Variation in Human Mate Choice: Simultaneously Investigating Heritability, Parental Influence, Sexual Imprinting, and Assortative Mating

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Variation in Human Mate Choice Simultaneously
Investigating Heritability, Parental Influence,
Sexual Imprinting, and Assortative Mating

• By Phillip Skaliy

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Terms

• Assortative Mating the frequency at which
  individuals mate with persons of similar
  phenotype (positive assortative mating) or
  different phenotype (negative assortative mating)
• Sexual Imprinting - individuals acquire
  mate-choice criteria during development by using
  their opposite-sex parent as the template of a
  desirable mate
• MZ monozygotic (identical twins)
• DZ dizygotic (non-identical twins)

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Overview

• Human mate choice is essential to evolution
• Basis of variation in mate choice is not well
  understood
• Look at twins, partners, parents
• Test for genetic and family environmental
  influences on mate choice
• Different traits analyzed
• Test for sexual imprinting

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Background

• Studies before this
• Romantic partners correlate positively on age,
  social attitudes, and religiosity
• Believed that similarity between partners is due
  to initial choice (assortative mating)
• Conflicting results why do we choose a
  particular mate over another
• Constraints of mating market
• Could be genetic or non-genetic

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Background

• Possible non-genetic/environmental factor is the
  influence of Parents on mate decision
• Ensure daughters marry successful men
• Sexual Imprinting
• Opposite sex parent as template for mate
• Traits looked at
• Education, yearly income, Religiosity, Social
  attitudes, Personality, Height and age, Body mass
  index (BMI), Length of relationship

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Experiment

• Non-genetic
• it should be revealed in a twin study as a family
  environmental effect on females for mate choice
  regarding investment-related traits.
• Genetic influences
• See if there is any similarity or correlations
  between the twins spouses and see if there is a
  difference between the spouses of MZ and DZ twins
• Sexual Imprinting
• Twins partner should be more similar to the
  twins opposite-sex parent than to a co-twin or a
  same-sex parent

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Table One

• 22,861 individuals from 6,105 independent
  families

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Table 2

• In this table it is clear that twins partners
  were not more similar in any trait to the twins
  opposite-sex parent than to the twins same-sex
  parent. Thats a strike against the imprinting
  thesis.

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Table 3

• Table 3 shows that partners correlated very
  weakly on some traits (e.g., income and
  personality) but strongly on others (e.g.,
  religiosity and attitudes).

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Table 4 - shows the correlations between twin
pair partners on each trait

• Notice that theres not a difference between MZ
  and DZ females for income.

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From the tables

• Twins Partners correlated weakly on most traits
  but positive on some
• Correlation between twin pair partners was not
  significant for BMI, height, and all personality
  scales, but there were small but significant
  correlations between twin pair partners for
  education, income, religiosity, attitudes, and
  age.
• Tested to see if there was a difference between
  MZ and DZ partners, but there was none
  (correlation not higher in MZ)
• indicates no significant genetic influence on
  mate choice

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From the tables

• Specifically for income and age, correlations
  between female MZ and DZ twin pair partners were
  highly significant and similar in size,
  indicating a genuine family environmental
  influence on womens mate choice for these traits
  even after controlling for assortative mating
• There was no evidence for the sexual imprinting
  hypothesis.
• A twin's spouse was much more similar to the twin
  and co-twin than the twin's opposite-sex parent.
• For the heritability of each trait, twin pair
  correlations were significantly greater for MZ
  pairs than for DZ pairs

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Discussion

• Overall, found that genetic variation accounts
  for very little individual variation in human
  mate choice.
• Twins partners correlated very little
• Furthermore, there were no significant genetic
  effects on mate choice in either males or females
  for any individual trait.
• it is remarkable that a choice behavior so
  central to individuals lives exhibits a
  near-zero genetic component
• But choice of mate requires reciprocity

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Discussion

• One positive finding in the results is an
  influence of family environment on female mate
  choice in terms of the income and age of a
  partner
• parental influence is expected to primarily
  involve pressure on a daughter to mate with
  successful man
• There was little evidence for substantial
  familial effects on other aspects of mate choice.
• Main conclusion Despite being one of the most
  important choices in human life, variation in
  partner choice followed no apparent order aside
  from a small family environmental influence on
  the age and income of females mate choices and
  the similarity of partners in some traits.

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Improve Study

• Study different traits pheromones, facial
  characteristics
• Look at newlyweds and see if there is a
  difference
• Done in Australia different environmental
  influences

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References

• http//www.britannica.com/EBchecked/topic/39494/as
  sortative-mating
• http//blogs.discovermagazine.com/gnxp/2011/04/lov
  e-is-not-a-hardwired-battlefield/
• http//www.jstor.org.pallas2.tcl.sc.edu/stable/10.
  1086/659629?SearchyessearchTextchoicesearchTe
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