You Really Can’t Trust What People Say About Themselves

The idea that everyone lies is generally well-accepted in the behavioral sciences. Plenty of evidence shows that, even without much incentive, people will avoid telling the truth. This is true when people are asked to provide information about themselves. Think about the last time you filled out a form for a medical visit. Did you honestly report the number of alcoholic beverages you have weekly or even your current weight?

This tendency to bend or completely avoid the truth may be a problem if you develop an illness that relies on this information. But it can also be problematic for psychology researchers whose evidence is based on self-report tests.

The Universal Tendency to Lie on Psychological Tests

Because it’s widely acknowledged that people will distort their responses on a self-report questionnaire, there is a way to check the degree to which this is occurring. Going back to the 1950s, social desirability scales ask people to state whether they would engage in a variety of common white lie situations, such as trying to get something for free or always checking the credentials of everyone they vote for.

But according to the University of Rotterdam’s Natacha Henriquez and colleagues (2026), lying in psychological tests may be even more extreme. “Supernormality” is the tendency to portray yourself as “someone completely free of anything that is remotely related to psychopathology” (p. 2). We can sniff this out on—guess what—a psychological self-report test. The Supernormality Scale Revised SS-R includes items that go beyond mere social desirability to determine whether a person refuses to admit to any common psychological symptoms at all (Cima and colleagues, 2003).

Although you’d be likely to think such culprits would be hardened criminals, the problem is actually common among student samples, according to Henriquez and colleagues. It’s even more extreme if the questions concern socially condemned or taboo behaviors.

The paradox, then, is that liars are more likely to lie and under-report any problematic behaviors. However, taking a more nuanced approach, the study’s authors make it a point to distinguish among the reasons that people lie. Liars might try to avoid embarrassment, conflict with a relational partner, and—more seriously—tell antisocial lies such as vindictive rumors. Again, though, adding complexity to the equation is “prolific liars” (6-11 percent according to previous research) who are virtually dripping in deceit. Most people lie more selectively.

Sniffing Out the Self-Report Liar

Using the SS-R, the Rottenberg research team set out to determine whether those who go beyond mere social desirability are more likely to “fake good” (lie to show they don’t lie) compared with so-called credible self-reporters. With a sample of 777 adults (average age 24 years), the researchers divided respondents into the credible and supernormal groups. They then compared them on a variety of measures involving self-reports of various lying behaviors. Credible people would, the theory is, admit to lying more than would the supernormal members of the sample.

To assess tendencies to lie in ordinary situations, the test instruments included a measure of overall lying (“I am a good liar”) and lying in everyday situations (“I lie to stay out of arguments with people”). Participants also completed a selection of items from a standard inventory of psychological symptoms intended to tap into the likelihood of reporting those symptoms that would be considered noncredible.

Overall, people tended to report low levels of lying, said they prefer not to lie, and felt guilty when lying. They were more likely to report lying in a relational context versus telling antisocial lies. However, comparing the two subgroups of credible versus supernormal participants, it was clear that the extent of reported lying was far greater in the credible group.

Assuming that impression management, or the desire to look good to others, sits at the root of supernormal responding, the authors concluded that the supernormal group in the sample did so “as a result of extreme impression management tendencies” (p. 5). Even though the supernormal group made up only 29 percent of the sample, the low-stakes, anonymous nature of the study suggests these participants have a strong drive to impress others or protect their self-image.

All of this would augur poorly for anyone conducting psychological research based on questionnaires, including self-reporting of symptoms. If liars underreport their lying, they will also underreport other problematic behaviors. The fix is not to give up on getting to the truth, but for researchers to include some form of control via a measure such as the SS-R. This goes beyond including social desirability measures, a common practice in the field.

Deception Essential Reads

Deceivers Come in Three Main Types

Frauds, Con Men, Liars, and Shame

Spotting the Supernormal Liar in Your Life

Countless sources of advice exist on detecting deception in ordinary social situations, ensuring you aren't taken advantage of by someone who doesn’t have your best interests at heart. The Rotterdam study adds to this advice by suggesting you need to detect the liar who never admits to lying.

You don't need to administer the entire SS-R, but you can look for certain cues such as whether a person claims, for example, to “have my problems under full control.” Or, “I’m never bored.” “I’m my own best therapist” would be another clue, but so would its reversed counterpart, such as “I still have to work on myself.” Be attuned to terms in the absolute that deny problems versus admitting to having the kind of ordinary experiences that people have when things aren’t always perfect.

To sum up, without some control, psychological researchers can have significant problems in figuring out what to do with their data. The average person, though, can also benefit from similar remedies to ensure that the people in their lives don’t just seem believable, but are.