Revisiting Nonverbal Behavior
We have shown that nonverbal behavior is crucial to detecting deception, but it seems that our previous discussions have been a little insufficient.
Certainly this has been a major discussion in this blog, but we have focused only on individual behaviors, like eye contact or gestures, in order to explain how important nonverbal behavior is. However, as new research by Dr. David Matsumoto and Dr. Hyisung Hwang demonstrates, clusters of multiple behaviors may be even more important.
In their forthcoming study, Drs. Matsumoto and Hwang build on previous research suggesting that focusing on a given individual nonverbal behavior is enough. They point out that lying depends on the maintenance of emotional states which help us continue our deception. This generally requires that we internalize additional emotions, corresponding to the increased cognitive work that lying requires.
While any individual nonverbal behavior may fade far too quickly to notice, a series of nonverbal behaviors born out of these additional emotions can last much longer, making lie detection easier. The goal of this study was to attempt to isolate deceptive behaviors and to see if certain patterns of nonverbal behavior tended to correspond with deception.
They hypothesized that patterns of nonverbal behaviors would reliably indicate deception and also that more open-ended interrogations would produce a greater amount of indicative nonverbal behaviors.
In order to answer these questions, they recruited a sample of students from various ethnic backgrounds and, after some initial assessments, divided them randomly into two groups. The first group was told they would be gifted a $100 check, while the second was told they could look at but not take the same $100.
The participants were eventually given the opportunity to steal the check, after which they were told that they had been “randomly” selected for an interview. Interestingly, each of them had been previously instructed to make a point of proving their honesty, regardless of their guilt. This is where the article’s data collection truly began.
The researchers employed interrogation tactics modeled after actual law enforcement techniques and utilized of a variety of open and closed ended questions, in order to test the second hypothesis. During this process, they tracked facial expressions and other nonverbal behavior like head movements and gestures.
Overall, the experiment demonstrated broad support for both hypotheses. They found that when participants lied, they produced a lower pitch in the voice and engaged in fewer head nods, which Drs. Matsumoto and Hwang suggest may be due to greater levels of emotion on the part of the deceiver.
These findings may set a new direction for research into deception detection and nonverbal behavior. Rather than just focusing on a specific feature, it is important to understand how larger underling emotional states can create persistent changes in behavior.
Naturally, this might be a bit much for any of us to keep in our head, so it may help you out to get some professional advice on properly detecting deception!