The episode opens with Chris selling limited-edition Modern Wisdom merch, then immediately pivots to a Northumbria University study that used motion-capture technology on 30 male dancers and turned their movements into avatars for women to rate. The result: men who moved their head, neck, and torso with creative rhythm variation were rated most attractive. Macken Murphy notes the dance looks like 'dad dancing', but adds a fascinating wrinkle — just as facial attractiveness research sometimes finds femininity preferred over pure masculinity, dancing seems to follow the same pattern. A brief, entertaining riff on shadowboxing and football chants as the ultimate icks sets the tone for a wide-ranging, data-driven conversation.

Rob Henderson opens a fascinating case study around the looksmaxing influencer Clavicular, who reportedly became sterile after self-injection experiments and told The New York Times it was worth it. Henderson argues that women's attraction to Clavicular likely comes from his fame, not his looks — and that average men replicating his protocol would trigger perceptions of vanity and narcissism. Macken Murphy reveals that looksmax.org's first rule used to be 'don't talk about looksmaxing', reflecting an evolved intuition that cosmetic effort, once detected, devalues the signal. A Chinese study by Xia and colleagues supports this: plastic surgery boosted attractiveness ratings but attenuated dateability when men knew about it. The panel wrestles with whether this is cheater detection, personality inference, or simply that attraction evolved to respond to health signals rather than the underlying health itself.

A moment of genuine excitement breaks out when Steve Stewart-Williams reveals his PhD student Louisa Lee is doing the first systematic empirical work on the ick — research that barely existed when she began, and has since been scooped once. The ick is framed not as a social quirk but as a product of evolved disgust: women, being choosier on average, have a stronger visceral selection mechanism that fires when a partner reveals social incompetence or health-relevant cues. Macken Murphy explains the asymmetric logic: men risk missing mating opportunities by being too choosy, while women risk catastrophic mating errors by not being choosy enough. Chris Williamson cites Diana Fleischman's self-reported attraction dips when her husband misses a driving turn or lands a joke badly — a modern analogue of an ancient calibration system.

Rob Henderson traces the Chad myth to two sources: dating app swipe data (where the top 10% of men on Hinge get 60% of likes) and social media virality that amplifies anomalous rejection stories. But digging into actual behavioural data reveals near-symmetry: roughly 18-20% of men and 12-18% of women report 3 or more partners in the past year, and this has not changed since at least 2000. The most common answer to 'how many partners in the past year' is one, followed by zero. Steve Stewart-Williams reinforces the point with the concept of the 'sociosexual few': the promiscuous men are mostly sleeping with the equally promiscuous women, not the general female population. The real harm of the myth, Henderson argues, is that incel men see the visible promiscuous women online and mistakenly assume that's all women — missing the 'dark matter' of women who simply aren't posting.

Building on the Chad discussion, the panel turns to what Rob Henderson calls 'sexual communism': the idea that monogamous marriage was essentially DEI for average men, pairing them one-to-one with women in a market where free competition would favour the top minority. Researchers Teng and Qi are cited using terms like 'sexual socialism' and 'sexual redistribution'. Henderson notes that today's cultural moment sees the manosphere on the right calling for a return to strict norms, while progressive women independently reinvent similar constraints under labels like 'demisexual' or 'solopoly'. Chris Williamson raises a puzzle: why would women push back against reinstating monogamy norms if those norms historically benefited women by guaranteeing male investment? Steve Stewart-Williams counters that women generally prefer having one man to themselves. Macken Murphy adds a nuance: in strongly polygynous systems, some women might rationally choose to be the second wife of a high-status man rather than the only wife of a low-status one.

Rob Henderson raises ethnographic evidence of serial monogamy among hunter-gatherers — pair-bonding, having children, then reforming new bonds as romantic feelings dissipate. Steve Stewart-Williams confirms this is common and adds that even in those societies, a non-trivial ~5% of first marriages last for life. Chris Williamson turns to a real-time ChatGPT query: a 2026 Kinsey Institute study of 10,000+ US adults finds the average passionate love count is 2.05 times across a lifespan, with 30% experiencing it twice and 11% four or more times. The implication: without reliable contraception, nearly everyone would have cycled through multiple partners who became parents. The data broadly supports a serial monogamy model, with a small but real tail of highly polygynous individuals — and a mass of ordinary people who fall in love twice and call it a life.

