Surrealism was invented by a group of Spanish and French artists and writers and film-makers; or at least given that name by them. The general approach was a sort fairly systematic irrationality, with shocks. This was at the time of the 'Spanish Civil War'. That war was very brutal and cruel, but the point here is that it was also impossible to get reliable information about it - for one thing, there was a Jewish element which naturally was censored completely at the time. Other aspects included secret funding, secret backing by the British, and so on. Just as with wars now - Iraq, Libya etc etc - lies dominate. The natural artistic reaction during the Spanish Civil War was (maybe) surrealism - for one thing, it avoided all consideration of the actualities of their present-day conflicts. In the same sort of way, during the First World War there were a few movements - vorticism, the 'Dadaists', which turned away from what was happening. BBC radio after WW2 had the 'Goon Show'. Bob Dylan (at the time of the Vietnam War), and, later, Monty Python of the BBC's state propaganda illustrate the same sort of thing.
And there's something analogous in science: in the late 19th century physics and mathematics seemed pretty much sewn up, so that the only progress seemed to be through frankly weird speculations. After 1945, there's been almost no space in science journals to wars - where are the accounts of birth defects in Vietnam caused by American chemical warfare, for example? They're even censored out of medical reference books. I think this sort of psychology helps explain attitudes to science fiction, the uncritical promotion of completely impractical ideas, the failures of 'intellectuals' generally to address important issues.
[Added March 2015: A related issue is evasion by intellectual timewasting. For example, the Times crossword, noted as a benchmark for complication, and including quotations from English literature (and Latin, Greek) and puns, anagrams, and general wordplay involving ambiguities and wordplay, was introduced in he 1920s. (An Aldous Huxley story has an anti-hero who liked simpler crosswords). During the Second World War, British scientists are reported to have wasted, or enjoyed, enormous numbers of man-hours on problems of coin weighing. This is obvious enough, of course. My reason for commenting was a look back at detective stories, and other books, by Michael Innes (Professor J I M Stewart) who was in his 30s during WW2. His stories have fantastical plots, though mostly based discreetly on money shortages, but always avoided forbidden thoughts.
Projecting back in time, and outwards geographically, we might expect similar movements, assuming some degree of freedom - RW]