Modern Wisdom"Women Are Furious About This Research." - Darby Saxbe
CHAPTERS
- 0:00 – 2:19
Dad brain: measurable cortical remodeling tied to hands-on caregiving
Darby Saxbe explains her lab’s longitudinal brain-scan work showing first-time fathers lose about ~1% gray matter volume during the transition to parenthood—similar in direction to “mom brain,” but smaller and more variable. The biggest changes appear in dads who feel bonded before birth and spend more time caregiving after birth, suggesting experience-dependent brain tuning rather than a purely biological switch.
- •Fathers show gray matter volume reduction across early parenthood; not framed as “bad,” likely pruning/efficiency
- •Dad changes are mostly cortical; mothers show broader whole-brain (including subcortical/hormone-linked) changes
- •Magnitude differs: ~1% in dads vs ~2.5% in moms
- •Dad brain change correlates with time off, daily caregiving time, and bonding/pleasure with baby
- 2:19 – 3:15
How fatherhood norms shifted: from 1950s provider model to hands-on millennial/Gen Z dads
The conversation situates dad brain in a historical shift: fathers’ daily parenting time has dramatically increased over recent decades. The pandemic is described as an inflection point that accelerated hands-on involvement, and the data suggest the increase has persisted into the present.
- •Dads’ daily parenting time has tripled/quadrupled since mid-20th century norms
- •COVID-era remote work increased exposure to day-to-day parenting and that change persisted
- •Millennial dads spend more time with kids than prior cohorts; Gen Z may exceed that
- •Changing expectations create new pressures and new opportunities for fathers
- 3:15 – 7:12
Cross-cultural fatherhood: Aka cooperative caregiving vs Kepsigis prohibitions on infant handling
Saxbe contrasts two African societies to show father involvement is highly culturally contingent. In egalitarian, cooperative economies (Aka), fathers stay close and help with infants; in more hazardous, specialized economies (Kepsigis), men avoid infant handling early on and focus on provisioning and later-child mentoring.
- •Aka fathers: high proximity to infants; cooperative resource gathering supports shared roles
- •Kepsigis fathers: cultural prohibitions against picking up babies in the first year; masculinity beliefs shape norms
- •Economic ecology (risk, labor demands) drives role specialization vs flexibility
- •Modern societies may resemble cooperative models more as women’s labor participation rises
- 7:12 – 9:11
What changes during pregnancy for dads: hormones, worry, sleep disruption—and limits of the data
Chris probes why scans begin mid-pregnancy and whether earlier baselines matter. Saxbe outlines what’s known about expectant fathers—hormonal shifts, emotional changes, relationship stress, and early sleep disruption—while emphasizing uncertainty about the exact time course of paternal brain remodeling.
- •Ideal study design would include preconception baselines; funding/logistics often prevent it
- •Evidence in mothers shows pregnancy itself changes the brain; dads may change mostly post-birth
- •Expectant fathers show hormone changes, new worries, relationship shifts, and early sleep disruption
- •Hypothesis: parenting experience and social/cognitive demands are key drivers of paternal remodeling
- 9:11 – 13:47
Fathers in the delivery room: history, benefits, risks, and conflict’s impact on birth outcomes
They discuss the relatively recent norm of dads attending births and how human childbirth has long depended on helpers (historically women kin/midwives). Saxbe shares her lab’s findings that negative conflict styles during pregnancy predict more medically complex births and more stressful appraisals by both partners, underscoring childbirth as a social and physiological process.
- •Human birth is unusually difficult; social support historically helped mothers deliver safely
- •Dads’ delivery-room presence rose mainly in the 1960s–70s after medicalization trends
- •Continuous support can improve birth experiences; unprepared/terrified dads may add stress
- •Lab finding: hostile/negative couple conflict in pregnancy predicts riskier, more stressful births
- 13:47 – 15:17
Sympathetic pregnancy (couvade): controversial evidence and why it irritates moms
Chris asks whether ‘male pregnancy’ symptoms are real. Saxbe treats couvade as more anecdotal than well-established, noting her lab didn’t find hormone–symptom links, and suggests many reported symptoms resemble stress responses. They also address why this research can provoke backlash from women.
