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Getting Suckered by a Killer

policeHow many people must that mass murderer have fooled about who he was and what he was about to do before he went on a rampage and killed six people and injured many more? It happened just outside of the campus of UC Santa Barbara, the university I’ve been associated with for nearly 14 years.

I have to admit that when I heard that law enforcement personnel (four sheriff’s deputies, a police officer, and a dispatcher) had been sent to talk to the killer less than a month before his killing spree, my jaw dropped. The killer’s mother and therapist had both become disturbed by the videos he had been posting, and contacted the police to ask them to check up on him.

The deputies talked to him outside his apartment, and he reassured them that it was all a misunderstanding. They never went inside; if they had, they may have discovered a frightening cache of guns and ammunition. After they left, the officers described the soon-to-be-killer as “shy, timid, and polite.”

I’m here today (off-topic from my usual single-at-heart posts) to defend those deputies and officers who talked to the killer on that fateful night. I’m not defending their decision not to go inside, or not to look at the online videos. Whether they acted within the bounds of the current rules and procedures on those matters is for others to figure out.

What I am defending is the fact that, after a brief interaction with the person who was planning a mass murder, they walked away not the least bit suspicious of the person. He was lying, and they totally and completely failed to detect his lies.

Before I started studying of single life, I spend decades doing research on the psychology of lying and detecting lies. My colleagues and I reviewed every study ever conducted on people’s accuracy at detecting deception, and we found that people are amazingly unimpressive at knowing when other people are lying and when they are telling the truth, based just on what they say and how they say it (their verbal and nonverbal behavior). On the average, in situations in which people would get 50% right just by guessing, they typically get just 54% right.

Some have claimed that people in jobs that involve the detection of deception, such as police officers, are better at detecting deception than ordinary people. A colleague and I tested that possibility in a study of federal law enforcement officers, from those just starting out to advanced officers. The officers, including the advanced ones, were no better at detecting deception than the college students – they just thought they were. They had greater confidence, but no greater accuracy.

In many other studies, too, people in deception-relevant jobs are generally no better at detecting deception than people without such job-related experiences. Occasionally there is a study suggesting that people in a particular group are a bit better than others, but then the replication studies are not done or do not support the original findings.

Another question is whether you could train people, such as sheriff’s deputies, to be able to detect deception. Many attempts to train people to detect deception better have produced discouraging results. Some people, such as Paul Ekman, claim to be able to train people to detect deception at high levels of accuracy, but Ekman has never published any training studies so fellow scholars are unable to look closely at his work. A few studies here and there suggest one-time successes at improving deception-detection accuracy by training methods. Those studies need to be replicated, and then we need to know whether the accuracy at the types of lies and kinds of situations used in the training would generalize to, say, a group of sheriff’s deputies having a brief conversation with a college student outside of his apartment.

My bottom line: Don’t blame those officers for not knowing that the would-be killer was lying to them, just from talking to him for a short time. Hardly anyone is good at that, whether they are professionals in jobs that involve lie-detection on a day to day basis, whether they have gotten training, or whether they are just ordinary people. Lie-detection is hard in those situations, and fooling people is easy.

[Note: For more of my writings on deception, click here and here.]

Police image available from Shutterstock.

Getting Suckered by a Killer

Bella DePaulo, Ph.D

Bella DePaulo (Ph.D., Harvard; Academic Affiliate, Psychological and Brain Sciences, UC Santa Barbara), an expert on single life, is the author of several books, including "Singled Out: How Singles Are Stereotyped, Stigmatized, and Ignored, and Still Live Happily Ever After" and "How We Live Now: Redefining Home and Family in the 21st Century." Her TEDx talk is "What no one ever told you about people who are single," Dr. DePaulo has discussed singles and single life on radio and television, including NPR and CNN, and her work has been described in newspapers such as the New York Times, the Washington Post, the Wall Street Journal, and USA Today, and magazines such as Time, Atlantic, the Week, More, the Nation, Business Week, AARP Magazine, and Newsweek. Dr. DePaulo is in her sixties. She has always been single and always will be. She is "single at heart" -- single is how she lives her best and most meaningful life. Visit her website at

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APA Reference
DePaulo, B. (2014). Getting Suckered by a Killer. Psych Central. Retrieved on February 20, 2020, from


Last updated: 3 Jun 2014
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