The Secrets in Your Stuff Psychologist says he can predict personality by snooping in a home or office.

July 1, 2008 -- Sam Gosling is a distinguished psychologist who employs an unusual technique to probe personalities. He likes to snoop, and not just in your medicine cabinet. Gosling wants to go through all your stuff -- even sit in your bathtub -- to find out what's going on in your head.

His new book, "Snoop," is based on the theory that sometimes going through a person's belongings can provide insight into personality.

"A snooper does what we all do in looking around people's places," Gosling said. "I think we all do it. It's a very natural thing to do, but really as a snooper you are trying to bring an understanding of the psychology behind it, what drives the placement of objects."

The first thing Gosling does is sit down in a space and look around, "giving the salient items time to fade away a bit, and the broader themes to come out."

"Nightline" decided to test Gosling at the office of his friend and colleague, John Jost, at New York University. The fellow psychologist didn't mind Gosling's snooping and said that while he tidied up his office beforehand, he didn't do any major organizing.

Gosling went through drawers, examined pictures, checked the status of office supplies and analyzed the position of Jost's desk -- all providing clues to Jost's personality.

The goal, Gosling said, is to "look at the big picture. And look for themes. Because any single item could be misleading. There could be something here that really doesn't reflect what the occupant is like. It's just there because it's for a teaching demonstration, or a gift for somebody else, or things that aren't really important, or somebody else left it there."

He won't make a judgment about Jost solely based on the fact that he has a book in his office called "Why Men Rebel."

"It should be one piece of the puzzle," he said. "It could reflect many different things, you know? There are many different reasons you might have that. So we have to try to narrow down the likely reasons you have that."

Gosling noted that Jost's office is "pretty organized," and said that he can tell a lot from someone's music collection. Jost has a lot of classic rock.

"So people who like rock, they tend to be higher on openness," Gosling said. "And also people who like classical ... and jazz, actually."

On the other hand, he also said that "people who like rock tend to be lower on conscientiousness, so looking at this, I'd have to combine that with my other rating saying that he was higher on conscientiousness. So it's all a puzzle, you're always combining bits of information here."

The contents of someone's office can even indicate how he might vote, according to Gosling, who said that Jost's openness trait would align him with "people who vote for liberal candidates."

And indeed, Jost said he is a liberal and is planning to vote for Barack Obama.

"I think Sam is an excellent personality psychologist and a very perceptive person," Jost said. "And I think he would get at least an A-, maybe an A."

Gosling also visited Jamie Napier, a graduate student at NYU. He described the office she shares with two colleagues as having a "sort of strong, post-feminist kind of strong and sexy look. ... Competent, but not at the expense of being, you know, glamorous and feminine."

An empty wine bottle, some hair glitter, mail from 2006, a few razors in a drawer -- all became part of Gosling's evaluation.

"She's sort of disorganized in many ways. She has broad interests. I would say that she is OK with some level of glamour going on here," he said. "And I think that social relationships are important to her. She's not a loner."

The office was decorated with Christmas tree lights, which Gosling said could be an attempt to brighten up a constrained space with no windows.

"People who decorate places and people who try to create a stimulating place tend to be more extroverted," he said.

Pictures of Napier's dogs indicate that "she's not completely cutting off her personal life from her workplace. Some people don't have any evidence of [their personal life], they really keep those things very strict, so she more integrates her work and her home self."

Gosling evaluated Napier as "someone who's sort of careless, like scatterbrained."

Napier agrees that she's disorganized.

"Yes, I am, I know I am," she said. "I tend not to throw things away much."

And she agreed that she cares about her social relationships, hence the empty wine bottle.

"I have two other officemates, and we'll have a glass of wine before we go out, or something like that," she said.

And as for Napier's political leanings, Gosling said that people who are "broadminded and messy" are usually liberal voters, and he's right when it comes to Napier.

Snooping can be useful in the office, Gosling said.

"If I really wanted to know who I should promote or who I shouldn't promote, or who would be best suited for a certain job, I should be making that decision on the basis of what people are really like, not how they appear or how they say they are," he said. "And to the extent that the snooping helps me get a more accurate impression, it's justified."

So should bosses be walking around looking at their employees' work spaces?

"I think if they want to know both what people are like, but also how people want to be seen," he said. "Even if people want to be seen how they actually aren't, it's still useful to know that that's what they want."

We thought Gosling might be a little too at home at the psychology office at NYU, so we decided to test his snooping skills at the home of ABC News correspondent Sharyn Alfonsi.

It wasn't hard for him to discover that she is very organized.

"This is great. Unbelievable," he said. "Glasses all lined up. Amazing. Tape measures right next to each other in the tape measure spot. Office supplies labeled."

"This is almost an open-and-shut case, I mean, you don't really need to look for more stuff. Everything is in its place, it's just marvelous," he said. "Things are not left to chance here. This couldn't be further from Jamie's response.

"You are clearly a very effective person, you get things done, things are put away," he said.

Gosling said snooping can be more accurate than talking to someone, in many cases. The strongest cues come when a space is distinctive, and Gosling said the same rules apply to work spaces and living spaces.

"If you can think of objects, regardless of where they are, be it offices, bedrooms, refrigerators, medicine cabinet, you can apply those principles regardless of where you go," he said. "Of course the specific objects vary across these domains, but you can think about these in the same system."

If he had only15 minutes to snoop in a home, Gosling would start in the living room (the public space) and then move to the private spaces, like a bedroom or office.

"What I really like to do is look at the books that are out for people to see -- 'Look at my highbrow interesting things' -- and compare them to ones in the private places," he said.

"I'm quite conscious about thinking when am I in the place that is for others to see, when am I in the private space ... and that can even be within a room," he said. "So when I go to an office, for example, I look at the things that are facing you as a visitor and then crawl underneath the desk, behind and see if that's where the stuff is being hidden."

And if you've been snooping in your neighbor's medicine cabinet, you might be surprised to learn that isn't the best place to start.

"Medicine cabinets are surprisingly uninformative because there's such a standard vocabulary of items within that," he said. "Same thing goes for the refrigerator. That's often thought to be very revealing, but they don't vary that much."

And you shouldn't feel guilty about snooping, because you're not the only one.

"I think nearly everybody snoops to some extent," he said.