A 2010 study by Jouve, drawing on 251 examinees of the Jouve Cerebrals Test of Induction (JCTI), found that males scored higher than females on inductive reasoning at both middle/high-school and college levels, with no reliable interaction between gender and education stage. The mean gender gap was approximately 4.7 raw-score points (Hedges’ g ≈ 0.40) at the school level, where the comparison was statistically marginal (p ≈ .06), and approximately 6.3 points (g ≈ 0.61) at the post-secondary level (p < .01). Education stage produced a substantially larger effect (η²p = 0.114) than gender (η²p = 0.066), and the gender × education interaction was not reliable (η²p = 0.001) — meaning the gender effect was roughly constant across stages, with the apparent “divergence” reflecting differential statistical power across cell sizes rather than a substantive interaction (Cogn-IQ, 2025).
This article situates that single-study finding within the broader meta-analytic literature on sex differences in inductive reasoning, fluid intelligence, and the variability of cognitive test scores — where the central pattern is that average sex differences are small while distributional differences (greater male variance, more males at upper and lower extremes) are well-documented and have specific implications for samples drawn from selective educational settings.
What the JCTI measures
The JCTI is a computerized adaptive test of inductive reasoning developed in 2002 with continuing revision. It uses nonverbal figurative items, a 2-parameter logistic IRT model, expected a posteriori (EAP) ability estimation, and maximum-information item selection. Typical administration is 19–42 items (mean ≈ 30) drawn adaptively from a calibrated bank, with marginal reliability ρ ≈ 0.91 across an N = 1,003 operational sample. Output is the Inductive Reasoning Index (IRI; M = 100, SD = 15) on the standard IQ metric (Cogn-IQ, 2025).
The construct measured is fluid intelligence (Gf) within the Cattell-Horn-Carroll (CHC) framework — specifically, inductive reasoning (I): the ability to identify abstract patterns and rules from observed instances and apply them to novel cases. Inductive reasoning is among the most heavily g-loaded cognitive abilities, and nonverbal inductive-reasoning measures (such as Raven’s Progressive Matrices and the JCTI) are widely used as relatively language-independent indicators of general cognitive ability.
The Jouve 2010 study in detail
The original cross-sectional study analyzed JCTI fixed-form scores from 251 examinees stratified by gender (Female, Male) and education (Middle/High School, Post-secondary = College/University). Cell sizes and means (raw scores) were:
- Middle/High School – Female: n = 37, M = 21.68, SD = 12.34
- Middle/High School – Male: n = 66, M = 26.39, SD = 11.53
- Post-secondary – Female: n = 42, M = 28.10, SD = 10.76
- Post-secondary – Male: n = 106, M = 34.40, SD = 10.11
Within-stratum gender contrasts:
- Middle/High School: Male − Female = +4.72; Welch t ≈ 1.91, df ≈ 71, p ≈ .06; 95% CI [−0.22, 9.65]; Hedges’ g ≈ 0.40 (small-to-medium).
- Post-secondary: Male − Female = +6.30; Welch t ≈ 3.27, df ≈ 71, p ≈ .002; 95% CI [2.46, 10.15]; Hedges’ g ≈ 0.61 (medium).
Within-stratum education contrasts:
- Females: Post-secondary − M/HS = +6.42; Welch t ≈ 2.45, p ≈ .016.
- Males: Post-secondary − M/HS = +8.00; Welch t ≈ 4.64, p < .001.
The omnibus two-way ANOVA produced:
- Education main effect: F(1, 247) = 31.7, p < .001, η²p = 0.114.
- Gender main effect: F(1, 247) = 17.6, p < .001, η²p = 0.066.
- Gender × Education interaction: F(1, 247) = 0.28, p = .60, η²p = 0.001.
