Chapter 8. Lie Detection

8.1 Welcome

Think Like a Scientist
true
Confirmation bias
The tendency to seek out evidence that confirms an existing belief while ignoring evidence that might contradict or undermine the belief.
independent variable
The purposely manipulated factor thought to produce change in an experiment.
dependent variable
The factor that is observed and measured for change in an experiment, thought to be influenced by the independent variable.

Think Like a Scientist

Lie Detection

By:

Susan A. Nolan, Seton Hall University

Sandra E. Hockenbury

REFERENCES

Bond, Charles F., & DePaulo, Bella M. (2006). Accuracy of deception judgments. Personality and Social Psychology Review, 10, 214–234.

Frank, Mark G., & Feeley, Thomas Hugh. (2003). To catch a liar: Challenges for research in lie detection training. Journal of Applied Communication Research, 31, 58–75.

Hauch, Valerie; Sporer, Siegfriend L.; Michael, Stephen W.; & Meissner, Christian A. (2014). Does training improve the detection of deception? A meta-analysis. Communication Research, 0093650214534974.

Nickerson, Raymond S. (1998). Confirmation bias: A ubiquitous phenomenon in many guises. Review of General Psychology, 2, 175–220.

Porter, Stephen, & ten Brinke, Leanne. (2010). The truth about lies: What works in detecting high‐stakes deception? Legal and Criminological Psychology, 15, 57–75.

Smith, Jonathan C. (2010). Pseudoscience and extraordinary claims: A critical thinker’s toolkit. Malden, MA: Wiley-Blackwell.

FAQ

What is Think Like a Scientist?
Think Like a Scientist is a digital activity designed to help you develop your scientific thinking skills. Each activity places you in a different, real-world scenario, asking you to think critically about a specific claim.

Can instructors track your progress in Think Like a Scientist?
Scores from the five-question assessments at the end of each activity can be reported to your instructor. To ensure your privacy while participating in non-assessment features, which can include pseudoscientific quizzes or games, no other student response is saved or reported.

How is Think Like a Scientist aligned with the APA Guidelines 2.0?
The American Psychological Association’s “Guidelines for the Undergraduate Psychology Major” provides a set of learning goals for students. Think Like a Scientist addresses several of these goals, although it is specifically designed to develop skills from APA Goal 2: Scientific Inquiry and Critical Thinking.
“Lie Detection” covers many outcomes, including:

  • Use scientific reasoning to interpret psychological phenomena: Describe common fallacies in thinking that impair accurate outcomes and predictions. [consider confirmation bias]
  • Demonstrate psychology information literacy: Articulate criteria for identifying objective sources of psychology information. [compare journal articles and online ads]

8.2 Introduction

This activity invites you to test the claim that lie detection skills can be improved with training. First, you will test your own lie detection skills by guessing which people in a series of videos are lying. You will explore the evidence, as outlined in a meta-analysis by psychologists Charles Bond and Bella DePaulo (2006), on how successful people tend to be in detecting lies in everyday life. You will receive instructions that some people have used in efforts to improve their lie detection skills. You will then have another opportunity to test your own lie detection skills. You’ll examine alternative explanations for your beliefs about your own lie detection abilities. Finally, by comparing two sources of information, online ads and published peer-reviewed journal articles, you will explore whether training can improve lie detection ability.

8.3 Identify the Claim

1

Identify the Claim

8.3.1 Who Is Lying?

A saleswoman adjusts an outfit on a young woman. The buyer should understand the tactics imposed by salespeople to increase sales.
moodboard / Alamy

Wouldn’t you like to know if someone is lying to you? We know people lie to us sometimes, but do we typically know when we’re being lied to? Are these people lying—the person who declines your party invitation because she says she is too busy, the lab partner who claims he lost his work because his computer died, or the salesperson who tells you that the new outfit you’re trying on looks fantastic on you?

8.3.2 Lie Detection Training

None of us is a perfect lie detector. If we were, no one would be able to get away with lying! Whether you think you are good or bad at detecting lies, you probably would like to get better at it. Many Web sites offer training programs to improve your lie detection ability. Look at this mock ad, developed from actual Web sites for lie detection programs. (Click image to enlarge.)

The photo shows a mock webpage entitled Lie Detect that claims to improve users’ lie detection abilities.
Charlotte Purdy/Shutterstock Jean Valley/Shutterstock

Question

rqZaYoBUExXLV7sWffVJbcYQD2PwRqFpkMRfg3vN9cHPihxp8doZeCYticSXbszYvmL42p6s8TTD+xLgPIBMbsnLndwErCjILrPcgGBx3iYsK2tkUUBftw==
The ad claims that people who complete a $79 training module can improve their ability to detect lies, increasing their accuracy rates from 54% to 90%.

