How to Tell If Someone Is Lying

By
Mia Belle Frothingham
|
Updated on
Reviewed by
Saul McLeod, PhD
&
Olivia Guy-Evans, MSc

Spotting a lie means watching for a shift away from how someone normally acts, not for any single “tell.” No cue proves dishonesty on its own. The same logic applies whether you suspect a lie at work, in a relationship, or in an interview.

a woman holding a finger up to her lips
Look for inconsistencies in their story, exaggerated details, and avoiding eye contact. Liars tend to touch or cover their mouth more and shift in their seats. They may speak in a higher pitch or clearing their throat often. Pay attention if they repeat your questions before answering and provide extra unsolicited information. These signals suggest dishonesty.

Key Takeaways

  • Baseline first: Watch how someone acts when you already know they’re telling the truth, then look for shifts away from that baseline.
  • No single tell: Avoiding eye contact, fidgeting, and other individual cues are weak signals. None proves a lie on its own.
  • Polygraphs are unreliable: Lie detector tests measure stress, not lying itself, and produce a high rate of false positives.
  • Cognitive load helps: Asking someone to recount events in reverse order makes it harder to sustain a lie and easier to detect.
  • Trust your gut: Instinctive reactions can outperform conscious judgment, though even trained professionals rarely beat chance overall.

Establishing a Baseline

An example would include watching how the person responds to basic questions with straightforward answers like “What is your name” and “Where are you from?”

Pay attention to their eyes, and watch where they go. Notice how their voice sounds and look at their body language.

Once you have established a baseline and want to spot a lie, look for shifts in behavior.

Saul McLeod, PhD

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Chartered Psychologist (CPsychol)

Saul McLeod, PhD, is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Olivia Guy-Evans, MSc

BSc (Hons) Psychology, MSc Psychology of Education

Associate Editor for Simply Psychology

Olivia Guy-Evans is a writer and associate editor for Simply Psychology, where she contributes accessible content on psychological topics. She is also an autistic PhD student at the University of Birmingham, researching autistic camouflaging in higher education.

Mia Belle Frothingham

Author, Researcher, Science Communicator

BA with minors in Psychology and Biology, MRes University of Edinburgh

Mia Belle Frothingham is a Harvard University graduate with a Bachelor of Arts in Sciences with minors in biology and psychology