Wouldn't it be great to be able to just look at someone and tell what they're really like?

Sherlock Holmes does this all the time and it's incredibly cool. Check out this clip from the BBC show Sherlock.

Of course, Sherlock Holmes is a fictional character, and nobody can read people quite that well. We can all get better at it, though.

But where do you learn a skill like that? And I mean for real — methods backed by science.

So I called a guy who has the answers: Sam Gosling.

Sam is a personality psychologist at the University of Texas at Austin and author of the book Snoop: What Your Stuff Says About You. Here's what you'll learn from Sam in the post below:

What really works (and doesn't) when reading people.

How to get more accurate first impressions.

What someone's home or office can tell you about them.

What someone's Facebook profile really says about their personality.

How to tell when someone is faking and putting up a false front.

Okay, put on your deerstalker cap and let's get to work.

What Sherlock Gets Wrong — And How You Can Get It Right

So what does Sam say is implausible about Sherlock Holmes?

You just can't tell that much about someone from one little thing. Here's Sam:

Sherlock Holmes will notice a shoe scuff mark on the side of the wall and from that he is able to completely realize this person must have fallen a certain way and done this and that and so on. But in reality there's 20 different ways you could have had that scuff mark. That's why we have to look for trends in behavioral residue.

It's really about detecting patterns. Themes. Trends. Here's Sam:

I look at the photos people have of themselves. Those can often be very diagnostic about people's identity. I always ask myself: "Of the 10,000 photos you could've put up, why did you put up these three?" Do the photos consistently show a theme of the person as the scientist, or as the hero, or as the family person? Those tend to be very helpful.

Sam uses three categories for things that tell you about someone's personality:

Identity Claims Feeling Regulators Behavioral Residue

Let's break them down.

1. Identity Claims

People want to be understood. These are the things that say something about who the person is or how they want to be perceived.

A class ring. T-shirts with slogans. Music. Tattoos. Pay attention to them because they're usually accurate signs. Here's Sam:

Identity claims are deliberate statements we make about our attitudes, goals, values, etc… One of the things that's really important to keep in mind about identity statements is because these are deliberate, many people assume we are being manipulative with them and we're being disingenuous, but I think there's little evidence to suggest that that goes on. I think generally people really do want to be known. They'll even do that at the expense of looking good. They'd rather be seen authentically then positively if it came down to that choice.

2. Feeling Regulators

That photo of their daughter that's facing their chair? That's not for you. That's for them. It makes them feel good.

3. Behavioral Residue

This is what Sherlock Holmes is usually looking for. The stuff we leave around that shows what we've been up to lately. What's the best source of behavioral residue?

Look in someone's trash can. Seriously. It's very, very telling.

Why? Because it's not sculpted in any way. It accurately provides clues to what we've been doing.

Ask yourself right now: how often do you monitor your trash can for what others might think of you? You don't.

As Sam says in his book, Snoop: "Garbage is the window to the soul."

(To learn how to read body language like a pro, click here.)

Okay, so we have the basics. How can you best put these ideas to use when you meet someone new?

Trust First Impressions — But Be Ready To Revise

Good News: your first impressions are usually pretty accurate. Bad News: whether they are wrong or right, first impressions affect us in a big way and we are slow to change them.

Here's Sam:

First impressions are often quite helpful but you have to be willing to update them quite rapidly. That's what's very hard to do.

What should we definitely trust in first impressions? If someone seems extroverted or confident, they probably are.

What can clothing tell you?

Are the clothes expensive? Is a woman showing cleavage? Does it show off a guy's muscles? Hello, narcissism. Here's Sam:

Narcissists tend to put much more care into their appearance. The women tend to show more cleavage. The guys tend to show more muscles.

These days we often meet people first via email. Want a clue as to someone's personality? Look at their sig. Here's Sam:

I do think that the signature files at the bottom are a good indicator to somebody's identity. You can get quite a high fidelity signal about someone's values if they have a quote at the end of their emails.

(To learn more about what the music you love says about you, click here.)

Not everybody has a quote at the bottom of their emails — but they probably have a Facebook account. Can we trust how they're presenting themselves?

Facebook Profiles Are Actually Very Accurate

Research shows they're a rich source of information about someone's personality.

