6 Myths About Personality Tests That Need to Die

Personality tests sit in a strange cultural position. Some people treat their results as sacred truth, defining their identity around four letters or a trait label. Other people dismiss all personality assessment as pseudoscience on par with horoscopes. Both positions are wrong, and both come from the same place: myths about what personality tests are, what they do, and what the science behind them actually says.

Here are six myths that keep circulating, and the research that debunks them.

Myth 1: Personality Tests Are Just Horoscopes With Better Marketing

This is the most common dismissal, and it conflates very different things.

Horoscopes assign personality descriptions based on birth date, with no validated mechanism connecting celestial positions to human behavior. There is no predictive validity. Multiple controlled studies have shown that people cannot distinguish their own horoscope from randomly assigned ones at rates better than chance (Shawn, Carlson, 1985).

The Big Five personality model, by contrast, is based on factor analysis of how people actually describe themselves and others. The five factors emerged from statistical patterns in language and behavior, not from theory imposed top-down. They have been replicated across 50+ cultures (McCrae & Costa, 1997), predict real-world outcomes with measurable effect sizes (Roberts et al., 2007), and have test-retest reliability above .80 for well-constructed assessments (Costa & McCrae, 1992).

The distinction is not subtle. Horoscopes are unfalsifiable narrative. The Big Five is a measurement instrument with known validity and reliability coefficients. Dismissing all personality tests because bad ones exist is like dismissing all medical tests because blood-type personality theory is pseudoscience.

Myth 2: You Can Cheat a Personality Test

Many people believe they can game their results by answering strategically, choosing the "right" answers to get a desired profile.

You can, in theory, answer dishonestly. But research on impression management in personality testing shows that most people, even when motivated to present well (like in job applications), shift their scores by less than half a standard deviation, and trained psychologists can detect this shift using validity scales built into well-designed assessments (Ones, Viswesvaran, & Reiss, 1996).

More importantly, when you take a personality test for self-knowledge (not for a job application), cheating only hurts you. The test is a mirror. Answering strategically just gives you a distorted reflection. You already know what you wish your personality looked like. The value of a well-made assessment is showing you what your personality actually looks like, including the parts you've been avoiding.

Myth 3: Your Personality Type Is Fixed for Life

The idea that "you're born an introvert and die an introvert" is widely believed and mostly wrong.

The Big Five traits are relatively stable over time, which is not the same as fixed. A meta-analysis of 92 longitudinal studies found that personality changes meaningfully across the lifespan (Roberts, Walton, & Viechtbauer, 2006). The general pattern is toward maturity: Conscientiousness and Agreeableness increase with age, Neuroticism decreases, and Openness and Extraversion show smaller, more variable changes.

These changes are not trivial. The average person's personality changes as much between age 20 and 60 as the difference between two randomly selected people (Roberts & Mroczek, 2008). You are measurably different at 40 than you were at 20.

Deliberate change is also possible. A 2017 meta-analysis found that therapeutic interventions produce measurable personality change, particularly reductions in Neuroticism, in as little as four to eight weeks of treatment (Roberts et al., 2017). The change tends to persist after treatment ends.

Myth 4: There Are Only a Few "Types" of People

The idea that humanity can be sorted into 4, 9, 16, or any fixed number of types is appealing because it simplifies an overwhelmingly complex reality. But the research does not support it.

Taxometric analyses, statistical tests designed to determine whether data is categorical (types) or continuous (spectra), consistently find that personality traits are dimensional, not categorical (Haslam, Holland, & Kuppens, 2012). People do not cluster into distinct groups. They spread across continuous distributions on each trait.

This is why the Big Five uses spectrum scores rather than type labels. You are not "an introvert" or "an extravert." You are somewhere on the Extraversion spectrum, and where you fall tells you more than which side of the midpoint you landed on.

Type-based systems (like the 16 types) can be useful as conversational shorthand, but they sacrifice accuracy for simplicity. The real structure of personality is dimensional, and treating it as categorical throws away information.

Myth 5: Online Personality Tests Are All Garbage

Many of them are. But not all, and the distinction matters.

