Lecture 4 (Intrasexual Competition 1) - Slides Flashcards Preview

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Intrasexual Competition
(also goals)

- Competition WITHIN the sexes for access to mates
- Remember Bateman Principle: Sex with more variance in RS will compete for access to the sex with less
- Goes: 1) Exclude men from the competition, 2) Make yourself more appealing to the selecting sex.


Male Intrasexual Competitions

- Men compete through:
1) Dominance Competitions: Through direct aggression (force or threat of force), or status/positional goals.
2) Sperm Competition


Threats of Force

- Might be better to threaten because direct competitions are extremely risky.
- Better to seem like you can win because it's safer
- Physical aggression can be prevented by cues to dominance.


Dominance Competitions

- Behaviour where the apparent intent is to achieve or maintain status through force/threat of force and socially/physically
- Winning = increase status. Winning also increases T
- Status means access to resources desired by mates which promotes evolution of ornaments and weapons
- Winning also means excluding males from: receptive females, positions of high status and access/control to resources that are attractive to mates


Cues to dominance

Posture (taking up lots of space), facial expression (dominant smile less), eye contact, height, muscularity, walking speed (dom walk faster), VP, face


West Point Cadets (Mueller & Mazur, 1996)

- Facial dominance assessed in cadet year book. Tracked likelihood of promotion in their career based on facial dom
- Dominant appearance: Promoted to high rank earlier at all life stages and predicted fitness except in highest achievers who had less children (because they are at their job more)
- Some Submissives were promoted earlier possible because they may be good at pleasing doms



- When someone looks at something we may follow their gaze to see what's going on.
- Gaze congruent: if you look at a face and their gaze was going toward a dot that was presented earlier
- Presented at different time intervals
- Individuals reaction time was much faster when looking at dominant individuals in short time intervals.
- Not for longer because we ignore information when exposed to it for long enough


Facial Masculinity
(Watkins et al., 2010)

- Rated faces on dominance
- Self-rated dominance was also scored
- Masculine faces are rated as more dominant and especially by submissive men. Submissive men are more sensitive to dominance cues


Voice Pitch and Competition
(Puts et al 2006)

- Recorded voice
- Told they would compete with another man for a lunch date with a woman in a third room.
- Recorded responding to competitor why might he be respected or admired by other men and scored based on social/physical dominance
- Men who thought they were more physically dominant than the competing male lowered their VP and less raised it.


3 Predictions of Force (Predictions for when it might happen)

1) Risky competition should be more intense in males
2) intensify when males are seeking access to females
3) intensify when males are less able to attract females


Homicide (how it satisfies the predictions of force)

- Men more likely to kill and get killed
- Young Male Syndrome: After puberty starts, males spike in homicide rates until 40s
- Occurs in all cultures and since the 20s
- Satisfies first force prediction
- Married men kill unrelated men less than if they are single and divorced and windowed is very high
- Occurs across all age groups
- Satisfies second prediction
-Homicide occurs more in unemployed across all ages
- Gini inequality predicted homicides in a large group
- Satisfies third prediction


Dominance Competitions
(positional goods?, testosterone)

- Less costly strategies
- Compete for status and resources that attractive to women
- Positional Goods: Signal resource availability through open displays of resources or status.
- Men are more likely to keep up with technology because it's perceived as a status symbol (Watches, clothing, technologies, cars)
- Testosterone: Facilitates competition and mating. Successful attempts at competition increase T and it doesn't matter what it is. Defeats = decreased T. Also increases when their sport team wins


Saad & Vongas, 2009

- Measured T before Ss got into porche or clunker.
- Drove downtown and on the highway, counter balanced, measured T in between.
- Didn't matter where Porche drove, it raised T, clunky had no effect but could even lower T


Griskevicius 2009

- Subjects read 1 of 3 scenarios:
1) Competition
2) Courtship
3) Control
- Then introduced with the scenario, "Someone spills a drink on you and does not apologize" - one type of competition leading to another
- Measured direct/indirect aggression
- Cues to competition increase later direct aggression in males
- Cues to competition and courtship raised aggression levels in females.
- Courtship cues are lower in males, because males may inhibit direct aggression when the audience is female and not perceived as a good mate
- When aggression is indirect, female aggression is extremely high.
- Status competitions can ignite direct aggression among males
- Motive and audience influence (men inhibit aggression among females) likelihood for direct aggression in males, but not indirect and for males only.


Sperm Competition
(What kind of adaptation and why?)

- Compeition between sperm of different males to fertilize females
- Measured by sperm swimming speed
- But also <5 days in the cervix with very low odds.
- Can cause the chance that an offspring is either males within that window.
- Can be known that a female is fertile (overt) or hidden (concealed) as a way to influence investment in males
- 9-25% of females have more than one partner.
-Baker & Bellis (1993) - See flashcard
- Psychological Adaptation: Increased duration of partner absence is associated with: Increased male sexual interests, persistence, distress at refusal.
- 35% of all sperm are lost
- Sexual preferences are adaptations (Pound 2002)


3 Types of Double-matings

1) Cryptic Polyandry
2) Overt Polyandry
3) Forced Copulations


Baker & Bellis 1993

- Time a couple spent together since last copulation & Sperm count at couples next copulation
- 100% time = 319 million; 5% = 712 million
- Extrapair cop(EP): 5% increased sperm retention, and often occur in late follicular phase


Pound 2002

- Rated 16000 pornographic images/videos/stories
- Polyandrous (many males/1 female) preferred 2x more than many females 1 male
- Why? Men that do not prefer poly androus would not physically engage in that scenario
- If this female is having many male mates, it's best to give as much as you can since it's cheap because you can't win the race if you don't run.
- Sexual preferences are adaptations and men appear psychologically prepared for instances of polyandry.



- Sex Differences in intrasexual competition arise from differences in reproductive constraints
- Men compete with direction aggression, statust seeking, sperm competition