- •Couvade describes expectant dads reporting nausea, weight gain, or labor-like pains
- •Evidence base is limited; Saxbe’s sample found no strong hormone associations
- •Many symptoms overlap with stress/anxiety (GI distress, sleep problems)
- •Cultural ‘contagion’ and empathy may amplify shared experiences—while still not equating pregnancies
- 15:17 – 17:54
What couples should prioritize during pregnancy: communication, realistic birth education, and expectations
Saxbe encourages couples to build communication and conflict skills and to include fathers in birth education. She argues that relying on pop-culture portrayals and expecting a baby to “fix” a relationship sets couples up for disappointment, given the reliable post-birth drop in relationship satisfaction.
- •Learn to communicate, listen, and manage conflict before the baby arrives
- •Include dads in birth education to normalize labor stages and supportive behaviors
- •Pop culture often misrepresents birth; realistic preparation reduces fear and stress
- •A baby reliably strains relationships; don’t treat parenthood as a relationship repair strategy
- 17:54 – 24:18
The real cause of dad brain: practice-driven caregiving and ‘turning up the dial’
After an ad break, the conversation returns to the core mechanism: dads’ neural and hormonal changes track caregiving, not mere fatherhood status. Saxbe frames fathers as ‘facultatively’ adaptable—able to become sensitive caregivers when needed—shaped by culture, relationship stability, and practical demands.
- •Dad brain requires hands-on caregiving repetition—like learning any complex skill
- •Moms have a higher baseline ‘investment floor’ due to pregnancy’s energetic demands
- •Fathers’ caregiving is more context-sensitive (culture, partner availability, family needs)
- •Human pair-bonding and paternity uncertainty can influence paternal investment strategies
- 24:18 – 27:59
How to trigger dad brain: specific caregiving behaviors and what the brain is optimizing
Chris asks for a ‘routine’ that maximizes dad brain changes. Saxbe lists high-contact, high-responsibility infant care (carrying, diapering, feeding, bathing, co-sleeping) and explains that remodeling appears strongly in the mentalizing/empathy network, with tradeoffs in working memory for non-baby tasks but gains in baby-salient memory.
- •High-impact behaviors: holding, diapering, feeding, bathing, and close sleep proximity
- •Neural targets include the mentalizing network (reading emotions/intentions; empathy)
- •Gray matter reduction likely reflects pruning and efficiency rather than ‘damage’
- •Working memory for non-salient objects may dip; baby-relevant memory and sensitivity can improve
- 27:59 – 33:48
Long-term effects: parenting skills transfer, social integration, and ‘younger-looking’ brains with kids
They explore evidence that parenthood may be neuroprotective in later life, with UK Biobank findings that having children (up to ~3) correlates with better cognitive aging markers in both sexes. Saxbe hypothesizes social integration as a plausible mechanism, and they discuss how caregiving skills can generalize to leadership, teaching, and other prosocial roles.
- •UK Biobank data: parents’ brains can appear ‘younger’ via ML-based brain-age metrics (up to ~3 kids)
- •Effect in dads suggests mechanisms beyond pregnancy/breastfeeding; likely social integration
- •Short-term salience narrowing can later yield stronger skills and networks
- •Caregiving can be reframed as a broader, even traditionally masculine, prosocial role
- 33:48 – 38:50
Deadbeat dad narrative and bonding windows: involvement is not binary and attachment can form later
Saxbe challenges simplistic ‘present vs absent’ father framing, describing gradations like non-residential but engaged dads and personal examples of transformation through custody shifts. They also discuss whether bonding has a critical window; Saxbe argues bonding can occur across childhood, including in adoption/stepfamilies, if adults invest consistent time and effort.
- •Father presence in the US shows a U-shaped trend: decline then rebound in recent decades
- •Non-residential fathers can still be deeply involved; involvement isn’t a binary
- •Bonding isn’t limited to the first hours/days—adoptive/step-parents can form strong bonds later
- •Practical takeaway: sustained participation in a child’s development enables attachment at many ages
- 38:50 – 50:25
Hormones and hands-on fathering: testosterone drops, reduced risk-taking, and the supplementation tradeoff
They unpack how fathers’ testosterone tends to decline with caregiving, aligning with the ‘challenge hypothesis’ observed across species: shifting from mate competition toward nurturing and safety. Chris and Saxbe also discuss concerns that testosterone supplementation could undermine patience and caregiving adaptation, reframing masculinity as flexibility rather than chronically high T.
