The Secret Life of Pronouns_ What Our Words Say About Us - James W. Pennebaker [70]
DETECTING DECEPTION: A LESSON IN REALITY
Having been connected to parts of law enforcement for much of my career, I’ve been impressed by the number of ridiculous claims people have made about detecting deception. Researchers with sterling reputations who have spent years studying the biological correlates of deception (such as those measured by the polygraph), nonverbal indicators of deception, the language of deception, and now the brain activity of deception have always come away with the same conclusions: We have a system that works much better than chance. No system has ever been shown to reliably catch liars at rates much higher than 65 percent. And even those with hit rates in that neighborhood (including me) have done so in highly controlled and artificial circumstances.
Nevertheless, I have heard over and over again about specific individuals or companies that claim to have a system that can catch deception 95 percent of the time. This is not possible. This will never happen in any of our lifetimes.
It is interesting that polygraph evidence is not allowed in the courtroom. The polygraph is actually impressive because it can accurately identify guilty people at rates close to 60–65 percent. Eyewitness identification, which is allowed in the courtroom, is probably accurate at comparable rates to the polygraph.
It is time that we begin to think about scientific evidence in the courtroom. Specifically, it is all probabilistic. If polygraph, nonverbal, eyewitness, brain scan, and any other type of evidence can help classify the guilt or innocence of a witness it should be introduced in court. However, it should be introduced in a way that calibrates its accuracy to the jury. Each type of evidence is simply something else for the jury to weigh, knowing that there are problems with each type. Life is probabilistic—courtroom evidence is no different.
LYING FOR LOVE: EVALUATING HONESTY IN POTENTIAL DATING PARTNERS
Deciding on whether to go on a date with someone doesn’t have the same gravitas as deciding if someone should go to prison for the rest of their lives. Leaving the prison metaphor aside, online dating sites can determine who you may live with the rest of your life. Deception in selecting a date and possibly a mate for life is serious business. And word on the street is that people are sometimes deceptive in terms of what they say about themselves online.
Just ask Jeff Hancock. Hancock and his colleagues at Cornell University conducted a riveting study with eighty online daters in the New York City area. The people—half male and half female—were selected based on their profiles on one of four commercial dating sites. All included a picture; information about their weight, height, and age; and a written description of who they were along with their interests. After agreeing to participate, each visited the research lab, where they completed several questionnaires. Their pictures were taken, their driver’s licenses scanned, and their height and weight measured.
As you can see, Hancock was able to determine how deceptive the daters’ online information was now that he had independently validated age (from the driver’s license), height, and weight. He was also able to get a group of raters to compare the photo he took in the lab with the one displayed on the online posting. Men tended to lie about their height and women their weight. Both sexes posted pictures that were flattering compared to their lab pictures—although some people’s online pictures were much more flattering than others. From all the objective information he collected, Hancock calculated a deception index for each person.
The heart of the research was to