Want to tell if someone is lying to you? A body language expert shares the biggest signs to look for

Want to be a pro at spotting liars? Pay close attention to their body language.

Whether in your personal or professional life, your success depends>Step 1: Determine their baseline

A person's baseline is how they act when they are under normal, non-threatening conditions.

You can establish baselines by sitting down with the person you want to read better — your child, spouse, friend, co-worker, boss — and talking casually to them about neutral topics that they would have no reason to lie about, such as the weather or what they want to have for dinner.

Take note of how they act, hold their body, sound and their facial movements.>Step 2: Look for red flags

There is no universal cue that is a guaranteed indicator of lying, and any major shift from a person's baseline may indicate they are being dishonest.

However, there are special cues that liars often use. The most common>Zoom In IconArrows pointing outwardsFacial "fear microexpressions" that liars often useCredit: The Science of People | CNBC Make It

Remember, these signs are>Step 3: Find a cluster of three

It's important to never take a single red flag as a sure sign of lying. Most liars leak more than one lying cue in a matter of minutes or even seconds. This is called a cluster.

To more accurately decipher if someone is lying, look for a cluster of three red flags.

For example, a colleague is asked about the status of the new client. She responds by flashing a fear microexpression and saying, "I did go to the bar?" — with a question inflection.

Or a manager asks an employee about this month's quota. The employee purses his lips, takes a step back and gives a reply with no personal pronouns: "Doing good! On track to meet it this month."

I believe it's better to always assume truth from people. A way to protect yourself against liars is to merely take note of the baselines of the most important people you engage with: How do they act, sound and behave when telling the truth?

Any red flags or deviations from this behavior can be an early sign that a topic needs further investigation.