I've read a bit on discovery. There are 3 main theories discussed on scientific discovery - the great genius, the cultural zeitgeist and just chance. The great genius without who history would be greatly changed was discounted on the commonality of multiple inventions and the existence of many sufficiently intelligent people at any given time. The cultural zeitgeist holds that there are many ideas in the air and one only has to look to pick it, that it is the intellectual backdrop that determines when and what gets discovered. That multiple inventions are often separated in time and not all discoverable items are found when they could be runs counter to this. The chance model suggests not all discoveries are found and scientific discovery is random as to who gets it and that it follows a Poisson distribution. In one article [1] , an example of a tree with 1000 ripe apples and 1000 apple pickers was given, how many apples are picked?How many people pick the same two or three?
A refinement of the stochastic model considers that geniuses exist but they are able to see and synthesize more than others not that they can see what others can't. They benefit from the cultural backdrop and do not innovate as islands. Their discoveries would eventually be replicated by a large number of individuals making blind turns with individual portions. In sum, not all ideas that are discoverable within a cultural zeitgeist are found, it is essentially random who discovers what but there are a few lucky individuals that tend to be over-represented [2].
How lucky? In numerous ways. In addition to having the right set of genes, epigenetic developments and beneficial stochastic fluctuations in neural development they also need the right set of skills and experiences, and then to not just pick a solvable problem but to pick one solvable by their particular mindset. Solving problems is not a deterministic process but more a sampling of a large combinatorial construction of possibilities acquired only through expertise. So there is an element of chance in fixing the right permutation of ideas. So run history twice and Einstein might not have found General Relativity. In getting recognized luck also plays a role in setting up a Matthew Effect. The only part in which luck is only partial is in being enthusiastic on a subject, the time and effort spent to gain expertise on it (base level of intelligence luck determined, 1 sigma sufficient) and the obsession to be able to think all the time on a subject.
If you are interested in this sort of thing I strongly suggest anything by Simonton (as an aside one of his papers argues that it is not what age you start that matters but how many years into your career that determines the drop off, so late starters get the same burst and drop just shifted in time).
[1] http://www.garfield.library.upenn.edu/essays/v4p660y1979-80....
[2] A small group of highly productive individuals is most likely to participate in multiples, including independent rediscoveries. These same persons are also unusually intimate with the "technoscientific" zeitgeist and perhaps equally gifted with an inordinate amount of good luck.
Not free: http://www.deepdyve.com/lp/psycarticles-reg/multiple-discove...