Some inspiring ideas like this came from some combination of Michael Vassar and Peter de Blanc.
Why are Scandinavians so rational? I don’t know, but one hypothesis seems rather aesthetically pleasing. Because the Scandinavians had such crazy memes — pillaging, exploring, and just being generally reckless with their lives — there was a selection pressure for people who were genetically predisposed to sanity. All of the people with crazy genes went totally crazy when supplied with crazy memes, and probably died off in battle or when trying to cross the Atlanic or whatever. The memes stayed in equilibrium because they were pretty good memes on the societal level, even if individual Vikings had a high chance of death. Thus the selection pressure was stronger on the memetic side than the genetic side, and because there was such a large amount of selection pressure coming from the constant exploration and raiding, it was enough to drive noticeable increases in genetic predisposition to rationality in the general Scandinavian populace.
Classical reasoning about evolutionary psychology similar to the kind displayed in “The Psychological Foundations of Culture” might point towards the selection pressure not being large enough to cause noticeable difference, but I find “The 10,000 Year Explosion” to be a convincing argument that evolution on such short timescales is possible. (I don’t know what Tooby, Cosmides, or other evolutionary psychologists in general think of this model of human evolution.)
At any rate, whether or not it happened noticeably in the case of Scandinavians, we can see that such equilibria between genetic and memetic sanity could exist. This is pointed at by the theory of ontogenic evolution, better known as the Baldwin effect and the corresponding shielding effect. In this case, however, it is not the ‘natural’ environment that is throwing difficult general reasoning problems at the genes, but partially-humanly engineered memetic conditions.
The reason somewhat stable equilibria are reached is because the Baldwin effect for genes is a shielding effect for memes. Crazy memes select for sane genes, but crazy genes will also select for sane memes. The rate at which the memeplex or geneplex can adapt to the the environment and each other is what determines where an equilibrium is reached. In environments where you don’t as often encounter difficult cognitive problems there will be a stronger selection for irrational memes that satisfy other constraints, like being interesting.
Susan Blackmore introduced the concept of ‘temes’ to talk about technological replicators. They’re like memes that need not run on brains, being more universal. You could say the dangers of Seed AI are the dangers of a teme that is so good at replicating that it eats all the genes and memes for food, in much the same way that the first replicators turned the chemicals of the oceans into themselves, and the same way that memes have taken over human minds for their own various purposes.
Currently, temes aren’t all that impressive — we think our memes are smarter. But as temes get more intelligent, we might start to see selection pressures for sanity between memes and temes, both of which can evolve at a much faster timescale than genes. Having a really smart robot take care of your life means that you can spend less time following politics or keeping your arithmetic skills sharp. Because both memes and temes evolve so quickly, especially temes, I don’t think that this window of interesting equilibria will be very large as measured by the timescale of our genes. But we should note that our memes are going to have to be very sane, if we are to design temes that aren’t themselves very sane. Because we can’t rely too much on the sanity of our genes or our memes, we’ll have to spend a lot of effort on getting our temes to be as sane as possible instead. Hence we solve computational axiology as generally and completely as possible, and trust only our very safest memes.