Overclaiming: Why People Claim Knowledge They Don’t Have

Asked to rate their familiarity with topics, a substantial proportion of survey respondents claim they understand concepts that don’t exist. Paulhus and Harms (2004), in Intelligence, demonstrated this empirically using a clever measurement procedure: present a list of real and fictitious items, ask respondents to rate their familiarity, and measure how many fictitious items they claim to know. The percentage of fake items endorsed — the “overclaiming index” — turns out to be a stable individual difference that predicts a range of personality and cognitive outcomes, including a counterintuitive positive correlation with self-reported confidence and competence.

Recent research has extended this measurement framework to large-scale international samples and to specific real-world consequences. Jerrim, Parker, and Shure (2023), analyzing PISA data from over 40,000 teenagers across nine Anglophone countries, documented systematic cross-national variation in overclaiming, gender differences, and substantial correlations with self-perception of effort, persistence, and social standing. Pennycook and colleagues (2020), in Journal of Personality, found that overclaiming predicts who falls for fake news — independent of analytic-thinking ability and political ideology. Across these studies, overclaiming emerges as a coherent psychological phenomenon with measurable individual differences and real-world consequences for decision-making, learning, and information consumption.

How overclaiming is measured

The Paulhus and Harms (2004) overclaiming technique works by exploiting a structural fact about real knowledge tests: a respondent who genuinely knows the material has a way of distinguishing real concepts from fake ones; a respondent who does not have to guess. The measurement procedure inserts plausible-sounding but fictitious items into a familiarity-rating list. A typical English-vocabulary instance might mix real terms (kafkaesque, panacea, simulacrum) with carefully constructed fakes (pavellic, retroplex, ultragesta). Respondents rate familiarity with each item on a 0-to-7 scale.

The accuracy index reflects how well respondents distinguish real from fake; the bias index reflects how generously they claim familiarity overall. The overclaiming score — endorsements of fake items — captures the tendency to assert knowledge without ground. Critically, this is not the same as random guessing or response carelessness; overclaiming is correlated across domains within a respondent (people who overclaim in one knowledge area tend to overclaim in others) and remains stable across testing occasions. It is a real individual-difference variable.

The measurement framework has been applied to vocabulary, science knowledge, mathematical concepts, historical events, and product brand familiarity. Bensch, Paulhus, Stankov, and Ziegler (2014), in Educational and Psychological Measurement, applied the technique to Scholastic Assessment Test (SAT) preparation contexts, finding that overclaiming on academic-content items added incremental predictive validity beyond the standard performance scores. The pattern across studies is robust: overclaiming is measurable, stable, and meaningful.

What overclaiming correlates with

The personality and cognitive correlates of overclaiming sketch a coherent profile. Overclaiming is positively correlated with:

• Self-reported competence and confidence in the same domain. People who overclaim in knowledge are also likely to rate themselves as knowledgeable; the two go together.
• Narcissism and grandiosity measures, particularly the “grandiose” or non-vulnerable forms. The overclaiming pattern fits a self-presentation theme.
• Bullshit receptivity — the tendency to rate vacuous pseudo-profound statements as deep or meaningful (Pennycook et al., 2020 documented the cross-correlation explicitly).
• Susceptibility to fake news, particularly fake news that aligns with prior beliefs.

Overclaiming is more weakly correlated with general cognitive ability. Higher-IQ individuals overclaim somewhat less than lower-IQ individuals, but the protection is modest (correlation magnitudes typically 0.20-0.30). The pattern fits the broader rationality literature: cognitive ability provides partial but incomplete protection against systematic biases in self-assessment.

Cross-cultural and demographic patterns

Jerrim, Parker, and Shure (2023) used the PISA framework to test how overclaiming patterns vary across countries, gender, and socioeconomic status. The PISA dataset administered overclaiming-style items on mathematical concepts to over 40,000 teenagers across nine Anglophone countries (US, UK, Ireland, Canada, Australia, New Zealand, plus several others), allowing for unusual statistical power on cross-national comparisons.

The headline findings: overclaiming rates varied substantially across countries, with U.S. teenagers showing notably higher rates than peers in several other countries. Gender differences were robust — boys overclaimed more than girls in nearly all countries — and the gap was larger in some cultural contexts than others. Socioeconomic status interacted with overclaiming in complex ways: higher-SES students were sometimes more likely to overclaim, particularly in knowledge-aspirational domains, but the pattern was inconsistent across countries.

Within-individual, overclaiming students were also more likely to report themselves as hard-working, persistent, and socially popular — even after controlling for actual academic performance. The overclaiming-confidence correlation persists across cultures and shows up in self-reports of personality traits well beyond the specific knowledge claims being measured.