Macken Murphy walks through a 37-year debate between evolutionary psychologists and social role theorists over whether sex differences in mate preferences are innate or economically determined. His PNAS experiment, which placed participants in 45 different virtual economic environments, found that when women (or men) are economically disadvantaged or in conditions of gender inequality, they upregulate preferences for resourceful partners. Critically, beauty preferences didn't budge in any condition. Murphy explains this as strategic preference adjustment — not necessarily a domain-specific evolved module, but a rational reweighting of priorities given the incentive landscape. The age preference puzzle is also raised: why didn't age preferences shift? Chris Williamson proposes — correctly, it turns out — that age is a strong proxy for wealth, so controlling for wealth removes the age signal. Murphy confirms this is exactly what they wrote in the paper.

Building on the PNAS study, the group examines a well-replicated finding: men primed with scarcity — through hunger, economic hardship, or famine conditions — shift toward preferring heavier women. Macken Murphy frames fat as a caloric bank account and fertility signal: in a famine, a heavier woman can definitely get pregnant while a starving one cannot. Steve Stewart-Williams pushes back, questioning why preferences switch so rapidly with something as minor as being hungry leaving a dining hall. Murphy clarifies these within-person shifts are small (about 10 pounds of preference shift); it's the cross-cultural differences that are dramatic, with some cultures — Jamaica, South Africa's Zulu, St Kitts — finding BMIs in the 30s beautiful. The panel discusses the 'fattening hut' custom in Mauritania, where women before marriage restrict movement and increase caloric intake as a beautification practice, and men reportedly spied on these women as a coveted spectacle. Rob Henderson floats an elegant theory: in any environment, the rarer body type signals conscientiousness — thinness in abundance signals impulse control; heaviness in scarcity signals industriousness.

Chris Williamson cites Vincent Harinam's research showing high-powered career women have an increased — not decreased — preference for high-powered men. Macken Murphy explains the distinction between absolute and relative preferences: rich women want richer men absolutely, but as a relative ranking among all their preferences, resources may decline. The group agrees the cleanest explanation is simply that high-standard people apply high standards everywhere — the same perfectionism that drove their career drives their mate selection. Murphy adds that the Institute for Family Studies data shows the top quintile of women is already slightly dating down economically, but Steve Stewart-Williams reframes this as the 'tall girl problem': there simply aren't enough ultra-high-earning men, so settling is supply-constrained, not preference-driven.

Macken Murphy tees up Paul Eastwick's influential challenge: when you measure mate preferences through speed dating or by seeing how stated preferences predict actual partner evaluation, the sex differences largely disappear — women care more about looks than they admit, men more about resources, with the net being near equality. Steve Stewart-Williams responds carefully: Eastwick's speed dating samples are heavily university-skewed, with little variance in career prospects; speed dating contexts amplify looks precisely because you learn so little about someone in minutes; and survivor bias means the couples whose relationships dissolved because the man was unemployed have already left the sample. The worldwide preference-matching study is also cited as a powerful counter-argument, showing that actual partner choices globally track evolutionary predictions.

The conversation sharpens around two provocative claims: first, Jake Kozlowski's Keeper AI data showing women are 12 times more likely than men to refuse a partner who earns less (6x for intelligence, 4x for education), collected in a high-stakes environment where men pay $50,000 for the service; second, a late-2010s study finding college students actively using Tinder scored 0.3-0.4 standard deviations higher on dark triad traits. Chris Williamson connects the dots: the characteristics that make someone a winning dating app user — confident self-presentation, emotional detachment, novelty-seeking — may be precisely the traits that make them a bad spouse. Macken Murphy notes that Keeper AI's preferences occupy a hybrid space between stated and revealed preferences: you're telling a matchmaker with real financial skin in the game what you want.

