People tell lies every day. They could be harmless, like saying you went out last Friday when you were actually watching Netflix on your couch. They could also be flagrant deceptions. The trick is ensuring you don't cross paths with the flagrant deceivers of the world--particularly in business situations where money or even your company's solvency may be on the line.

The situation where half-truths and lies by omission are even more common? The negotiation table, says Harvard professor Leslie K. John, writing in the July/August issue of the Harvard Business Review. While there is no fail-safe way of avoiding liars, here are John's seven strategies for detecting them. 

1.    Tell the truth.

John writes, "When someone shares sensitive information with us, our instinct is to match their transparency." That is not to say that you are going to start sharing your deepest darkest secrets just because a stranger vented to you in the subway. But humans are wired to at least want to share something when someone confides in them.

But how can this help you get a better deal? John notes two strategic advantages. First, it encourages intimacy. Research by two psychology professors found that strangers were more likely to become friends after partaking in mutual self-disclosure than by simply making small talk. And as John writes, "People lie less to those they know and trust than they do to strangers."

The second advantage is that if you encourage reciprocity by disclosing something first, your counterpart might feel compelled to follow your behavior. "At a minimum," John writes, "you are encouraging a conversation about interests, which is critical to creating mutually beneficial deals."

2.    Address their weaknesses.

Think back to how many times you have heard the same clichéd excuse "I didn't tell you because you didn't ask." Too many to count?

People often feel the need to withhold information, especially when such information might weaken their position in a business deal. Asking a straightforward question about a sensitive topic might improve your chances of getting a direct answer, or "the whole picture."

John cites a study by Schweitzer and Croson that found that 61 percent of negotiators "came clean when asked about information that weakened their bargaining power." The downside is that the same experiment showed that 39 percent of negotiators ultimately lied.

Still John contends it is more likely people will answer when questioned directly. She mentions a tip to increase your odds: make pessimistic statements. So if you want to know whether an investor will deliver on the promises he made you instead of asking "We are meeting with Whole Foods soon, right?" say "It's going to be difficult to meet with Whole Foods, isn't?"

John explains, "It seems to be easier for people to lie by affirming an untrue statement than by negating a true statement."

3.    Keep asking questions.

This is a strategy inspired by politicians, as they are experts in giving the "run-around" when asked a question. John notes "People are more impressed by eloquent sidestepping than by answers that are relevant but inarticulate."

A veteran negotiator might get around your questions by reciting a perfectly rehearsed and articulate spiel than giving you an actual answer. So in order to prevent this, you have to defend yourself against this dodging tactic. How? By becoming a human barricade and continue to ask your question until you've received a satisfying answer.

A tip from John, "Come to the table with a list of questions." That way you'll be sure to stay on point and not distracted by an expressive soliloquy.

4.    Don't be desperate.

Of course, every set of rules has its exceptions. In this case, John advises to restrain from making a lot of privacy and confidentiality assurances. She notes that might actually raise your negotiators' suspicions, "causing them to clam up and share less."

Unless you are asked directly, you do not need to proclaim safeguarding pledges. Instead focus on presenting your questions in a casual tone instead of a formal one. This way, John writes, "People are more likely to divulge sensitive information."

5.     Pause and listen.

This strategy encourages you to listen carefully to everything your counterpart says. John remarks, "People inadvertently leak information in all kinds of ways, including in their own questions."

So pay attention. You might learn a lot even from off-handed comments.

Imagine you learn your biggest competitor just had a round of businesses flown over to its headquarters and your most important supplier just happens to mention in passing he was in the exact same city at the same time. While it might not mean anything per se, that sure raises enough suspicion to do a little bit of digging.

6.     Offer options.

Another tactic you can use during a negotiation is a multiple-choice test. Offer two different options to carry out the deal--both equally acceptable to you--and ask your counterparts which they would prefer. This way as John observes, they are "leaking information about [their] priorities and giving you insight into [their] relative valuation of the issues up for negotiation."

Now you know what issues they might be willing to budge and which are essential to get the deal done.

7.     Have a contingency clause.

Another way to spot a liar is to request a contingency clause in your deal. John suggests attaching a financial consequence to the claims agreed on, but you can choose any kind of precaution (legal repercussions, for example.) The idea is that if the person you're negotiating with hesitates or "balks at agreeing to them" it raises a red flag and encourages you to investigate further.