I live in the USA, where people react poorly if you spoil a move or a book for them. However, the question What is the benefit in the Prologue "spoiling" the play in Romeo + Juliet? raises the interesting point that beliefs about spoilers vary according to location, time period, and culture.
Is it possible to trace our current aversion to spoilers to a specific time period? Have there been any works on the history of thought about spoilers?
I'm not quite sure how to ask this question successfully; please leave comments or edit if this question is too broad.