Why people overclaim

Several mechanisms plausibly contribute to overclaiming. The simplest is impression management — overclaiming is a low-effort way to present oneself as knowledgeable, particularly in social or evaluative contexts. The Jerrim 2023 finding that overclaiming correlates with self-reported social popularity is consistent with this account: students who overclaim may also use overclaiming-like strategies in everyday social interactions.

A second mechanism is genuine self-deception. People may not be deliberately misrepresenting their knowledge; they may actually believe they understand concepts they do not. This is the more interesting psychological account, and it connects overclaiming to the broader literature on metacognition and the Dunning-Kruger effect: people who lack ability often lack the meta-cognitive resources to recognize what they don’t know.

A third mechanism, particularly relevant for the Pennycook fake-news findings, is reduced epistemic vigilance. People who overclaim may be operating with looser standards for what counts as knowing — accepting plausible-sounding claims without the careful evaluation that distinguishes real concepts from fictitious ones. The same loose standards make them more susceptible to fake news, conspiracy theories, and pseudoscientific claims.

These mechanisms are not mutually exclusive. Overclaiming likely reflects a mix of self-presentation strategy, genuine metacognitive miscalibration, and reduced epistemic vigilance, with different mixtures dominating in different individuals and contexts.

Practical implications

For educators: overclaiming is one component of student self-assessment that does not directly track real knowledge. A student who claims confidence about a topic may be overclaiming rather than reporting calibrated competence, and educational interventions that rely on student self-assessment should account for the systematic bias. Direct testing remains the more reliable measure of what students actually know.

For information consumers: the Pennycook 2020 finding that overclaiming predicts fake-news susceptibility has direct implications for media literacy. Recognizing one’s own propensity to overclaim — to accept plausible-sounding claims without careful evaluation — is part of the skill of being a discerning information consumer. Targeted interventions that train epistemic vigilance, particularly around evaluating source credibility and claim plausibility, are more effective than generic “be skeptical” appeals.

For self-assessment generally: the empirical evidence is that self-reported knowledge or competence is partly a measure of overclaiming rather than calibrated self-knowledge. People should weight their own confidence reports against external indicators (test performance, expert evaluation, behavioral evidence) rather than treating subjective certainty as reliable evidence of genuine understanding.

Where this fits in the broader cognitive-bias landscape

Overclaiming sits alongside the broader literature on cognitive ability and decision-making biases and the questions about what cognitive tests actually measure. The construct overlaps with related phenomena — Dunning-Kruger meta-cognitive miscalibration, social-desirability response bias, narcissistic self-presentation — without being identical to any of them. Like other dispositional measures of self-knowledge accuracy, it is partially heritable, partially shaped by environmental factors, and partially modifiable through targeted interventions.

The substantive lesson for cognitive-test design and interpretation is that self-reported knowledge or confidence is a problematic measurement target on its own. Performance-based measures and behavioral indicators are less subject to overclaiming; subjective ratings need to be triangulated against direct evidence rather than treated as definitive.

Frequently Asked Questions

What is overclaiming?

Overclaiming is the tendency to claim familiarity with concepts that don’t exist. It is measured by inserting fictitious items into a familiarity-rating task and counting how many fakes a respondent endorses. The pattern is stable across testing occasions and predicts confidence, narcissism, and susceptibility to fake news (Paulhus & Harms, 2004; Pennycook et al., 2020).

Is overclaiming the same as lying?

Not necessarily. Some overclaimers are likely deliberately misrepresenting their knowledge, but others appear to genuinely believe they understand concepts they do not. The empirical evidence suggests overclaiming reflects a mix of impression management, metacognitive miscalibration, and reduced epistemic vigilance, with different individuals showing different patterns.

Does cognitive ability protect against overclaiming?

Modestly. Higher-IQ individuals overclaim somewhat less than lower-IQ individuals, with correlation magnitudes typically 0.20–0.30. The protection is real but incomplete; intelligent people remain susceptible to overclaiming, particularly in domains outside their expertise.

Why do people overclaim more in some cultures than others?

Jerrim, Parker, and Shure (2023) documented substantial cross-national variation in overclaiming using PISA data from nine Anglophone countries. The mechanisms are not fully understood but plausibly involve cultural norms around self-presentation, educational expectations about confidence, and social dynamics that reward apparent competence over calibrated humility.

Can overclaiming be reduced?

Some interventions help. Training in epistemic vigilance — careful evaluation of source credibility, claim plausibility, and one’s own knowledge boundaries — can reduce overclaiming-style errors. Generic “be more careful” appeals are less effective. The most impactful interventions are domain-specific and target the metacognitive skills required to recognize what one doesn’t know.