Scientists frequently explain their choice of field by referring to curves of interest and development, as in "peptide chemistry [is] tapering off ... but now ... this is the future, molecular biology, and I knew that this lab would move faster to this new area" - wikipedia 
Desire for credit appears to only be a secondary phenomenon; instead a kind of "credibility capital" seems to be the driving motive. In a case study, they show one scientist sequentially choosing a school, a field, a professor to study under, a specialty to get expertise in, and a research institution to work at, by maximizing and reinvesting this credibility (i.e. ability to do science), despite not having received much in the way of credit (e.g. awards, recognition).
Four examples: 1. X threatens to fire Ray if his assay fails, 1. A number of scientists flood into a field with theories after a successful experiment then leave when new evidence disproves their theories, 1. Y supports the results of "a big shot in his field" when others question them in order to receive invitations to meetings from the big shot where Y can meet new people, 1. K dismisses some of L's results on the grounds that "good people" won't believe them unless the level of noise is reduced (as opposed to K thinking them unreliable himself).
The credibility of a scientist and their results is largely seen as identical. "For a working scientist, the most vital question is not 'Did I repay my debt in the form of recognition because of the good paper he wrote?' but 'Is he reliable enough to be believed? Can I trust him/his claim? Is he going to provide me with hard facts?'"
CVs are the major way this credibility is proven and career trajectories are the story of its use. Technicians and minor leaguers, by contrast, do not accumulate capital but instead are paid a "salary" by major leaguers.
# See also