Reading people is central to my work — first as a CIA analyst, now as a CEO. And catching a liar is rarely as straightforward as we'd like to believe.
There's no physical response hardwired to deception. Some people are naturally nervous. Others carry such a strong sense of guilt that the mere suggestion they've done something wrong triggers suspicious behavior — even when they're completely innocent. This is exactly why polygraph tests are inadmissible in court. They measure physiological stress — heart rate, sweating, breathing — not deception itself. Anxiety and fear produce the same signals as lying, making false positives a serious problem.
So if lie detectors can't detect lies, and classic "tells" like fidgeting or avoiding eye contact don't reveal much either, how do you actually spot a liar?
Trust, but verify
This is a foundational motto at the CIA — and for good reason. Rather than relying on gut instinct in a single moment, build a complete picture by gathering information from multiple sources and monitoring behavior over time. Friends, colleagues, social media, past decisions — all of it contributes to a profile.
I apply this with every new client or partner I meet. I start with a baseline level of trust, then reassess at regular intervals. Trustworthiness isn't a snapshot. It's a pattern.
Pause and assess
Of course, we don't always have the luxury of time. Sometimes a judgment call has to be made in the moment. When that happens, run through these questions:
- What's the worst outcome if this person is lying — and is it a price I'm willing to pay?
- Does this person have an ulterior motive that benefits them at my expense?
- Are they a credible expert, or just projecting confidence?
- Can I independently verify or disprove what they're telling me?
- Are they manufacturing urgency?
That last one deserves special attention. Very little genuinely needs to be decided on the spot. If someone is pushing you toward a fast decision, ask yourself whose agenda that serves. Pressure is often a manipulation tactic, not a reflection of reality.
Start small
When you can't yet determine if someone is trustworthy, slow down. Rather than making a large bet on an untested person, get a sample size first.
Need a new supplier? Don't hand them a major contract on the strength of a promising pitch. Place a small order and see what actually happens. This isn't timidity — it's intelligence. We already do this in our personal lives without thinking about it. It's why we go on multiple dates before committing to a relationship. The same logic applies in business.
When in doubt, don't
If you've worked through all of the above and still can't get a clear read, the answer is simply: say no and move on. A strong default toward trust is healthy — but only when paired with honest analysis.
Ask questions. Evaluate the objective data. Build your picture over time. And above all, trust — but verify.