Chris Williamson cites a Whitmer study in which a gamified dating app without height filters found facial attractiveness to be 12 times more influential than height on user swiping. Macken Murphy, who tweeted the finding, pre-empts the obvious objection — 'it's a photo competition app, so of course photos matter' — by noting the study specifically controlled for this with a sophisticated design that impressed even prominent challenging scholars. The lack of a height filter is crucial: in real apps, height influences behaviour partly through filter exclusion, not pure visual assessment. Rob Henderson raises whether the preference for 6 feet specifically is partly arbitrary — pointing out that in Europe, 180cm (5'10.5") serves the same cultural function as a round number threshold. The segment closes with the group joking about 'metric maxing' as the new height hack.

Macken Murphy zooms out from the looksmaxing moment to place it within a documented century-long trend. Historian Lynn Luciano's work shows male beautification rising decade-by-decade since the 1990s. Marta Cowell's cross-cultural beautification study found women beautify more in all but seven countries, with the male exception being weightlifting. Murphy's data analysis shows weightlifting has gone from a non-behaviour to something essentially every young man does recreationally across generations. The deeper argument: as women's financial emancipation reduced the signal value of resource provisioning, men shifted competitive effort toward physical presentation and — crucially — parenting. A man today spends more time with children than mothers did in the 1950s. Rob Henderson adds that among college-educated men, paternal involvement has skyrocketed; among non-college men, it has barely changed. Steve Stewart-Williams offers the evolutionary note: women do find muscularity and good grooming attractive, but is less convinced women's luxury handbag spending signals resources to attract men — more likely it's intra-female intimidation.

The panel turns to one of the most striking studies in evolutionary psychology. In Puts' design, one group of men rated short video clips of other men on fighting formidability; a separate group of women rated those same men on sexual attractiveness. The men in the videos were then followed up 18 months later for partner count. The result: formidability, as judged by other men, predicted partner count. Women's attractiveness ratings had zero predictive power. Chris Williamson draws the pointed conclusion that looksmaxers may have accidentally optimised for the right variable — if their hypermasculine appearance signals formidability to other men rather than attractiveness to women, the mating benefits flow through male-to-male status dynamics, not the female gaze.

Rob Henderson builds on Louise Perry's Spectator piece about OnlyFans as a supernormal stimulus for women (thousands of men praising you simultaneously), applying the same logic to female teacher scandals. When an attractive 25-year-old woman undresses before an experienced 28-year-old man, the response is pleasant but muted. When she does so before a 16-year-old encountering a mature woman for the first time, the intensity of his reaction — that specific look — is something no adult male encounter can replicate. Henderson is careful to note male teachers still commit these transgressions far more frequently; female scandals go viral precisely because they're anomalous. Chris Williamson connects this to his own reading of Freida McFadden's thriller 'The Teacher', whose twist forces the reader to confront their asymmetric moral reactions to the same act committed by different genders.

Rob Henderson describes a forced-choice Twitter poll contrasting sleeping with someone you find intensely attractive who is unattracted to you versus someone you find unattractive who finds you intensely attractive. Men chose attractiveness (75%); women chose being desired (75%) — an almost perfect inversion that Henderson quips makes it look like men and women were made for each other. Chris Williamson connects this to a regretted moment in his Esther Perel interview where she implied women need wooing and he should have pushed back: being desired may be the single most powerful female turn-on. The segment is lighthearted, with a long detour identifying who Rob Henderson looks like (eventually settled on Short Round from Indiana Jones).

Steve Stewart-Williams lays out two complementary dangers: overstating sex differences historically forced people into rigid gender roles, while minimising them creates mirror-image harms. The medical example is sobering — women's heart attack symptoms (primarily shortness of breath) are far less known than men's (chest pain radiating down the arms), and this knowledge gap cost lives. Rob Henderson adds a safety angle: a young woman who genuinely believes men and women are psychologically identical may dangerously underestimate the risk posed by sexually predatory men at the extreme tail of the aggression distribution, even if average sex differences in aggression are modest. The panel lands on a nuanced position: acknowledge the differences regardless of their origin, understand where they come from, and be wary of both the ideological pressures to overstate and understate them.

