The personalistic theory of scientific history is the idea that change/history/progress is attributable to the ideas of unique individuals (such as Einstein, Darwin, Hitler, or Napolean). It requires these special people for these advancements to take place.
The naturalistic theory is the idea that change/history/progress is a result of the intellectual and cultural climate of the times (such as how Galileo's discoveries and other heliocentric evidences were not accepted by society, or how evolution is still often not accepted today). If society doesn't want to accept a scientific truth, evidence is irrelevant.

Which do you think is more influential? Does it all fall into a single category, or is it a mix of both?

And what do you think about the influences of the naturalistic theory in censoring scientific progress? What do you think about the necessity of personalistic theory in scientific progress?