The way I see it, each generation of F1 drivers tended to included one or two let´s call it hard drivers. TV coverage in the early years was non-existant or poor, not covering all the track. This makes it difficult for us today to understand if and when those harder drivers actually played dirty. However, I do not recall many incidents that have been considered questionable by the contemporaries, appart from the few examples already mentioned in this thread.
However, in the 80's TV coverage was already good enough for us viewers to be able to get a much clearer picture of each driver's style. My impression of Senna at the time was that he had no problem using dirty tricks whenever he felt necessary. This was confirmed when Senna himself publicly admitted his infamous move on Prost in Suzuka had been intentional. This was the first time ever a driver assumed that his title had been achieved by dirty means. Surprisingly, Senna was not punished by FIA, and was not retroactively stripped out of his 1990 title, one thing I still cannot understand.
Senna did not invent dirty driving. But the fact that he managed to get away with a dirty title undoubtedly generated a sense of impunity. Schumacher realized this and built a tremendously successful career which happily includes some of F1 lowest moments.
I do not think current drivers still have this type of approach. Also because modern F1 has this punishing obsession that questions the most simple driving incident and, subsequently, does not leave much space for real old style dirty driving. I think today's F1 drivers have a different sense of impunity. They know that F1 has become a very safe sport and that they are not risking their lives like the drivers of the past. They can afford making these so called defensive manœuvres which would had been considered dangerous dirty driving in the past but that nowadays are not more than stupid unsporting attitudes with no expected dangerous consequences.
