Humans are poor lie detectors, usually able to spot deception only a little better than by chance. Anne Eisenberg, in the article, Software that Listens for Lies (link here), reviews computer technology that does a much better job at detecting deception.
The old technology, the polygraph machine, does a reasonably good job in detecting physiological stress. The examiner asks for a number of truthful statements and a few lies to get a baseline. Then the real questioning begins. Unfortunately, it is relatively easy to fool the machine by consciously changing one's muscle tension and breathing. More reliable computer programs have come to the rescue. Variations of these programs have been used in the business world for some time. For example, companies that sell travelers checks may run a person's phone call through a software program to determine whether the "victim" really did "lose" the checks.
Eisenberg discusses the research of Hirschberg, Jurafsky, and Fitzpatrick and Bachenko. All of these scientists study language and deception and use the power of computers to key in on subconscious cues.
Hirschberg's research shows that the "person’s speech provides all the cues — loudness, changes in pitch, pauses between words, ums and ahs, nervous laughs and dozens of other tiny signs that can suggest a lie."
“The scientific goal is to understand how our emotions are reflected in our speech,” Dr. Jurafsky said. “The engineering goal is to build better systems that understand these emotions.”Similarly, Fitzpatrick and Bachenko "are using computers to automatically spot clusters of words and phrases that may signal deception."
Unfortunately, you and I can't figure out whether someone is lying by looking for a slight smile and avoidant look. We need the computer software. I look forward to the time when this software is available to the general public. Men and women will take their laptops with them on dates. Parents will tell their teenagers to speak into the microphone. Maybe we all will become a little more honest.