The pattern that we see is much what one would expect of a lineage over time if, collectively, the additive genetic components of this success factor was largely passed on from one generation to the next. Indeed, it really shouldn’t be any different. The individual variation is caused by a variety of factors, including environmental “luck”, non-additive genetic effects, developmental noise, and spousal genetic contribution (which may help or hinder). But, the key point, when the whole clan is considered at once, all these sources of variance should more or less cancel out. The only thing that breeds true is the additive genetic variance, and, in any large clan, that should pass on fairly uninterrupted from one generation to the next. The whole clan’s short-term generation-to-generation variance can be caused by variation in local circumstances that may help or hinder the entire lineage. That too should, over the generations, cancel out, in good part. The success of the clan over time is then dictated by its evolutionary fitness and it the degree of assortative mating.Family = Clan = Ethnicity = Race. Jayman could be describing any of these four terms. They are essentially interchangeable, the only thing distinguishing the succeeding term from the one preceding it being size, and saying that the transition points between these terms are hazy and indistinct is a major understatement. A big, related family or group of related families is a clan; a big, related clan or group of related clans is an ethnicity; a big, related ethnicity or group of related ethnicities is a race.
Steve Sailer pithily summed this up nearly two decades ago, describing a race as an extended family with some level of in-breeding present.
From this, we discern things like what La Griffe du Lion calls the fundamental constant of sociology, the implications being, among other things, that if both a white couple with IQs of 115 and a black couple with IQs of 115 each have a child, chances are the child from the white union is going to have a higher IQ than child from the black union. It's far from certain that as much would be the case when only a single white and single black couple are being considered, but take 100 white and 100 black couples as described above, and it's virtually guaranteed that, on average, the collective white litter will have a higher average IQ.
Intelligence is just one aspect of countless other characteristics--seemingly all traits are heritable to some degree--but just this one is often too much for most polite people to handle. The truth is no less evitable in spite of them, of course.
Working from the ground up, so-to-speak, is probably the most socially and politically effective way to spread the HBD word.