Got that? You’re sure to graduate in evolutionary psychology:
From a computer model from the University of Waterloo:
The study, by Professor Bauch and Richard McElreath from the Max Planck Institute for Evolutionary Anthropology, found that when population sizes become large, the presence of STIs decreases fertility rates more among males with multiple partners, therefore changing which mating behaviour proves to be most beneficial to individuals and groups.
Reality: The only consistent enforcer of monogamy has been the relatively equal number of boys and girls born.
In early hunter-gatherer populations, it was common for a few males to monopolize mating with multiple females in order to increase their number of offspring. In these small societies where there is a maximum of 30 sexually mature individuals, STI outbreaks are short-lived and tend not to have as significant an effect on the population.
That is according to those guys’ computer model. We do not know what happened in thousands of individual small societies.
However, as societies evolved around agriculture and group sizes grew, the research predicts that prevalence of STIs increased amongst polygamist networks that overlapped. With the absence of modern medicines, infertility from syphilis, chlamydia and gonorrhea would likely have been high. This made it more advantageous for males to mate monogamously, and more importantly, to punish other males who did not. Groups that enforced monogamous social norms could therefore outcompete groups lacking such norms. More.
Do we know that all STDs were ubiquitous? They probably weren’t. See this controversy around syphilis, for example.
Serious discussion of the social problems around polygamy may follow from the demise of evolutionary psychology, but won’t precede it.
Now, getting a job to pay your debts for all this enlightenment… um… that’s a bit of a stretch. Why is evo psych almost indistinguishable from pop culture mags and airhead TV? Can’t be a random effect.
See also: “The evolutionary psychologist knows why you vote — and shop, and tip at restaurants”
Note: Serious teachings on monogamy tend to be theological, a far cry from evo psych and airhead TV: