Transcript The Puzzle of Monogamous Marriage

Joseph Henrich, Robert Boyd, and Peter J.
Richerson (2012). The puzzle of monogamous
marriage. Philosophical Transaction of the Royal
Society, 367: 657-669.
• Number of wives associated with power and wealth with
more wives meaning greater power and wealth.
• With greater inequality of wealth, polygyny becomes
more common among those with greater wealth.
• In high competition situations, unattractive low-status
males will engage in more risky behavior to avoid fitness
oblivion (not mating).
• In low competition situations, status gains do not lead to
greater reproductive success and thus a male will be
more adverse to risk and more likely to pair bond.
• Females generally seek higher status males.
• Distinct from mating strategies.
• Part of cultural learning and cultural norms.
• Failure to adhere to norms can cause an individual to be
outcast.
• The modern package of norms and institutions that constitutes
monogamous marriage has been shaped by cultural evolution
driven by inter group competition.
• Because…
• Monogamous marriage reduces the intensity of intra sexual competition.
• Normative monogamy reduces intra household conflict.
• Examination of evolution of Mormon communities that
adopted normative monogamous marriage over
polygamy.
• Cross-sectional analysis of several nations with different
normative marital practices.
• Imposition of normative monogamous marriage decreases intra
sexual competition.
• Lower rates of crime.
• Reduced spousal age gap, gender inequality, and fertility.
• Increased GDP per capita.
Normative monogamy reduces intra-household conflict.
• Greater paternal investment and elimination of conflict between co-wives.
• Normative monogamous marriage likely spread due to its
impact on intergroup competitive success.
• Decreased crime likely spurred commerce, travel, and free flow of ideas
and innovations.
• Low status males would be more likely to marry and more likely to look to
the future rather than engage in status elevating risky behavior.
• Higher status males would invest more in children rather than the addition
of wives which would lead to better education and advancement of
society.
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