Conflict between the sexes. Flashcards
How is Sexual selection mutualistic in some respects.
Intrasexual competition: Good to lower-PI sex to win contests, good for high-PI sex to end up with the winner.
Intersexual choice: good for lower-PI sex to be chosen, and for higher-PI sex to choose the best one.
Mating is also not always harmonious.
Across species, many adaptations benefit one sex at the expense of another.
Males can be adapted to take more sexually than females prefer to give (sexual coercion).
Females can be adapted to extract more investment than males want to give. - these adaptations can be anatomical (part of body) or psycho-behavioural.
Further, each sex can evolve counter-adaptations to avoid exploitation by the opposite sex. = Red Queen arms races.
“It takes all the running you can do to stay in the same place”.
Example of red queen competition in sexual coercion context:
Water striders males mate forcefully with females.
Female counter-adaptation - shield over genital opening which she can choose when to open.
Male counter-counter adaptation - intimidation tactic where male taps the water near the female to attract predators, until she opens the shield.
Male sex coercion -
In many taxa, psycho-physical adaptations for sexual coercion may allow males to overpower females.
Physically aggressive mating, especially common orangutans.
Anatomical adaptations include hooks, suction cups, genital locking mechanisms for seizing females - so she stays in place durin copulation.
Bedbug phallus stabs sperm through the females abdomen.
Bypasses genitalia, gets closer to ovaries than competitors.
Infanticide can also be seen as sexual coercion.
Infant loss triggers oestrogous, reproductive opportunity for male.
Female forceful extraction of male investment:
Sexual cannibalism -
In various species of insects, females eat the males after copulation.
E.g. black widow.
In theory this could actually benefit the male too (no other pI to offer except self as food). - however, probably usually involuntary.
Mantis females also eat males after copulation - males avoid hungry lookg females.
Female promiscuity as a counter-strategy against infanticide.
Mating with multiple males in the troop has the effect of causing paternity confusion.
Every male who has mated with this female believes that the offspring could be his, reducing their incentives to engage in infanticide.
‘Strategic interference theory’.
Men and women have different mating strategies; each may have interest in blocking others strategy.
E.g. use of deception/coercion to undermine mate choice preferences of opposite sex.
Men tend to overestimate women’s sexual interest:
Reflects males’ strategic interest in havin gsex sooner, females in waiting for commitment signals.
Men and women interpret the same interaction differently:
Ppts watch video of woman asking male authority figure for a favour; males more often perceive her motives as sexual (Abbey, 1982).
This is calles ‘sexual over-perception bias’ evident in relatively egalitarian societies.
Speed dating study - men more likely to over-perceive sexual interest if they:
Are higher in sociosexuality.
Rate the women more attractive
Rate themselves more attracrtive
Similarly, women perceive men as less sexually interested than they actually are (Levesque et al., 2006).
Male sexual over-perception bias explained in terms of ‘error management’ (Haselton and Nettle, 2006).
False positive (perceiving attraction when it is not there) is less costly than a false negative (not perceiving attraction when it is there).
Missing mating opp is worse than being rejected.
Same concept as ‘smoke detector principle’.
Error management theory may also explain analogous ‘commitment scepticism bias’ in women.
Perceiving commitment when NOT there is worse than being sceptical when it IS there (Buss, 2000).
Stronger in younger women than postmenopausal (Cyrus et al, 2001).
- Commitment scepticism bias implies male deception about commitment.
Men are more likely than women to deceive about commitment.
What type of deception is most upsetting to each sex?
Women: deception about commitment and resources.
Men: sexual deception.
Sexual aggression -
Potentially imposes huge costs on women.
Women rate it the most upsetting male action (6.5 out of 7), worse than verbal/physical abuse (Buss 1989).
Men rate it 3.0 (infidelity 6.0, verbal/physical abuse 5.6).
Men believe women would rate it 5.8 - underestimate.
Male adaptation for specifically sexual aggression -
Controversial issue, in part because ‘adaptation’ label mistakenly seen as ‘validating’.
No good evidence for ‘rape adaptations’.
‘Mate deprivation’ hypothesis has found little support. - on contrary, men with more mating success are more likely to use coercive tactics (Ellis et al, 2009).
infidelity
Both sexes use mate retention techniques to deter infidelity and abandonment.
Men are more likely to mate guard when partner is ovulation (Haselton & Ganestad, 2006).
However, infidelity poses different problems for each sex.
Both sexes are threatened by both sexual and emotional infidelity, however:
Partners sexual infidelity is a bigger risk for men (paternity uncertainty).
Partner’s emotional infidelity a bigger risk for women (could lead to abandonment and loss in future) -PI.
Buss test lists over 30 studies on effects of sexual vs emotional infidelity.
Cross-culturally:
Men: greater distress to imagined emotional infidelity
Women: greater distress to imagined emotional infidelity.
Data include self report, HR, frowning, skin conductance.
Jealousy is domain-specific -
Discovery facilitated by evolutionary approach.
Sex differences had not been found with domain general jealousy, but were found with domain specific jealousy. (diffs between sexual and emotional).
Interesting cross-cultural variance in sexual jealousy -
Especially polygamous societies.
Jealousy does occur in these env’s, but the cost of jealousy is deemed to be worth the benefits.
‘Partible paternity’
in amazonas (Bari).
The belief that children can have more than one father.
If the woman has sex with multiple males during her pregnancy, the belief is that the foetus is like a vessel that can be enhanced and improved in terms of its health and viability by sperm from diff males.
Usually there is a primary father.
Retains some male PI if one father dies prematurely.
Facilitated by lack of deception; allows men to calibrate PI to paternity certainty.
Able to do this because there is no deception - person who has had sex with her the most is the primary father, as there is more paternity certainty, and so on.
In a dominance hierarchy, animals at the top have improved access to key resources.
Hierarchies are transitive (A > B > C)
Advantage to being submissive: avoid injury (and in socially complex species, avoid social costs).
Status signalled through physical gestures.
Including submissive grinning.
Dominance related colouration changes.
Dominant must constantly defend their positions, advertise formidability.
E.g. alpha chimps strut around, make nouse and make themselves look big.
Submissive chimps greet dominants with crouches, gifts, smiles and kisses - failure to display this may provoke retaliation.
In a dominance hierarchy, animals at the top have improved access to key resources.
Hierarchies are transitive (A > B > C)
Advantage to being submissive: avoid injury (and in socially complex species, avoid social costs).
Status signalled through physical gestures.
Including submissive grinning.
Dominance related colouration changes.
Dominant must constantly defend their positions, advertise formidability.
E.g. alpha chimps strut around, make nouse and make themselves look big.
Submissive chimps greet dominants with crouches, gifts, smiles and kisses - failure to display this may provoke retaliation.
Benefits of dominance are ultimately reproductive.
50-75% of chimp copulations involve the alpha, even with other males are in the colony.
During oestrus this percentage grows; subordinate sexual access is more likely outside of this.
DNA studies support the link between dominance mating and offspring in chimps and other primates.
Primate hierarchies are dynamic and unstable.
Social intelligence can be crucial to ascending this ladder.
In species that can form alliances to unseat alphas, abilities to enlist allies can rival physical size in importance (Cummins, 2005). - social intelligence.
Humans form status hierarchies quickly and easily.
Among human strangers, clear hierarchies emerge within minutes (Fisek and Ofshe, 1970).
People can predict their own place within it after only seeing members’ faces (kalma, 1991).
Human status competitions in some ways are similar to other species.
