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It is possible that genius may be a consequence of a 'perfect storm' of several independent causes coming together rarely. For example high ability (especially general intelligence), high creativity, and strong motivation directed in-line with ability and creativity - these are each relatively rare, and in combination very rare in indeed.
(Plus, there may need to be other factors.)
But the average sub-replacement fertility of geniuses (due to their relatively low interest in social and sexual gratification which is both the reciprocal of their high interest in 'their subject' and also the need to tolerate/ welcome considerable solitude and independence); means that the lineage of a one-off genius will most likely go extinct.
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The existence of a single genius therefore probably (usually) does not create any greater chance of a genius to follow - since the number of copies of the causative genes (whatever they are) is no greater after the genius has died than before he was born.
However, when there are several geniuses that happen to be born at the same time, and in the same field - and when this field is one that increases the efficiency or effectiveness of the essentials of human survival and reproduction - e.g. breakthroughs in food production, industrial production, transport, weaponry, social organization... then these several geniuses may enable the total population to grow in such a way that there are more and more copies of the genes which (in rare combinations) lead to genius.
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In these circumstances, the existence of several geniuses in a single generation number one may lead to even more geniuses in generation number two; and this amplification could continue if the population continues to expand (and if other factors remained constant).
It is possible that something of this kind happened through the 1700s and the early 1800s in the populations of Western and Central Europe - for example, several or many geniuses emerged in the domain of agriculture and food production from the 1700s in England; and in combination led to an increased productivity per worker and more than doubling the output of food by the mid 1800s - these changes freeing labour for industry and both enabling and kick-starting the industrial revolution.
The result was that the population of England doubled from about 1700 to 1820, which would mean that - all else being equal, there would be twice as many genes for genius in 1820 as there had been in 1700. This would tend to sustain the production of English geniuses, and maintain the 'golden age' of English high achievement.
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However. we know that other factors were operating from about 1800 which would tend to reduce the proportion of geniuses in the English population; notably the decline of general intelligence ('g' which is implied by the slowing in reaction times measurable through the twentieth century). These adverse trends were probably due to a combination of differential reproduction against intelligence (an inverse correlation between intelligence and fertility) plus, and probably more importantly, a dysgenic accumulation of deleterious mutations caused by the relation of mutation filtering mostly caused by the sharp decline in child mortality rates.
So, the first effect of the perfect storm of English geniuses was to expand the population and thereby increase the number of English geniuses; but as the generations went by, the adverse selection factors and mutation accumulation would have 'sabotaged' the expansion of geniuses by reducing the average intelligence in the population - and firstly the proportion and then the actual number of people of very high intelligence, so that the number of new geniuses occurring dwindled into again being extremely rare and 'one off'.
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