A huge share of relationship self-help rests on one unstated premise: men and women are wired differently enough that you need a translator to deal with each other. Different communication styles. Different risk appetites. Different needs. The premise is rarely argued for — it’s just there, underneath the chapter titles, doing the work. A new study published in PNAS Nexus in August 2026 takes that premise and runs it through the largest dataset assembled on the question. The gender gaps in core personality traits are real. They’re also shrinking, generation over generation, and the shrinkage tracks when you were born, not how old you currently are.

That second part is the detail that matters. It means this isn’t people mellowing with age into some universal midlife convergence. It’s cultural change, cohort by cohort, and it’s the opposite of what an earlier, influential study predicted would happen as the world modernized.

Quick Verdict

Question	Answer
Who ran the study?	Rainer Kotschy (NBER, Harvard T.H. Chan School of Public Health, CESifo) and Uwe Sunde (LMU Munich, CESifo)
Sample	Roughly 460,000 people across more than 100 countries, combining two survey datasets
Traits measured	Patience, risk-taking, trust, and prosociality
Is the gap gone?	No. It’s smaller in younger cohorts, not eliminated
Age effect or cohort effect?	Cohort. The researchers specifically tested and ruled out that people converge as they individually age
How much smaller?	Gender gaps declined about 21.6% (range 8.6–35.4% across traits) between the 1950 and 1980 birth cohorts
The catch	Self-reported preference measures, and the gap is narrowing faster in less-developed countries than in wealthy ones — the opposite of what a 2018 study predicted

Bottom line: The data doesn’t say men and women are the same. It says the gap between them is a moving target that’s been closing for at least three generations — which makes any self-help advice built on a fixed, essential difference between the sexes harder to defend.

What the Study Actually Tested

Kotschy and Sunde didn’t run a new survey. They combined two existing ones and asked a question neither was originally built to answer directly. The Global Preferences Survey contributes roughly 80,000 respondents across 76 countries, collected in a single wave in 2012. The World Values Survey contributes the bulk of the sample — about 380,000 people across 106 countries and territories, gathered over seven waves between 1981 and 2022. Combined: 460,000 people, over 100 countries, a data-collection window spanning four decades.

That long window is what makes the analysis possible. With one snapshot in time, you can’t tell whether a 25-year-old and a 65-year-old differ because of the years they’ve lived or the era they were born into. With four decades of repeated surveys, you can watch the same birth cohorts get resurveyed at different ages and separate the two. Sunde put it plainly in the study’s write-up on PsyPost: “Disentangling cohort from age effects is notoriously difficult and we have gone a long way to see whether the effects are due to cohort effects or age.” Their answer: it’s cohort. Gender gaps in patience, risk-taking, trust, and prosociality shrink by about 0.01 to 0.02 standard deviations per birth decade, and that decline shows up when you hold age constant and compare people born in different decades — not when you track the same people as they get older.

Are Men and Women Becoming More Alike?

Yes, on four specific measured traits — but the convergence is gradual, uneven across traits, and still leaves a real gap intact. The core numbers, per the study:

1. Patience, risk-taking, trust, and prosociality all show smaller male-female gaps in younger cohorts. Every one of the four traits moved in the same direction. None widened.
2. The average decline is 21.6% over one generation, comparing people born in the 1950s to people born in the 1980s — with the size of the decline ranging from 8.6% to 35.4% depending on which trait you’re looking at.
3. Across the full range in the data, from the 1930s birth cohort to the 1990s birth cohort, gender gaps fell by roughly 0.05 to 0.15 standard deviations — a meaningful shift for preference measures that don’t typically move that much.
4. The gap between men and women born in the 1980s is about 20% smaller than the gap between men and women born in the 1950s. Not closed. Smaller.

That last point is worth sitting with before anyone runs too far with this. A 20% reduction over one generation is a real trend line, not evidence that gender differences in these traits have disappeared or are about to.

The Part That Undercuts a Lot of Relationship Advice

Here’s where this gets uncomfortable for a specific, popular corner of the self-help shelf. Books built on the Men Are From Mars, Women Are From Venus premise — and there’s an entire industry downstream of it, from communication-style guides to “how men and women fight differently” content — treat gendered difference as close to fixed. A biological or deeply essential trait, stable enough to build a permanent translation manual around. Learn his language. Learn her language. The gap is the starting assumption, not something the data has to earn.

Kotschy and Sunde’s finding doesn’t fit that model. If patience, risk tolerance, trust, and prosocial behavior were biologically hardwired sex differences, they shouldn’t be shrinking by cohort. Biology doesn’t reorganize itself every ten years based on what decade someone was born in. Culture does. Socialization does. What children are taught is acceptable, expected, or rewarded by gender does — and that’s exactly the kind of thing that would produce a decline tracking birth cohort instead of age.

This isn’t a new argument in psychology — researchers have debated “nature vs. nurture” framings of sex differences for decades. What’s new is the scale of evidence for the cultural-change side of that argument, specifically on the traits (risk-taking, trust, patience) that gendered communication advice leans on hardest.

None of this means every gendered relationship pattern is fake or that attachment style research is bunk — attachment isn’t the same category of claim as “men are inherently more risk-tolerant.” But it does mean a book that opens with “men and women are fundamentally different” as an unexamined premise is standing on ground that’s been eroding for three generations running.