The interaction term is the analytically diagnostic result. A reliable interaction would mean the gender effect changes with education stage — the pattern that “divergence emerges in higher education” implies. The data show no such interaction: the gender effect is approximately the same magnitude across stages (g ≈ 0.40 in M/HS and g ≈ 0.61 in post-secondary, which differ by less than the expected sampling noise at these cell sizes). The within-cell p-value difference between the two stages (.06 vs. .002) reflects sample size, not a different effect size.
Two interpretive caveats accompany the original report:
- The design is cross-sectional. Education strata also differ in age distribution, so part of the education main effect reflects developmental differences rather than education per se.
- Cell sizes are unequal, with the post-secondary male cell roughly three times the size of the M/HS female cell. Welch tests addressed the variance heterogeneity, but power asymmetry across cells affects within-cell p-values and contributes to the appearance of a stage-specific effect.
Sex differences in inductive reasoning: the meta-analytic picture
The single-study finding from Jouve (2010) becomes more interpretable in the context of the broader literature. Two recent meta-analyses provide the relevant anchor.
Waschl and Burns (2020) synthesized 98 studies (combined N = 96,957 adults) on sex differences across 40 distinct types of inductive-reasoning tests. The pooled summary effect was g = +0.13 in favor of males — a small effect, with substantial variation across study (range −0.54 to +0.68) and meaningful moderation by stimulus and item type. The pooled effect is well below the magnitude reported in the JCTI college sample (g ≈ 0.61) and closer to the magnitude in the school sample (g ≈ 0.40). The variance across the 98 studies is consistent with the JCTI sample being one realization of a distribution where the population effect is small and individual studies vary substantially around it.
Giofrè, Allen, Toffalini, and Caviola (2022), in a meta-analysis of 79 WISC-battery studies (N = 46,605 school-aged children), reported that fluid intelligence showed minimal gender differences. Males held small advantages on visual and crystallized measures and females held a small advantage on processing speed. Earlier WISC editions showed more pronounced gender differences than recent editions, suggesting some of the historical sex-difference reports reflect test-specific item construction rather than substantive cognitive differences. The fluid-intelligence finding aligns with the Waschl-Burns small-positive-effect picture in adult samples.
The general claim — Hyde’s (2005) gender similarities hypothesis — is that on most cognitive abilities, mean sex differences are small (Cohen’s d < 0.35) and that emphasizing them obscures the substantial overlap of the male and female distributions. Hyde’s analysis of meta-analyses across cognitive, communication, social-personality, and motor domains found 78% of effect sizes in the small or near-zero range. For inductive reasoning specifically, the Waschl-Burns g = +0.13 falls within this range.
The variance and high-scoring-individuals finding
The single most influential paper on the structural form of cognitive sex differences is Hedges and Nowell (1995), who analyzed mental-test scores from six U.S. national probability samples. Their headline finding was not about means but about variance: across nearly all cognitive abilities, the male distribution had larger variance than the female distribution, with male/female variance ratios typically between 1.05 and 1.25. The mean differences were small in either direction depending on the measure; the variance differences were consistent and replicable.
The variance pattern has a specific consequence for samples drawn from selective educational settings. If two distributions have approximately equal means but one has greater variance, the proportion of individuals at high cutpoints differs systematically: at +2 SD relative to the combined mean, the higher-variance group is over-represented. Hedges and Nowell quantified this for several abilities and showed that males consistently outnumbered females among the highest-scoring 5–10% on most cognitive tests, even when mean differences were near zero.
This matters for interpreting the Jouve 2010 JCTI study. Post-secondary samples are not random samples of the general population — they are selected on academic performance and admission criteria that correlate with cognitive ability. If the male and female JCTI distributions in the general population have a small mean difference (g ≈ 0.13 per Waschl-Burns) and a larger male variance (per Hedges-Nowell), then a college-selected sample will show a larger apparent male-female mean difference than the underlying population, simply because selection differentially samples the upper tails of the two distributions.
