I'm not sure overall-length would be affected by "short attention span" -- it would be "entertainment spikes" or I suppose "average time between significant eve

I'm not sure overall-length would be affected by "short attention span" -- it would be "entertainment spikes" or I suppose "average time between significant events". Perhaps the best term is pacing -- how fast does the story flow? You can keep someone with ADHD fully engaged with the same topic indefinitely, if you can keep the pacing fast enough to hold their attention. Video games and Casinos being the king of this. So you'd expect slower films/tv to fall out, and things to get faster and faster -- packing more in shorter timeslots, with less slowdowns for things like background, general discussion, landscape shots, etc. From that perspective, I'd say action flicks are definitely getting faster; bay's transformers being the king of it -- so quickly paced you can't even understand what the hell is going on; just the "feeling" of mechanical combat but it's really just a blur of sounds and machinery. Marvel too has basically dropped all pretense of a real "plot" -- it more a sequence of random flashy combat and big landscapes/weaponry/powers that suddenly ends with the credits. I'm not sure if however you could say intentionally slower genres like political dramas are getting faster by necessity of the masses' devolving minds; I don't watch enough of the newer ones to say. But even comparing something like West Wing to House of Cards, the latter is clearly more "packed".