Sherlock/Spock
I am not certain of when I learned that information, but I imagine that it was during my early studies of xenobiology. Early education on Vulcan is extremely thorough. And our capacity to retain information is much greater than that of most humans. Which isn't to say that Vulcans are more intelligent, but that we are able to create, store and access episodic and semantic memories more easily and for greater lengths of time than humans.