University of Texas psychology professor Sam Gosling. University of Texas

I know, I know: some of you are thinking about that friend who is always making themselves look good.

Don't sweat that too much. Sam says it doesn't matter. You're still going to get a pretty accurate idea of who they are.

Why? For one, someone who wants to seem cultured is really not going to go to the trouble of attending the opera every week and posting photos. It's too much trouble.

And Facebook has a level of accountability. If you posted lots of stuff that isn't like you at all, friends could call you out on it — and people know that. Here's Sam:

It overwhelmingly gives a more accurate impression rather then an inflated impression. Let's say I wanted to give the impression that I was very highbrow. What would I actually have to do in order to give that impression? I don't really know much about obscure classical music. It would be very hard for me to talk in a compelling way about it. Am I going to actually go to some kind of shows and have pictures of me in those places? It requires quite a lot of effort. One of the reasons why Facebook is quite helpful is because it really does reflect what people are doing. Another reason is because of the high accountability there. If I posted photos of me parachuting, swimming with sharks, etc. all of my friends would immediately call it out as a fake, because they would know that's not what I do.

What's the single best personality predictor Sam has ever found? Personal websites.(Yes, I'm cringing right now.)

How about online dating profiles? Sam hasn't done much research here but he guesses they're less telling than Facebook profiles but still pretty indicative.

People don't want to be an utter disappointment when they meet a date in person but there's not the level of accountability that Facebook has. Here's Sam:

Websites and Facebook profiles provide quite an accurate impression, whereas with the dating websites, you want to put your good side forward. It shouldn't be such a good side that you create disappointment, so it's obviously quite a balance to predict. I'd expect you'd have reasonable levels of accuracy, but not as high as these other domains where there's more accountability.

(To learn more about what the words you use say about you, click here.)

So that's online but what about in the real world? When you look at someone's home or office what can you really learn about them?

What would Sherlock do? BBC One/Sherlock

What Someone's Home And Office Tells You About Who They Are

Merely looking at the outside of someone's house (Seems inviting? Christmas decorations up?) can accurately tell you how sociable they are. Bedrooms can clue you in to how they vote.

Have they got a variety of cool objects? Those people are open to new experiences.

Are those things presented in a neat and tidy way? That signals conscientiousness and reliability.

Is the place comfortable? Inviting? You've got yourself an extrovert.

Here's Sam:

What we found in both homes and offices is that clues to conscientiousness and openness are pretty strong. People who are higher on extroversion, they tend to have inviting spaces. They'll have the door open and a more comfortable space. They essentially want people to come in there and linger. Maybe they have candy on the desk, that sort of thing.

Another great clue is to look at which direction things are facing.

Are those family photos facing where the guests sit or where the owner sits? How about those framed diplomas?

That tells you who those items are designed to influence: you or them. Here's Sam:

The location of things or which way they're facing can really tell you the psychological function that item is serving. Maybe it's very close to where a person works or sits a lot, or something is deliberately placed right in the middle of the room. Those tend to be significant things.

Similarly, you can get clues to fakery and phoniness by looking at how the items in various rooms differ. Generally, the more private the room, the more accurate the signal you'll get.

Those untouched highbrow books on the shelf in the living room collecting dust? Yeah, someone's trying to look smart.

But what about that well-thumbed romance novel or self-help book lying next to the bed? That's who they really are.

(For more on how to accurately detect lies, click here.)

Okay, Sherlock-in-training, we have a lot of new tools. Let's round everything up and learn the best way to put them to use.

Sum Up

Here are some of Sam's tools for reading people:

Don't make assumptions based on a single item. Look for trends and themes. (And definitely eye the trash can.) First impressions are often accurate but be ready to update them quickly. Extroversion and self-esteem are easy to spot. Clothing can clue you in to narcissism. Personal websites, Facebook profiles and email sigs can generally be trusted. Homes and offices can tell you who is extroverted, conscientious and open to new experiences. Look at which direction things are facing. The more private a room, generally the more accurate it is.

Hopefully these can help you learn more about new friends or old friends and forge a closer bond.

But you might want to keep quiet about some of your insights. I asked Sam how people react to his being an expert in this field. He replied:

I've had lots of invitations not to visit people's houses.

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