I was talking with Michael A Woodley yesterday, and he told me of yet more research evidence in the pipeline to support our hypothesis that modern men are suffering from more than a century's worth of mutation accumulation.
This follows-up on our work of three years ago when we discovered that simple reaction times had slowed substantially since they were first measured in the late 1800s - and that this indicated that general intelligence must therefore also have declined substantially over that period.
This decline could partly be accounted for by the inverse correlation between intelligence and fertility but this mechanism alone was insufficient to account for the magnitude of the reduction in intelligence.
We hypothesized that mutation accumulation might be the other main cause. This is almost certain to have been happening for about 150 years, as child mortality rates have declined from historical levels of a half or more to just a few percent. Hence the primary mechanism for purging the gene pool of spontaneously-occurring mutations - of which there are probably many in each generation - has been all-but eliminated.
Early indications were that this was indeed the case:
Michael has now unearthed confirmatory evidence of mutation accumulation using a completely different measure and in an independent population (paper prepared for submission, but still confidential).
It is becoming hard to avoid the conclusion that we have been, for several generations, living in what WD Hamilton (in Narrow Roads of Gene Land, Volume 2) called the Planetary Hospital - in other words, a world in which almost everyone is suffering from significant genetic damage, and an increasing proportion of the population are suffering from genetic disease.
This raises the possibility that some or much of the social pathology in The West, including the general mainstream attitudes to this social pathology, may be attributable - in part, at least - to the accumulation of endemic genetic damage.
Is this plausible? Against it is the greatly increased Western life expectancy; but in favour of it is the ever reducing fertility - which mostly reflects an ever reducing desire for people (especially women) to have children - with fertility rates well below replacement levels despite unprecedented prosperity. And biological fitness is about reproductive success, not life expectancy.
But superficially, aside from a possible increase in 'autistic spectrum' disorders, there is no obvious epidemic of innate genetic disease among the native Western population. However, there is evidence of behavioural maladaptiveness - behavioural change which would (under ancestral conditions) lead to reduced reproductive success.
The subtlest and most easily-damaged human traits are social and sexual behaviour; and here there are very obvious changes which would tend to be net maladaptive. These might include a reduction in average self-preservation, bravery and ability to deploy violence among men to the extent of a near-suicidal passivity in the face of danger and indifference to the prospect of genetic extinction.
And among women an indifference to having children, rearing children; and the embrace of fashions which signal (according to innate signalling mechanism) sexual promiscuity and the presence of disease (eg deliberate, usually asymmetrical skin lesioning by piercing and tattoos - which mimics pathology).
In terms of sexuality, as well as the widespread embrace of non-reproductive sex in many manifestations, what is perhaps even more striking is the bland social indifference to this.
Indeed, what is most distinctive of all is an inversion of mainstream attitudes concerning sexual pathologies (by 'sexual pathologies' are meant those sexual practices which biologically impair net reproductive success). For perhaps the first time in human history, we are approaching the situation in which non-reproductive sexual practices are becoming the officially-sanctioned 'norm'.
The fact that traditional religion is an effective antidote to these trends indicates that biology is not the whole story by any means - and the abandonment of religion must bear a great deal of responsibility.
However, the abandonment of Christianity in the West may, to some extent, have been driven or more likely facilitated by changes in disposition (in attitudes, motivation etc) that are themselves a consequence of (mostly) sub-clinical genetic pathologies (ie. mostly-subtle impairments to social and sexual behaviours) due to mutation accumulation.
So, the current scenario - unrestrained as it is by the compensatory wisdom of traditional religion - increasingly resembles Hamilton's Planetary Hospital with more-or-less sick people in a majority; to the point of generating an inverted ethic in which sickness is seen as not just normal but good: a world of sick people (in effect) trying to induce as many others as possible to share their sickness (presumably so the sick will not be relatively disadvantaged).
Of course, this situation cannot long persist; not least because the sick need healthy people to look after them. But in the meantime, we have an extraordinary situation of the (indirectly) suicidal policy of promoting sickness.
This is probably unique in world history, because never before have child mortality rates been so low for so long; and never before has mutation accumulation been able to become so advanced - due to the soft, comfortable, prosperous life bequeathed to us by our recent ancestors.
Note added: According to WD Hamilton, when someone has a large accumulation of deleterious mutations, this will typically reduce the desire to reproduce. This impaired libido will presumably be partly from feeling ill and lacking energy; but also, and importantly, probably as a built-in, evolved, species-benefiting trait which is actually designed to reduce the mutation load in the relevant gene pool. In effect, the individual sacrifices his own reproduction for the benefit of his genetic relatives or group (indeed, this trait may be necessary for the evolution of complex brained species, such as humans, where mutations have exceptionally large scope for causing significant functional damage). This tendency to 'reproductive suicide' of the unfit would normally be a beneficial trait; however, when there is a heavy mutation load spread through the whole population, then this trait will lead to population reduction and eventual extinction; since too many individuals opt not to reproduce.