The JCTI college finding (g ≈ 0.61) is consistent with this selection-effect interpretation: the underlying population effect is closer to the M/HS finding (g ≈ 0.40) and to the meta-analytic estimate, but the post-secondary sample compounds this with the upper-tail selection that the Hedges-Nowell variance pattern predicts.
What the data do and do not support
Taking the Jouve 2010 study and the broader literature together:
- Average sex differences in inductive reasoning are small. The meta-analytic estimate is g ≈ +0.13, well within the gender-similarities range. Most of the male and female distributions overlap substantially.
- The Jouve 2010 within-cell effect sizes (g ≈ 0.40 to 0.61) are larger than the meta-analytic estimate but consistent with sampling variability and possible upper-tail selection in post-secondary samples.
- The “divergence at higher education” claim is not supported by the JCTI data at the level of a Gender × Education interaction. The omnibus interaction was not reliable (p = .60, η²p = 0.001). Reports framed around stage-specific divergence overstate what the analysis shows.
- Distributional differences are well-documented and matter for selected samples. Hedges and Nowell’s variance findings explain why high-selection settings (top universities, gifted-and-talented programs) can produce mean gender differences that exceed the underlying population effect.
- Cohort and test-edition effects matter. Giofrè et al. (2022) found that earlier WISC editions show larger sex differences than recent editions, suggesting item-construction and test-development practices contribute to historical sex-difference reports independent of any cognitive substrate.
Practical implications for educators and researchers
For educators interpreting cognitive-test data on classroom or school populations:
- Expected mean gender differences in inductive reasoning are small. Programs that report large gender gaps on a particular cognitive measure should consider whether the measure has known sex-difference patterns, whether the sample is selected (gifted programs, advanced classes), and whether item content might favor one group on construct-irrelevant dimensions.
- Variance differences imply tail-effects. If male and female distributions have similar means but male distributions have larger variance, the highest-scoring and lowest-scoring tails will both be male-skewed. Educational identification practices that focus on upper tails will identify more males; remediation practices that focus on lower tails will identify more males. Both patterns flow from the same variance asymmetry.
- Selection compounds underlying differences. Cognitive-test data drawn from already-selected groups (college admits, scholarship recipients) will show larger gender differences than underlying-population samples. This is mechanical, not informative about pedagogical effects.
For researchers designing or interpreting sex-difference studies on cognitive abilities:
- Report Cohen’s d or Hedges’ g with confidence intervals alongside p-values; effect sizes are interpretable across studies in a way that significance tests are not.
- Test interaction terms explicitly when the substantive question is whether a gender effect varies across some moderator; do not infer interactions from differences in within-stratum p-values, which conflate effect-size differences with sample-size differences.
- Report variance ratios alongside means; the Hedges-Nowell pattern remains under-reported in primary studies despite its centrality to the structural picture.
- Account for sample selection. If the sample is drawn from a selected population, the underlying-population effect will differ from the observed effect in calculable ways.
The takeaway
The Jouve (2010) JCTI study found a male advantage in inductive reasoning at both middle/high-school and post-secondary stages, with no reliable Gender × Education interaction. The within-cell effect sizes (Hedges’ g ≈ 0.40 to 0.61) are larger than the meta-analytic estimate from Waschl and Burns (2020) (g ≈ +0.13 across 98 studies and ~97,000 adults), consistent with sampling variability and likely upper-tail selection in the post-secondary sample. The broader literature — Hyde’s (2005) gender similarities hypothesis, Hedges and Nowell’s (1995) variance-asymmetry findings, and Giofrè et al.’s (2022) WISC meta-analysis — supports a structural picture of small mean differences in fluid reasoning combined with greater male variance that has implications for selected samples. Single-study findings on sex × education effects should be interpreted within this distributional framework rather than treated as evidence of stage-specific cognitive divergence.
Frequently asked questions
Are there sex differences in inductive reasoning?