The Twist: It’s Not Happening Where You’d Expect

The intuitive story would be that gender gaps shrink fastest in wealthy, gender-equal countries — Scandinavia narrows first, poorer and more traditional countries lag. Kotschy and Sunde found close to the opposite. The narrowing is faster in less-developed, less gender-equal countries, and slower — smaller, less statistically significant — in OECD nations that are already relatively gender-equal.

That directly contradicts a well-known 2018 finding. Falk and Hermle’s study in Science, using the same Global Preferences Survey data as one input, found that gender differences in preferences were larger in more developed, more gender-equal countries — the so-called gender-equality paradox, where removing economic constraints seemed to let innate differences express themselves more, not less. That 2018 paper became a go-to citation for the “differences are real and development reveals them” argument. Kotschy and Sunde, using a cohort lens on top of similar underlying data, find the trend running the other way over time: gaps are narrowing everywhere, and narrowing faster in the countries the paradox theory said should show the least movement.

Two respected papers, overlapping data, opposite-sounding headlines. That’s not a reason to throw out either one — it’s a reason to be skeptical of any single study (including this one) being treated as the final word on whether gender differences are “real,” biological, or fixed.

Where This Fits With the “Context Over Universal Claims” Pattern

This site keeps running into research that complicates a tidy, universal self-help premise once someone actually measures it at scale. A Cambridge study found the brain doesn’t age gradually — it reorganizes at four specific ages, which undercuts one-size-fits-all age advice. A decade of panel data found “positive emotion” isn’t a single thing — calm and excitement predict different outcomes. A study of 1,108 people found comparing yourself to your partner splits into two behaviors with opposite effects, not one universally bad habit. The gender personality gap fits the same shape: an assumption treated as fixed and universal turns out to be more specific, more contingent, and more prone to change than the genre built around it assumes.

It also connects to something more concrete on the mental-load side of relationship advice. Drained by Leah Ruppanner and The Balancing Act by Nedra Tawwab both work from the observation that household and emotional labor still split along gender lines in most households — a real, measured pattern, distinct from the trait-level claims in this study. Kotschy and Sunde’s data says the underlying personality traits are converging. It doesn’t say the division of labor already caught up. Those are two different clocks, and conflating them is its own kind of error.

What This Doesn’t Mean

A few things this study does not establish:

• It doesn’t mean gender differences in these traits are gone. A 20% reduction over one generation is a trend, not an endpoint. Gaps in patience, risk-taking, trust, and prosociality still exist in every cohort measured.
• It doesn’t prove the mechanism is socialization specifically, even though that’s the most plausible read. The study identifies a cohort pattern and rules out simple aging — it doesn’t trace the causal chain through classrooms, parenting, media, or policy.
• It doesn’t generalize evenly across countries. The convergence is faster in less-developed, less gender-equal countries and slower — sometimes not statistically significant — in wealthy OECD nations. “Gender gaps are shrinking” isn’t the same claim everywhere on the map.
• It doesn’t measure relationship communication directly. Patience, risk-taking, trust, and prosociality are broad preference measures from economics research, not a study of how couples argue or what they need from each other day to day.
• It doesn’t contradict every finding about gender and development. It contradicts one specific prior claim — the 2018 “gender-equality paradox” result — using a cohort lens the earlier study didn’t have.

What Actually Holds Up, Given This

• Treat “men and women are fundamentally different” as a claim that needs support, not a starting assumption. If a book opens with that premise and never revisits it, that’s worth noticing.
• Communication-style advice can still be useful without the essentialist framing underneath it. “People vary in how directly they express needs” is a defensible claim. “Men and women are wired to communicate differently” is a narrower, harder-to-support version of the same practical advice.
• If you’re picking relationship books, favor ones that treat gendered patterns as documented tendencies with exceptions, not biological law. How to Feel Loved leans on relationship science rather than gendered stereotype, which is the more defensible foundation given where this data is heading.
• Household labor imbalance is a separate, still-real problem from trait-level psychology. Don’t let “the personality gap is shrinking” get used to wave off the mental-load conversation — those are different claims resting on different evidence.

The Bottom Line

Kotschy and Sunde combined two of the largest cross-national preference datasets available — 460,000 people, over 100 countries, four decades of surveys — and found that gender gaps in patience, risk-taking, trust, and prosociality are smaller in younger birth cohorts than older ones, and that the decline tracks who you were born as, not how old you are now. The gap hasn’t closed. It’s been shrinking for three generations, faster in places the leading prior theory said should show the least change. That’s a specific, falsifiable, well-sourced complication for any self-help premise that treats “men and women are fundamentally different” as bedrock instead of a claim with an expiration date.

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Kotschy, R., & Sunde, U., “Gender gaps in patience, risk-taking, trust, and prosociality are smaller among younger cohorts,” PNAS Nexus, Vol. 5, Issue 8, pgag255, August 2026. Additional coverage from PsyPost. Prior finding referenced: Falk, A., & Hermle, J., “Relationship of gender differences in preferences to economic development and gender equality,” Science, 2018. Related reading: Secure Review: Can You Change Attachment Style?, Drained by Leah Ruppanner Review, The Balancing Act by Nedra Tawwab Review, How to Feel Loved Review, and Your Brain Doesn’t Age Gradually. It Resets 4 Times.