Chris Williamson asks for an update on the dual mating and mate-switching hypothesis, a contested area of evolutionary psychology. Macken Murphy acknowledges he has behind-the-scenes access to promising preliminary findings from Ryan Dobson's group but refuses to share them, citing academic norms around pre-publication conference work. The exchange is good-humoured — Chris likens it to Navy SEALs who know classified details but can't speak on air — and Steve Stewart-Williams notes that conference presentations are generally considered public, creating a brief amusing debate about academic etiquette.

All four participants admit genuine uncertainty about one of the most puzzling sex differences in relationship psychology. Women's sexual desire declines precipitously within the first year of a relationship — dropping roughly by half — and continues falling even as men's stays relatively flat. Rob Henderson floats the obvious adaptive story: women at peak fertility have the strongest desire. Macken Murphy complicates it: if they remarry, desire goes back up, suggesting it's not simply fertility decline but relationship-specific. Murphy's proposed mechanism: early high desire is a mate-retention strategy ('get them on the hook'), which then transitions into a bargaining resource once commitment is secured. Rob Henderson cites Roy Baumeister's research showing men report wanting about twice as much sex as they're getting in relationships, while women report having roughly the amount they want — suggesting couples converge on the woman's preferred frequency.

Rob Henderson opens a deep methodological question: what counts as the baseline for human nature? Hunter-gatherers in relative scarcity, shaped by the EEA? Or modern rich societies where, now that survival needs are met, 'true' traits can finally express themselves? Steve Stewart-Williams suggests both approaches are informative — consistency across very different societies is strong evidence of innate nudges — and adds that abundant societies may allow traits to express to a degree beyond what selection actually produced. Macken Murphy raises the sharpest challenge: sex differences in mate preferences are actually less consistently found among extant hunter-gatherers than in industrialised populations. He cites anthropologist William Buckner's critique that if these preferences evolved in a hunter-gatherer EEA, you'd expect them to be most visible there. The Wodabe of the Sahel are offered as a reversal case — men wearing heavy makeup competing in male beauty pageants judged by women. Steve Stewart-Williams acknowledges this gives him genuine pause but notes that cross-cultural folktale data consistently shows men's resources and women's appearance valued asymmetrically across world regions.

Rob Henderson raises an underexplored natural experiment: if sex differences in mate preferences are evolutionary rather than socially constructed, gay men should show heightened emphasis on physical appearance (they do, empirically), and gay women should show heightened emphasis on resources and status in female partners. Steve Stewart-Williams tentatively confirms this is the case, adding that gay women don't prioritise physical appearance in female partners the way gay men do — consistent with the evolved pattern. Chris Williamson floats a sex toy study idea: the fact that dildos resemble a male anatomy despite no intrinsic reason they need to might itself be revealing data. The episode closes warmly, with Rob Henderson plugging his Substack and paperback memoir 'Troubled', Steve Stewart-Williams plugging 'A Billion Years of Sex Differences' and the Nature Nurture Nietzsche Newsletter, and Macken Murphy — mortified — having his childhood 'Hamster Man' nickname and T-shirt revealed to the world.

Rob Henderson raises an underexplored natural experiment: if sex differences in mate preferences are evolutionary rather than socially constructed, gay men should show heightened emphasis on physical appearance (they do, empirically), and gay women should show heightened emphasis on resources and status in female partners. Steve Stewart-Williams tentatively confirms this is the case, adding that gay women don't prioritise physical appearance in female partners the way gay men do — consistent with the evolved pattern. Chris Williamson floats a sex toy study idea: the fact that dildos resemble a male anatomy despite no intrinsic reason they need to might itself be revealing data. The episode closes warmly, with Rob Henderson plugging his Substack and paperback memoir 'Troubled', Steve Stewart-Williams plugging 'A Billion Years of Sex Differences' and the Nature Nurture Nietzsche Newsletter, and Macken Murphy — mortified — having his childhood 'Hamster Man' nickname and T-shirt revealed to the world.