing out all that is irrelevant while we zero in on what really matters. And the truth is that our unconscious is really good at this, to the point where thin-slicing often delivers a better answer than more deliberate and exhaustive ways of thinking.

Imagine that you are considering me for a job. You’ve seen my résumé and think I have the necessary credentials. But you want to know whether I am the right fit for your organization. Am I a hard worker? Am I honest? Am I open to new ideas? In order to answer those questions about my personality, your boss gives you two options. The first is to meet with me twice a week for a year—to have lunch or dinner or go to a movie with me—to the point where you become one of my closest friends. (Your boss is quite demanding.) The second option is to drop by my house when I’m not there and spend half an hour or so looking around. Which would you choose?

The seemingly obvious answer is that you should take the first option: the thick slice. The more time you spend with me and the more information you gather, the better off you are. Right? I hope by now that you are at least a little bit skeptical of that approach. Sure enough, as the psychologist Samuel Gosling has shown, judging people’s personalities is a really good example of how surprisingly effective thin-slicing can be.

Gosling began his experiment by doing a personality workup on eighty college students. For this, he used what is called the Big Five Inventory, a highly respected, multi-item questionnaire that measures people across five dimensions:

1. Extraversion. Are you sociable or retiring? Fun-loving or reserved?

2. Agreeableness. Are you trusting or suspicious? Helpful or uncooperative?

3. Conscientiousness. Are you organized or disorganized? Self-disciplined or weak willed?

4. Emotional stability. Are you worried or calm? Insecure or secure?

5. Openness to new experiences. Are you imaginative or down-to-earth? Independent or conforming?

Then Gosling had close friends of those eighty students fill out the same questionnaire.

When our friends rank us on the Big Five, Gosling wanted to know, how closely do they come to the truth? The answer is, not surprisingly, that our friends can describe us fairly accurately. They have a thick slice of experience with us, and that translates to a real sense of who we are. Then Gosling repeated the process, but this time he didn’t call on close friends. He used total strangers who had never even met the students they were judging. All they saw were their dorm rooms. He gave his raters clipboards and told them they had fifteen minutes to look around and answer a series of very basic questions about the occupant of the room: On a scale of 1 to 5, does the inhabitant of this room seem to be the kind of person who is talkative? Tends to find fault with others? Does a thorough job? Is original? Is reserved? Is helpful and unselfish with others? And so on. “I was trying to study everyday impressions,” Gosling says. “So I was quite careful not to tell my subjects what to do. I just said, ‘Here is your questionnaire. Go into the room and drink it in.’ I was just trying to look at intuitive judgment processes.”

How did they do? The dorm room observers weren’t nearly as good as friends in measuring extraversion. If you want to know how animated and talkative and outgoing someone is, clearly, you have to meet him or her in person. The friends also did slightly better than the dorm room visitors at accurately estimating agreeableness—how helpful and trusting someone is. I think that also makes sense. But on the remaining three traits of the Big Five, the strangers with the clipboards came out on top. They were more accurate at measuring conscientiousness, and they were much more accurate at predicting both the students’ emotional stability and their openness to new experiences. On balance, then, the strangers ended up doing a much better job. What this suggests is that it is quite possible for people who have never met us and who have spent only twenty minutes thinking about us to come to a better understanding of who we are than people who have known us for years. Forget the endless “getting to know” meetings and lunches, then. If you want to get a good idea of whether I’d make a good employee, drop by my house one day and take a look around.

If you are like most people, I imagine that you find Gosling’s conclusions quite incredible. But the truth is that they shouldn’t be, not after the lessons of John Gottman. This is just another example of thin-slicing. The observers were looking at the students’ most personal belongings, and our personal belongings contain a wealth of very telling information. Gosling says, for example, that a person’s bedroom gives three kinds of clues to his or her personality. There are, first of all, identity claims, which are deliberate expressions about how we would like to be seen by the world: a framed copy of a magna cum laude degree from Harvard, for example. Then there is behavioral residue, which is defined as the inadvertent clues we leave behind: dirty laundry on the floor, for instance, or an alphabetized CD collection. Finally, there are thoughts and feelings regulators, which are changes we make to our most personal spaces to affect the way we feel when we inhabit them: a scented candle in the corner, for example, or a pile of artfully placed decorative pillows on the bed. If you see alphabetized CDs, a Harvard diploma on the wall, incense on a side table, and laundry neatly stacked in a hamper, you know certain aspects about that individual’s personality instantly, in a way that you may not be able to grasp if all you ever do is spend time with him or her directly. Anyone who has ever scanned the bookshelves of a new girlfriend or boyfriend—or peeked inside his or her medicine cabinet—understands this implicitly: you can learn as much—or more—from one glance at a private space as you can from hours of exposure to a public face.

Just as important, though, is the information you don’t have when you look through someone’s belongings. What you avoid when you don’t meet someone face-to-face are all the confusing and complicated and ultimately irrelevant pieces of information that can serve to screw up your judgment. Most of us have difficulty believing that a 275-pound football lineman could have a lively and discerning intellect. We just can’t get past the stereotype of the dumb jock. But if all we saw of that person was his bookshelf or the art on his walls, we wouldn’t have that same problem.