Yes, nervousness can affect a lie detector test. A lie detector test, also known as a polygraph, is set up to detect autonomic responses, which detect involuntary body functions that are not under conscious control, such as heart rate and skin conductivity. The premise behind a lie detector test, or polygraph, is that a lie is associated with guilt, and guilt is associated with a stress response. This stress response is the adrenaline response, also known as the fight or flight response. The polygraph then detects changes in heart rate, respiration rate, blood pressure, and muscular movement. Increases in these variables after a question is asked may be interpreted as a guilt response to a lie, and the answer to this particular question may be interpreted as a lie, and not the truth.
The problem with polygraphs is that although they are good at detecting a stress response, other factors besides guilt from not telling the truth may be present, like having anxiety and nervousness. When you are nervous and anxious, you will set-off the stress response. In this stress response, also known as the fight or flight response, the anxiety triggers the amygdala (part of the brain) to signal the hypothalamus and the pituitary gland. A signal is then sent to the adrenal glands (which sit on top of the kidneys), and adrenaline (epinephrine) is released. This adrenaline response causes an increase in heart rate, respiration rate, blood pressure, and muscle tension. So if you have anxiety and nervousness during a polygraph, your answer to a question and your subsequent adrenaline response might be misinterpreted as guilt, and hence a lie on the polygraph. Being emotional can affect the results of your polygraph, as anger and surprise can also set off the adrenaline response, in addition to anxiety and guilt.
Truthful but failed says
I recently took a polygraph (that I suggested) to prove my innocence on something that happened 18 / 19 years ago. I did it for a TV show, “Face The Truth”. I have a cyberbully and the only thing she keeps bringing up is the past. She has never moved forward or on.
Every time I hear her name, or even talk about her, I get anxious. Her and money are the only thing I get anxiety over. I answered the test honestly and truthfully and I still ended up as “lying” or failing the test. I was shocked when they announced it…in front of her.
Now she is attacking me on social media about it. I can’t take anymore. I don’t know how to calm my anxiety so that I can take another test. Do you have any suggestions?
Dr. Carlo says
Ask your doctor to prescribe you something short-term, like a benzodiazepine, to calm you down right before the polygraph. You would take such pill about 1 hour before the polygraph, to give you a few hours of calm.
James wible says
Would like your input. I have PTSD had to take a polygraph I answered truthfully. I’ve been reading that my PTSD n serve a anxiety. Would affect the out come of the polygraph when I know I told the truth.
Dr. Carlo says
Baseline anxiety will likely produce false-positive results on the polygraph.
Is there any research available on this topic? Is there a link between anxiety disorders and false-positive polygraph results?
I take regular scheduled polygraphs, and have been diagnosed with Anxiety, Paranoia and ADHD. I have field my last two Polys even though I was being completely honest. The Poly tester swears to the heaves that none of these issues can interfere with the test. where can I get documentation to prove to him that it is the issues and not me lying?
Dr. Carlo says
There’s no way to prove this…it’s still a subjective process, this lie detector test.