I must admit, although it is a bit "mean," I rather liked the hypothesis that Leftism is a product of mutational load, the idea that the present social order favours those who have a genetic propensity of Leftist ideals. They secure resources and can reproduce, those not gays maybe, and so the population gradually becomes Leftist. Noah Carl and Bo Winegard offer the critique of this idea below. It is technical, but their basic point is that those advancing the mutation hypothesis argue that Leftism is associated with factors such as mental illness. But they counter this with the usual biodiversity obsession, the IQ of Leftists tends to be higher than that of conservatives. Well, IQ and all sorts of mental illnesses are correlated as well, but let's run with their claim.
Even assuming the higher IQ on average of Leftists (which is probably a sample bias, as the populations being tested are going to be urbanites, and hence mainly Leftists), that does not show that all the other negative traits that have been shown to be associated with Leftism, such as mental illness, do not count. In fact, these negative factors will have selection pressure against Leftism in the case of social breakdown. The supposed IQ differences between conservatives and the Left are not sufficient to have a survival effect in the case of breakdown, and the urban over-intellectualisation of the Left, creatures of urbanisation, will definitely count against them in survival situations.
Thus, I think once the IQ issue is dumped, the Leftism as a product of mutation is still a viable hypothesis.
https://www.aporiamagazine.com/p/can-mutation-load-explain-the-rise
"In a recent article in Aporia, Joseph Bronski and Matthew Archer argued that the rise of leftism since 1960 is partly explained by mutational pressure in the gene pool. Elsewhere, Bronski has gone as far as suggesting that "Western political change is solely due to evolutionary pressure" – by which he means a combination of mutational pressure (favouring leftism) and selection pressure (favouring rightism).
This is certainly an interesting and provocative thesis. If true, it would upend our understanding of changes in the political landscape over the last sixty years. But is it true? We are not convinced. In the remainder of this article, we will lay out reasons why. Note that Arctotherium has already published a three-part critique of the mutational load hypothesis which we would recommend reading.
Mutational load and leftism
The mutational load hypothesis makes two key assumptions:
1. Mutational pressure has increased over the last sixty years (due to a combination of rising parental age and declining infant mortality).
2. Mutational load causes leftist political beliefs. The first assumption seems highly plausible. The second, however, demands closer scrutiny. As evidence in favour of the assumption, Bronski points out that leftism is correlated with paternal age and mental illness – two potential proxies for mutational load. A major problem with his theory is that there's another potential proxy for mutational load, namely IQ, which is positively correlated with certain leftist beliefs.
What makes IQ a potential proxy for mutational load? Well, it is positively associated with indicators of physiological integrity such as grip strength and longevity. It is negatively associated with indicators of developmental instability such as various measures of fluctuating asymmetry. And individual differences in IQ are partly explained by rare, presumably deleterious, mutations. Bronski conceptualises leftism in terms of one's views on three issues: women, homosexuals and racial minorities. He hypothesises that individuals with more "leftist" (i.e., less socially conservative) views on these issues have higher mutational load. Since IQ is an obvious potential proxy for mutational load, his theory predicts that such views should be negatively correlated with IQ. The problem is that studies consistently find the exact opposite. A 2015 meta-analysis analysed 67 studies and found an average correlation between IQ and social conservatism of r = –.20. The relationship between IQ and political beliefs does vary depending on the issue: measures of fiscal conservatism are often associated with higher IQ. Yet measures of non-traditional attitudes to women, homosexuals and racial minorities are invariably associated with lower IQ. They are even associated with DNA-based predictors, suggesting that IQ actually causes such attitudes. To take just one example: in the US General Social Survey, whites who score 0–1 out of 10 on the Wordsum vocabulary test are 33 percentage points more likely to say homosexuality is "always wrong" than whites who score 9–10 out of 10.2 Which group is likely to have higher mutational load: the one scoring 0–1 or the one scoring 9–10? Surely, the former. Perhaps mutational load causes social conservatism. …
The negative association between IQ and social conservatism casts serious doubt on the claim that mutational load causes leftist political beliefs – especially if we define leftism as non-traditional attitudes to women, homosexuals and racial minorities.
Cohort or period? It is clear that most Western countries, not least the US, have become more "leftist" (i.e., less socially conservative) over the last sixty years. The question is why? We can distinguish two broad classes of explanation: period effects and cohort effects.
Period effects involve multiple cohorts within the population simultaneously shifting their views. For example, suppose we have three groups: young, middle-aged and old. A period effect would be where all three groups become, say, 10% of a standard deviation more leftist – and as a result the overall population
becomes 10% of a standard deviation more leftist. In the case of period effects, individuals actually change their views during the course of their lives.
Cohort effects, by contrast, involve the gradual replacement of cohorts with one set of views by cohorts with a slightly different set of views. Go back to the three groups. A cohort effect would be where the middle-aged turn out to be 10% of a standard deviation more leftist than the old, and the young turn out to be 20% of a standard deviation more leftist – and as a result the overall population becomes 10% of a standard deviation more leftist. In the case of cohort effects, individuals' views are fixed once they are formed.
It should be obvious that any explanation for the rise in leftism that invokes genetic changes must posit cohort effects: changes that accumulate generation by generation cannot cause multiple cohorts to simultaneously shift their beliefs. The problem for Bronski's theory is that studies attribute a sizeable part of the rise in leftism to period effects.
A comprehensive review of the literature is beyond the scope of this article, but suffice it to mention a few recent papers. David Ekstam examines change in attitudes to homosexuality and concludes that "both period and cohort effects have contributed to the increase in tolerance over the past three decades". Jean Twenge and colleagues examine increased support for gay marriage between 1988 and 2004–2018 and conclude that it was "primarily due to time period". Likewise, Ashley Kranjac and Robert Wagmiller examine change in attitudes to homosexuality and conclude that "both intracohort and intercohort change played positive and significant roles in the liberalization of attitudes".3 Elizabeth Curry examines change in attitudes to homosexuality in Britain. She finds that while "there is evidence of the rise in support … being driven by generational replacement", there is "also considerable evidence of a societal effect".
Technically, the pattern … could be explained by a combination of cohort and age effects, but that would mean people become more tolerant of homosexuality as they got older. This is contrary to analyses of panel data, which find that people rarely get more liberal as they age (after taking time period into account).4
Studies from East Asia also find large period effects on attitudes to same-sex relationships. Rei Naka's analyses of Japanese data "highlight the role of intracohort change in liberalizing attitudes toward homosexuality". And in Zhiyong Lin and Jaein Lee's models of attitudes toward homosexuality in South Korea, "the period effects dominated".
The evidence reviewed above is not inconsistent with a weak version of Bronski's thesis whereby the rise of leftism is partly explained by genetic changes, but it does contradict the strong version whereby the rise of leftism is "solely" explained by such changes.