8.4 Evaluate the Evidence

2

Evaluate the Evidence

8.4.1 Are People Naturally Good at Detecting Lies?

Two young women talk to each other, and one woman has a doubtful expression on her face,which represents that the other person might be lying.
Yellow Dog Productions/Getty Images

In order to test whether training can improve our ability to detect lies, first we must know how good we naturally are at catching liars. If we wanted to conduct an experiment, the independent variable would be the presence of training—no training versus training. The dependent variable is what we measure. In this case, it would be the accuracy rate. Let’s look at your accuracy rate without training.

Question 8.1

What percentage of the time do you think most of us accurately detect liars? sPv9h3Pnsgn+QwLP%

Correct.
Incorrect.

8.4.2 Are You Naturally Good at Detecting Lies?

{true} setModel("numCorrect", 0)

You guessed that most people have an accuracy rate of No response entered. % in detecting liars. Let’s see how accurately you guess which of these people are lying or telling the truth in the following eight videos. (You can click to make the videos full screen. And don’t be afraid to guess! Only responses to questions in the assessment section of Think Like a Scientist activities may be shared with your instructor. Your responses here are just for you.)

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{true} setModel("numCorrect", model.numCorrect + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

nVRvXMtvXq9TqY7cs1//zVe/FBxLaDqAwhZpaw==
{true} setModel("numCorrect", model.numCorrect + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{true} setModel("numCorrect", model.numCorrect + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{true} setModel("numCorrect", model.numCorrect + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

nVRvXMtvXq9TqY7cs1//zVe/FBxLaDqAwhZpaw==
{true} setModel("numCorrect", model.numCorrect + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{true} setModel("numCorrect", model.numCorrect + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{true} setModel("numCorrect", model.numCorrect + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

nVRvXMtvXq9TqY7cs1//zVe/FBxLaDqAwhZpaw==
{true} setModel("numCorrect", model.numCorrect + ((qq1 == true) === true ? 1 : 0))

8.4.3 Lie Detection Research

{true} setModel("percentCorrect", ( player.model.numCorrect / 8 * 100).toFixed(1))

You correctly identified who was lying and who was telling the truth {model.percentCorrect}% of the time. Is that typical? Let’s look at the research on how people actually do. Psychologists Charles Bond and Bella DePaulo (2006) examined research from more than 200 separate studies that looked at the judgments of more than 240,000 people.

In many of these studies, researchers asked participants to guess whether people in videos were telling the truth or lying, much like you just did. A rate of 50% would be just at the level of chance—that is, even if you closed your eyes, blocked your ears, and just guessed, you’d be accurate 50% of the time. Across all of these studies, people were accurate 54% of the time. As you can see in the accompanying graph, 54% is barely better than chance. We’re just not very good at catching liars.

A bar chart entitled with “Chance” has 0 to 100 percent labelled on its vertical axis with intervals of 50percentage points, where the blue colored bar on the horizontal axis reaches up to 50 percent of the vertical axis. Another bar chart entitled “Lie detection rate without training” has 0 to 100 percent labelled on its vertical axis with intervals of 50 percentage points, where the blue colored bar on the horizontal axis reached up to 54percent of the vertical axis.

8.4.4 Test the Claim: Does Training Improve Accuracy?

Many sources, like the Web site shown at the beginning of this activity, promise to make you a better lie detector. That ad claimed it could increase your accuracy rate from 54%, which we now know is the natural rate, to a nearly perfect 90%! Let’s learn one of the strategies promoted by lie detection training programs and then test it out to see how well it works. Training programs commonly claim that you can improve accuracy by paying attention to the following signals. Please read them carefully because you will have a chance to try them out on the next screen.

  • Signs of “mental effort,” such as a lower than normal level of eye contact
  • Nervous movements, such as picking at fingernails or clothing
  • Increased blink rate
  • Increased use of filler phrases, such as “you know” or “and so on,” which give the speaker time to think
  • Signs of tension or anxiety, such as perspiration or rapid breathing

Now let’s test the claim.

8.4.5 Did Training Help?

{true} setModel("numLying2", 0)
{true} setModel("correct2", 0)

Now try guessing again with eight more videos. (Click to make the videos full screen.) Which people are telling the truth, and which are lying? This time watch for the signals that the training programs claim are indications of deception, such as how much the people in the videos look at the camera—that is, make eye contact with the interviewer. In the next screen we will examine evidence that tests this claim.

