Steven Crane Compiled Section Handouts. Human Behavioral Biology 2012

Heterozygote vigor argument

Traits that are maladaptive in males but adaptive in females

Kin selection: helper at the nest hypothesis. Evidence supports this hypothesis.

What traits are markers of a good mate?

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  Lots of support for symmetry.
  

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  Women judged to be more symetrical when ovulating.
  
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  Babies prefer symmetrical faces.
  
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  A marker of health.
  

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  Secondary sexual characteristics like lions' manes, big bushy beards, colorful bird spots, etc. Why would these be good markers for a mate?
  

• Handicap principle: I can be wasteful on these traits so I'm very fit. Lots of evidence here.

  • The worse the health and life expectancy in a country, the more women prefer faces of men with pronounced secondary sexual characteristics! Interesting, no?

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  Could be markers of immune competence. Esp with caretinoids in birds.
  

  • But males will try to cheat and put their last dying gasp of energy into their secondary sexual characteristics so they can mate before they die.

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  Markers of fertility.
  

  • Females: Like estrus swellings which indicate estrogen levels, earlier puberty, better child survival.

  • Females: Like high breast:waist and low waist:hip ratios indicating fertility.

  • Males: Like jutting jaws, high foreheads, heavy musculature indicating high T.

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  But how do these markers run into the problem of a self-fulfilling prophesy?
  

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  Take a given male bird and the females don't like him that much. But then surround him with fake female birds: make him seem all popular. Then all the other females now like him. A bandwagon effect.
  
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    Interpretation: other females recognize that this male can attract females, so offspring of this male will be able to attract females and thus have high fitness. Therefore those females will have high fitness. Has individual selection written all over it.
    

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  What features of human couples show a lot of homogamy?
  

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Religion, age, race, ethnicity, politics, SES	Shared in 90% of couples
IQ, education, introversion/extroversion	>40%
Height, weight, hair color, eye color, width of nose, length of earlobe, lung volume	<40% but still significant!

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  What did the Buss study find as to what people really want in a mate?
  

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  Women more likely than men to value financial status in a mate
  
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  Men more likely than women to value youthfulness, fidelity, and fertility.
  
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  OVERALL EVERYBODY JUST WANTS SOMEBODY KIND AND INTELLIGENT. Yay humanity.