The IPIP-NEO (International Personality Item Pool), which is the basis for most serious free Big Five assessments online, was developed by Lewis Goldberg and colleagues using the same psychometric standards as commercial instruments (Goldberg et al., 2006). Studies have found that the IPIP-NEO produces results that correlate at .85-.94 with the commercial NEO PI-R, which is the gold-standard clinical instrument (Maples et al., 2014).

The key differences between a good online test and a bad one:

• Item count: Reliable Big Five measurement requires at least 60 items (the IPIP-NEO-120 uses 120). Tests with 10-20 items sacrifice reliability for speed.
• Norming: Good tests compare your scores to a normed sample (adjusted for age and gender). Bad tests just give you raw scores or vague descriptions.
• Facets: Good tests report facet-level scores (6 per dimension, 30 total). Bad tests only report the 5 broad dimensions.
• Source: Good tests cite their psychometric properties. Bad tests cite nothing.

A 120-item assessment with facet scoring and normed percentiles, taken honestly and without time pressure, produces clinically comparable results whether administered online or in a psychologist's office.

Myth 6: Personality Tests Put You in a Box

This is the most philosophically interesting myth, and it reveals a genuine tension.

People worry that knowing their personality scores will limit them, that they will use the results as excuses ("I can't do that, I'm too introverted") rather than as information. This is a real risk, but it is a risk of how people use the information, not a flaw in the information itself.

Research on self-knowledge suggests the opposite pattern. People who have accurate self-perception make better decisions about their environments, relationships, and goals (Dunning, Heath, & Suls, 2004). They are less likely to commit to things that drain them and more likely to invest in situations that fit their actual tendencies.

A personality test does not put you in a box. It describes the box you have been living in without realizing it. The awareness is what gives you the option to expand it, reinforce it, or redesign it entirely.

The quality gap between the best and worst personality tests is enormous. Dismissing all personality assessment because BuzzFeed quizzes exist is like dismissing all medicine because homeopathy exists. The rigorous instruments work. They have been tested, validated, and replicated across thousands of studies.

The question is not whether personality tests are legitimate. It is whether you are taking a good one.

Take a good one. The Big Five personality assessment is based on the IPIP-NEO-120, with full facet scoring and peer-reviewed norms. It takes about 15 minutes, the results are free, and it measures what it claims to measure.

References

• Carlson, S. (1985). A double-blind test of astrology. Nature, 318, 419-425.
• Costa, P. T., & McCrae, R. R. (1992). Revised NEO Personality Inventory professional manual. Psychological Assessment Resources.
• Dunning, D., Heath, C., & Suls, J. M. (2004). Flawed self-assessment: Implications for health, education, and the workplace. Psychological Science in the Public Interest, 5(3), 69-106.
• Goldberg, L. R., et al. (2006). The International Personality Item Pool and the future of public-domain personality measures. Journal of Research in Personality, 40(1), 84-96.
• Haslam, N., Holland, E., & Kuppens, P. (2012). Categories versus dimensions in personality and psychopathology. Psychological Medicine, 42(5), 903-920.
• Maples, J. L., et al. (2014). A test of the IPIP representation of the NEO PI-R. Journal of Personality Assessment, 96(4), 348-359.
• McCrae, R. R., & Costa, P. T. (1997). Personality trait structure as a human universal. American Psychologist, 52(5), 509-516.
• Ones, D. S., Viswesvaran, C., & Reiss, A. D. (1996). Role of social desirability in personality testing for personnel selection. Journal of Applied Psychology, 81(6), 660-679.
• Roberts, B. W., et al. (2007). The power of personality. Perspectives on Psychological Science, 2(4), 313-345.
• Roberts, B. W., et al. (2017). A systematic review of personality trait change through intervention. Psychological Bulletin, 143(2), 117-141.
• Roberts, B. W., & Mroczek, D. (2008). Personality trait change in adulthood. Current Directions in Psychological Science, 17(1), 31-35.
• Roberts, B. W., Walton, K. E., & Viechtbauer, W. (2006). Patterns of mean-level change in personality traits across the life course. Psychological Bulletin, 132(1), 1-25.