Chapter 7 Male Sex Drive Sperm Wars (Baker, 1996) Male sexuality evolved to prevent/fight sperm warfare Maximize chance of fertilizing egg, passing genes on, & avoiding cuckoldry Penis anatomy, thrusting & rapid orgasm Routine sex & topping off Masturbation Infidelity & jealousy Penis Anatomy & Thrusting Shape/thrusting cleans out other sperm Suction Larger Rapid the greater the suction orgasm Maximized insemination Animals: Rapid insemination after infidelity Why males find pornography so arousing Penis Anatomy & Thrusting Reproductive disadvantage to male for female to have orgasm before sex Increases strength of cervical filter Males biologically destined to ‘rush’ w/o foreplay, climax rapidly Nature of Sperm Average ejaculate contains 500 million sperm 3 primary types: Killers Seek (fast, youngest, poison head) out and kill other men’s sperm Blockers Block (slow, old) other men’s sperm Egg-getters > 99% of sperm in ejaculate are killers or blockers < 1% of sperm are egg-getters Nature of Sperm Sperm 2 live 5 days in female days to peak fertility Egg dies w/in 1 day of release Male must inseminate 3-4 days < ovulation Best chance of conception if 2-3 days before Sufficient killers & blockers to win sperm war Routine Sex & Topping Off Hidden ovulation: Males consistently inseminate partner Higher sex drive Males adjust #, type sperm to keep healthy, fresh sperm in cervix (top off) Delay 5 since last sex (chance of foreign sperm?) days: 400 million 3 days: 200 million 3 hours: 30 million Routine Sex & Topping Off Critical Keep For to winning sperm wars killer, blocker sperm population high 3 days post-intercourse Aging of sperm in testes matches loss of blockers in cervix Inject exactly the right amount of blockers to top off population Routine Sex & Topping Off Columns Closest of sperm in epitidymis to testicles youngest Farthest away oldest (blockers, killers) Adjust sperm via muscular contractions, number of spurts Masturbation 98% males masturbate (3/wk, Class M = 4.89) Many mammals also Shedding Testes sperm produce 300 million sperm/day Shed 5 million/hour since last ejaculate First to be ejaculated oldest Masturbation Male body times urge to maximize chance of winning sperm wars Purpose is to tailor ejaculate for next intercourse Adjusting type, number of sperm Shedding Best old, slower sperm 2 days < insemination Many young killers & blockers Can be further adjusted depending on infidelity risk Infidelity & Jealousy Sexually jealous/possessive of partners Most jealous/in control less chance of cuckoldry More HIS genes passed on Male sexuality evolved w/ desire for numerous, fertile partners (even strangers) Item IQ Emotional Stability Honesty Wealth Health Kind Weight Religion Race Attractive Height Family Long 3.28 4.10 3.17 8.90 6.48 3.93 5.52 7.48 7.38 3.00 8.28 9.83 Short 7.07 6.34 6.07 8.14 4.10 6.10 2.69 4.19 6.24 1.24 4.93 10.17 p < .05 < .05 < .05 ns < .05 < .05 < .05 < .05 < .05 < .05 < .05 ns Male Sex Drive Men want lots of sex w/ lots of partners Relationships Men are better but still... want 50% more sex than they are having Women sex desire = actual amount Sexual Starvation Chronic sexual frustration inevitable for most men High status males may be able to achieve satisfaction (Brad Pitt, Bill Gates) Temporary Adaptation Habituate to any S intensity Taste, touch Incrementally decrease R Incrementally increase desired S Money, Sports, Drugs Lottery winners initial euphoria fades Jordan & multiple championships Pot gateway drug Adaptation Sexual Starvation Sex Virgins just want 1 Then after 1 you just want 2-3 and so on Made worse by social comparison (Festinger) Compare Men w/ others to evaluate ourselves may lie or be inaccurate Volunteers different than non-volunteers Media distorts sexual experiences of males Sexual Starvation Males will never be sexually satisfied because no matter how much sex they have they will eventually adapt & want more Doomed Sexual More to be perpetually frustrated boredom (males > females) masturbation & risky sex (prostitutes, unprotected sex, cheating) Desire for big pay-off increases risk taking Reaction Paper III: Sexual Starvation What is your reaction to the idea that men are fatally doomed to experience chronic sexual frustration, not getting enough sex even when married? How do you think this will impact the way you deal w/ relationships in the future? Conclusion Male sex drive complicated & may have evolved to prevent/fight sperm warfare One consequence is high sex drive and perpetual sexual starvation via habituation