Video Box

Question

nVRvXMtvXq9TqY7cs1//zVe/FBxLaDqAwhZpaw==
{qqMC1 == 0} setModel("numLying2", model.numLying2 + 1)
{true} setModel("correct2", model.correct2 + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

nVRvXMtvXq9TqY7cs1//zVe/FBxLaDqAwhZpaw==
{qqMC1 == 0} setModel("numLying2", model.numLying2 + 1)
{true} setModel("correct2", model.correct2 + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

nVRvXMtvXq9TqY7cs1//zVe/FBxLaDqAwhZpaw==
{qqMC1 == 0} setModel("numLying2", model.numLying2 + 1)
{true} setModel("correct2", model.correct2 + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{qqMC1 == 0} setModel("numLying2", model.numLying2 + 1)
{true} setModel("correct2", model.correct2 + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{qqMC1 == 0} setModel("numLying2", model.numLying2 + 1)
{true} setModel("correct2", model.correct2 + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{qqMC1 == 0} setModel("numLying2", model.numLying2 + 1)
{true} setModel("correct2", model.correct2 + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

+BSsZZMvajO5OluhWspwwZokYVnicPx4VNHhaQ==
{qqMC1 == 0} setModel("numLying2", model.numLying2 + 1)
{true} setModel("correct2", model.correct2 + ((qq1 == true) === true ? 1 : 0))

Video Box

Question

nVRvXMtvXq9TqY7cs1//zVe/FBxLaDqAwhZpaw==
{qqMC1 == 0} setModel("numLying2", model.numLying2 + 1)
{true} setModel("correct2", model.correct2 + ((qq1 == true) === true ? 1 : 0))

8.4.6 Lie Detection Training: The Research

{true} setModel("percentCorrect2", ( player.model.correct2 / 8 * 100).toFixed(0))
{Number( model.percentCorrect2 ) < 49 } setModel("feedbackText", 'This score is worse than what you would expect by chance.')
{Number( model.percentCorrect2 ) >= 49 && Number( model.percentCorrect2 ) <= 54 } setModel("feedbackText", 'This score is essentially the same as chance.')
{Number( model.percentCorrect2 ) >= 55 } setModel("feedbackText", 'You scored higher than we would expect. However, research would suggest that if you were tested on another ten videos, your overall accuracy rate would drop.')
A young woman thinks deeply,perhaps about the accuracy of lie detecting programs.
Credit: PhotoAlto/Milena Boniek/Getty Images

Do people get better at lie detection after training? Even with training, the average accuracy rate is still only about 54%—in other words, no better than the accuracy rate without training.

Why doesn’t training improve people’s abilities to detect lies? First, research shows that no single behavior consistently and reliably indicates that a person is lying—or telling the truth (Porter & ten Brinke, 2010). Second, the kind of training required to provide even small to moderate improvement is very sophisticated and requires longer, repeated sessions that cover a wide range of complex behaviors (Frank & Feeley, 2003; Hauch & others, 2014). And even then, the effect is highly variable—nothing like the enormous effect that the ads claim will result from their training.

So how did you do? You got {model.correct2} correct, giving you an accuracy rate of {model.percentCorrect2}%.

{model.feedbackText}

8.5 Consider Alternative Explanations

3

Consider Alternative Explanations

8.5.1 Confirmation Bias

Research shows that there are no consistently reliable markers of lying. So, why would we believe a claim that we can learn to detect lies? Despite the fact that we are not that good at detecting liars, many of us think we are. This is part of what makes us hopeful that we can become even better through training—and what may make us believe we are improving even when we are not.

Why do we overestimate our ability to detect liars? This is a good example of confirmation bias (Nickerson, 1998; J.C. Smith, 2010). We tend to notice and remember situations that confirm our belief that we are good lie detectors—and ignore or forget situations that don’t. So, we remember the time we caught a friend lying; it’s memorable that we bumped into her out with other friends when she said she was studying! But we don’t remember the times when we didn’t catch someone, or verified a friend was actually telling the truth.

Four people talk in a group, and they may be measuring the truthfulness of each other’s remarks.
luminaimages/Getty Images

8.6 Consider the Source of the Research or Claim

4

Consider the Source of the Research or Claim

8.6.1 Advertiser Versus Academic

Think about which source of information about lie detection is likely to be more reliable - an ad or an academic journal article. In the next screen, we'll talk about some of the differences. But first, look at the ad for lie detection training and a journal article addressing that topic.

