Variation in Human Mate Choice: Simultaneously

Investigating Heritability, Parental Influence, Sexual

Imprinting, and Assortative Mating

By: Phillip Skaliy

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)

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

Background

Studies before thisRomantic partners correlate positively on age, social

attitudes, and religiosityBelieved that similarity between partners is due to

initial choice (assortative mating)

Conflicting results – why do we choose a particular mate over anotherConstraints of mating marketCould be genetic or non-genetic

Background

Possible non-genetic/environmental factor is the influence of Parents on mate decisionEnsure daughters marry successful men

Sexual ImprintingOpposite 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

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

twin’s spouses and see if there is a difference between the spouses of MZ and DZ twins

Sexual Imprinting Twin’s partner should be more similar to the twin’s

opposite-sex parent than to a co-twin or a same-sex parent

Table One

22,861 individuals from 6,105 independent families

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. That’s a strike against the imprinting thesis.

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).

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

Notice that there’s not a difference between MZ and DZ females for income.

From the tables

Twin’s 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

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 women’s 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

Discussion

Overall, found that genetic variation accounts for very little individual variation in human mate choice.Twin’s partners correlated very littleFurthermore, 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

DiscussionOne positive finding in the results is an influence

of family environment on female mate choice in terms of the income and age of a partnerparental influence is expected to primarily involve

pressure on a daughter to mate with successful manThere 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.

Improve Study

Study different traits – pheromones, facial characteristics

Look at newlyweds and see if there is a difference

Done in Australia – different environmental influences

References

http://www.britannica.com/EBchecked/topic/39494/assortative-mating

http://blogs.discovermagazine.com/gnxp/2011/04/love-is-not-a-hardwired-battlefield/

http://www.jstor.org.pallas2.tcl.sc.edu/stable/10.1086/659629?&Search=yes&searchText=choice&searchText=variation&searchText=mate&searchText=human&list=hide&searchUri=%2Faction%2FdoBasicResults%3Fla%3D%26wc%3Don%26acc%3Don%26gw%3Djtx%26Query%3Dvariation%2Bin%2Bhuman%2Bmate%2Bchoice%26sbq%3Dvariation%2Bin%2Bhuman%2Bmate%2Bchoice%26prq%3Dhuman%2Bvaritation%2Bin%2Bmate%2Bchoice%26si%3D1%26jtxsi%3D1%26jcpsi%3D1%26artsi%3D1%26so%3Dnew%26Go.x%3D0%26Go.y%3D0%26Go%3DGo%26hp%3D25&prevSearch=&item=6&ttl=5299&returnArticleService=showFullText&