Back when I was majoring in History in college, one professor explained to the class that when a person made multiple statements about a time or event they lived through or were involved with, and they contradicted each other, it was generally best to give more weight to the earlier statements. The reasoning was primarily that the person's memory would be fresher and the actual course of events would tend to be more clear in their mind. Additionally, earlier comments would be less likely to be colored by long term reactions to the events (example: a politician who had been vocally pro-segregationist in the 1950s but then says in the 1990s that he never really liked the idea of segregation).
Since that time I have come across this principle stated in histories that I have read. Invariably when I see it, I am reading a very well-sourced history with solid analysis (most recently Playing at the World by Jon Peterson).
My question is this: is there a commonly used or accepted term for this historical principle?
Note that opinions on the validity or usefulness of the principle are not the subject of my question. Thank you.