Earlier, we noted that the ads claim that training is enormously successful at improving lie detecting accuracy. Recall that our mock ad referred to “studies” and claimed that “Even beginners will improve their lie detecting accuracy rate from 54% to 90%.”

The photo shows a mock webpage entitled Lie Detect that claims to improve users’ lie detection abilities.
Charlotte Purdy/Shutterstock Jean Valley/Shutterstock

Research articles also refer to other studies supporting their claims, and include data to demonstrate their results. According to the abstract, or brief summary, this journal article gives an overview of lie detection research. For example, it includes information about how well various nonverbal cues indicate when someone is lying.

The photo of a journal article entitled “The truth about lies: what works in detecting high-stakes deception?” provides information about how well various nonverbal cues indicate when someone is lying.

Question

ncx6SiIBlLzs+69c9r7ZoassQzJ+UzuSZXMTkCla60WzRAsHm5U3CftyDTA+Ezf4OCWt+gR5GJMP8aYrXhZucbiFaXJsiK+oLtyuxhbQKidjNkAU0oqKcQCbKGM/ElWn
Correct.
Incorrect. In the next screen, we’ll find out why.

8.6.2 Source: Online Ad

Well-designed Web sites that include impressive-sounding statistics, testimonials, and eye-catching designs are developed to catch our attention. But that doesn’t mean they are our best source for accurate information. The Web site doesn’t list any scientific sources for its assertions; it just refers to “studies” but doesn’t give any detail. In addition, the course developer is described as a “behavioral investigator” with no information about his educational or scientific background. Most importantly, we know that the purpose of this online course is to make money, which means that there is likely a powerful bias fueling the message that training is enormously effective. This message is likely an exaggeration.

The photo of the Lie Detect webpage highlights the nonscientific evidence that the site provides.

8.6.3 Source: Academic Journal Article

The journal article doesn’t seem to suffer from these biases. Good researchers list their academic institutions along with any funding sources or conflicts of interest. This article was written by Stephen Porter and Leanne ten Brinke, both professors at the University of British Columbia Okanagan. Good research is also published in peer-reviewed journals. That means other scientists have examined the research and found it to be well done. This article appeared in the journal Legal and Criminal Psychology which is published by the British Psychological Society. Although certainly every one of us has biases that can affect our thoughts and behaviors, there is no indication that any particular incentives would influence Porter and ten Brinke’s conclusions.

So, next time you see an online ad—for lie detection, weight loss, or improved memory—ask the right questions, examine the sources, and think like a scientist!

The photo of the journal article“The truth about lies: what works in detecting high-stakes deception?” supports the scientific study.

8.7 Assessment

Assessment

8.7.1 Assessment

Question

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The answer is B because Jenny most likely is remembering instances that fit with her belief that she is good at detecting lies.

Question

BBBDAHLGCKspcccBUt82zxZdDquOj6mCqSPQtdmUQIZtigIxVnzCOyDkmB874SjTZLNW0g/etLjAxjm4Mn+qsfrWBF8gDroYN1XNBMkcgMts5ie4WI42RRu9Ykqgeg4QiBTwJXxjMeqPDiLMbcFfapxXJ55To3/1cuUIuIyX8hoGbKSM9v6ZTRznw7LEQb/TcedM3FhaAgPUojDU98m/g57loEEMKFDWTPJg5gow9S3wgprSGae1EaaUJk3ZrJ/biWYe7JMX6dDAgWGBozeDdyeOQmw+EyipI1FxN+7ZRkxa5K93aah47LgTOwp7inTBFFcFOTFvNhXn8QYudc2pSEcBHygYl3Rdnzh9elqMDLpMxTXRAwzD/Xyatba/Ka85ZpLcO4X7pgIZT1b2FPBz0HQE7tXwHk1JnMmgXKCP5iYsXGzVeFpGwxZgr8PsxyFimCaLkD7tLUo2Ew1vumlmt9UTlE286ld+133ZYSS8piQ8B2PcOrNLk/xE+TljpIKaISZURW0SFi90c2YBkE4t+KaM2wE=
The answer is B because research has shown that training does not improve lie detection ability in most cases.

Question

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The correct answer is C, because research has shown that training does not improve lie detection ability.

Question

A photo of a webpage that advertises a product named Bfitness and provides no proven scientific evidence about its claims.
Tish1/Shutterstock (top left) Bevan Goldswain (top right) NinaMalyna/Shutterstock (bottom)
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
D is correct. Testimonials and vague, unsubstantiated claims are not scientific evidence.

Question

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The answer is D because the information is based on research published in peer-reviewed journals.