The meta-analytic estimate from Waschl and Burns (2020), pooling 98 studies and N = 96,957 adults, was Hedges’ g = +0.13 in favor of males—a small effect with substantial variation across studies (range −0.54 to +0.68). Most of the male and female distributions overlap substantially, consistent with Hyde’s (2005) gender similarities hypothesis: average sex differences on most cognitive abilities are small (Cohen’s d < 0.35).
What did the Jouve (2010) JCTI study find?
In a sample of 251 examinees, males scored higher than females at both middle/high school (g ≈ 0.40, p ≈ .06) and post-secondary stages (g ≈ 0.61, p ≈ .002). The omnibus ANOVA showed reliable gender (η²p = 0.066) and education (η²p = 0.114) main effects but no reliable Gender × Education interaction (F = 0.28, p = .60, η²p = 0.001). The gender effect was approximately constant across education stages.
Do gender differences in cognition diverge in higher education?
The JCTI data do not support that claim. The Gender × Education interaction was not statistically reliable. The apparent within-cell p-value difference between school (.06) and college (.002) reflects sample-size differences, not different effect sizes. Selection effects in post-secondary samples can also amplify apparent gender gaps relative to the underlying population effect.
What did Hedges and Nowell (1995) find about cognitive variance?
Across nearly all cognitive abilities in six U.S. national probability samples, the male distribution had larger variance than the female distribution (variance ratios typically 1.05–1.25). Mean differences were small in either direction; variance differences were consistent and replicable. Larger male variance implies that males are over-represented at both upper and lower tails of cognitive distributions even when means are similar.
Why might selected samples show larger gender gaps?
Selection mechanically amplifies tail differences. If the underlying male and female distributions have a small mean difference and a larger male variance, then a college- or gifted-selected sample drawn from the upper tail will show a larger apparent male-female mean difference than the general-population effect. This is mechanical, not informative about pedagogical effects.
How should sex-difference findings be reported?
Report Cohen’s d or Hedges’ g with confidence intervals alongside p-values. Test interaction terms explicitly when the substantive question is whether an effect varies across a moderator—do not infer interactions from differences in within-stratum p-values. Report variance ratios alongside means, since the Hedges-Nowell pattern remains under-reported despite its centrality. Account for sample selection in interpretation.
References
- Cogn-IQ. (2025). JCTI Technical Manual. Cogn-IQ. https://www.cogn-iq.org/methods/jcti-manual/
- Jouve, X. (2010). Interactive effects of educational level and gender on Jouve Cerebrals Test of Induction scores: A comparative study. Cogn-IQ Research Papers. https://pubscience.org/ps-1mkXB-3ee281-8soZ
- Hyde, J. S. (2005). The gender similarities hypothesis. American Psychologist, 60(6), 581–592. https://doi.org/10.1037/0003-066X.60.6.581
- Hedges, L. V., & Nowell, A. (1995). Sex differences in mental test scores, variability, and numbers of high-scoring individuals. Science, 269(5220), 41–45. https://doi.org/10.1126/science.7604277
- Waschl, N., & Burns, N. R. (2020). Sex differences in inductive reasoning: A research synthesis using meta-analytic techniques. Personality and Individual Differences, 164, 109959. https://doi.org/10.1016/j.paid.2020.109959
- Giofrè, D., Allen, K., Toffalini, E., & Caviola, S. (2022). The impasse on gender differences in intelligence: A meta-analysis on WISC batteries. Educational Psychology Review, 34(4), 2543–2568. https://doi.org/10.1007/s10648-022-09705-1
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Parity During Early Education: The study found no significant differences in cognitive performance between genders during middle and high school. This suggests that educational experiences at these levels may not contribute to performance disparities in inductive reasoning. Divergence in Higher Education: At the collegiate level, male participants demonstrated stronger performance compared
Sharma, P. (2010, January 27). Gender, Education, and Cognitive Outcomes. PsychoLogic. https://www.psychologic.online/gender-education-cognitive-outcomes/