- •Testosterone decreases are linked to caregiving time; without care, changes are weaker
- •Lower T is associated with reduced aggression and risk-taking, stronger pair-bond investment
- •Hormones are context-responsive; biology and culture interact to shape fathering
- •Potential concern: T supplementation may blunt caregiving adaptation—needs rigorous research
- 50:25 – 1:00:48
More kids and the ‘daughter effect’: second-baby brain changes and early evidence dads struggle more with girls
They review limited research on brain changes with subsequent children: a second pregnancy can trigger new shrinkage patterns associated with task-switching and managing multiple demands, alongside partial rebound over time. Saxbe also shares new lab findings: fathers of daughters show larger testosterone drops, less caregiving time, more stress, and weaker bonding in early months—raising questions about expectations and socialization.
- •Sparse literature suggests a U-shaped brain trajectory: shrink, partial rebound, then new tuning
- •Second-child changes may target multitasking/task-switching networks for multiple-kid demands
- •Twins/triplets are under-studied but could reveal ‘dose’ effects and increased dad involvement
- •New data: dads of daughters show bigger T drops, less caregiving, more stress, worse bonding—mechanisms unclear
- 1:00:48 – 1:03:43
Housework, cortisol recovery, and stress contagion: how couples biologically amplify or buffer each other
Saxbe describes her dissertation work tracking dual-income couples’ time use and cortisol rhythms, finding evening housework predicts poorer cortisol recovery. She then explains ‘stress contagion’—partners’ cortisol levels co-vary, especially in conflicted relationships—highlighting communication as a biological intervention lever.
- •More housework time correlates with less end-of-day cortisol decline (worse recovery)
- •Moms’ cortisol improves when dads do more housework; dads benefit when they get more leisure (asymmetry)
- •Stress contagion: partners’ cortisol levels rise and fall together
- •Higher conflict tightens cortisol linkage; better communication can turn partners into buffers, not amplifiers
- 1:03:43 – 1:15:27
Perinatal depression in dads and moms: backlash, screening gaps, and why support must be family-wide
They tackle whether dads can have ‘postpartum’ depression, with Saxbe preferring ‘perinatal’ but arguing semantics shouldn’t block support. After reviewing a viral clip and hostile comments, they emphasize mental health as a family system: dads’ wellbeing predicts maternal wellbeing and child outcomes, and fathers are rarely screened despite meaningful prevalence.
- •Dad depression prevalence ~10% vs ~19–21% in moms; base rates are also higher in women generally
- •Shared risk factors: sleep loss, stress, relationship conflict, identity strain, hormone/brain changes
- •Online gatekeeping can block care; support should not be a zero-sum ‘attention’ resource
- •Couples’ depressive symptoms correlate; one well partner can buffer the other
- 1:15:27 – 1:18:56
Why postpartum depression happens: evolutionary mismatch, isolation, and policy/social-support interventions
Saxbe argues postpartum depression is unlikely adaptive and may reflect mismatch: humans evolved cooperative breeding with extensive support, while modern nuclear families are isolated and under-resourced. They discuss evidence that paternity leave reforms improve maternal mental health outcomes, that socioeconomic disadvantage raises risk, and that mapping/activating social support networks is a practical preventive tool.
- •Mismatch hypothesis: modern isolation and pressure on nuclear families replaces communal caregiving
- •Lack of paid leave (maternity/paternity) and early return to work increases strain and risk
- •Policy evidence: expanded paternity leave correlates with improved maternal mental health indicators
- •Interventions: build a ‘social support map,’ proactively assign helpers to tasks, and normalize asking for help
- 1:18:56 – 1:34:20
Best and worst advice for new dads: grace, competence-building, and valuing fatherhood across stages
In closing, Saxbe advises dads to expect transformation and difficulty, reject myths that men are inherently useless with babies, and focus on practice-driven competence. She argues dads matter well beyond infancy—including school age and adolescence—and that dismissive cultural advice deprives men of the opportunities needed to become effective, confident caregivers.
- •Best advice: give yourself grace; expect disruption; competence comes from practice
- •Reject ‘dads are useless’ narratives—men can build caregiving skills and biology adapts
- •Father contribution isn’t limited to infancy; later stages can be equally important
- •Worst advice includes ‘a baby will fix your relationship’ and ‘keep dads at a distance’
