YOU DON’T NEED an advanced degree in psychology to see that America’s consumer society, in an age of iPods, Blackberries and instant messaging, is gripped by a collective attention deficit disorder.How have Hollywood’s most famous directors responded to this predicament? By releasing longer and longer movies. Ridley Scott has just delivered the director’s cut of “Kingdom of Heaven.” He’s added 45 minutes, bringing the length of his lugubrious medieval epic to 190 minutes. Peter Jackson’s “King Kong” is, for at least 100 of its 187 minutes, wildly entertaining. But he hasn’t done Universal any favors by delivering a final cut so long you might assume he was paid by the frame. At that length, “Kong” is struggling to keep pace at the box office with “The Chronicles of Narnia: The Lion, the Witch and the Wardrobe,” which comes in at a comparatively modest 139 minutes. “Narnia” is enjoying an additional showtime a day at most theaters, an advantage that one exhibitor told me was making a huge difference at his megaplexes. One can’t draw a direct line between a film’s running time and its commercial performance. But consider the many examples of long-winded movies that came up short at the box office this year: “Cinderella Man,” 144 minutes, “The Island,” 138 minutes, “In Her Shoes,” 140 minutes (the same length as “Batman Begins,” minus the pyrotechnics). Oddly enough, Scott acknowledged, in an interview with a blogger before “Kingdom of Heaven” was released, that the 145-minute version was the optimal theatrical experience. “Do you think operas tend to be a bit long?” he asked. “Do you think theater tends to be a bit long? You think, ‘Oh my God, there’s going to be another act.’ ” Uh… yeah. THE TREND IN ADVERTISING, it’s worth noting, is toward the opposite extreme. Wary of the commercial-zapping tendencies of their target audience, sponsors are slicing their network spots into smaller and smaller segments. Most networks now offer 15-second spots to advertisers. In an unusual move, first reported in the Wall Street Journal, AOL bought 35 seconds on Fox’s “Prison Break” last month and carved the segment into two ads, one 30-seconds in length, and one just five. A Fox spokesperson told me that as a policy, the network doesn’t sell five-second ads. But the general drift of the ad business is clear enough: As traditional formats fail to hold the attention of hyperactive consumers, commercial formats are growing much more flexible. Hollywood studios, too, are subdividing ads and trailers into shorter formats, as a higher percentage of marketing budgets are diverted from network TV to Internet ads and handheld devices. The trendiest new platform for such ads: the video iPod. In November, Apple Computers honcho Steve Jobs announced that 125,000 Pixar shorts were purchased from iTunes in the past month. One trend to watch in 2006: more movie ads and snippets of footage delivered to consumers in the MP4 format used by video iPods. FINAL-CUT DIRECTORS can’t be expected to pander to A.D.D.-afflicted consumers, nor should they. Indeed, there’s nothing wrong in principle with a movie that runs for hours. “Harry Potter” was a safe bet at 157 minutes. And as Daily Variety’s review points out, “Syriana,” at 128 minutes, might have been a bit more coherent if it were longer. One of the finest theatrical releases of the year was Marco Tullio Giordana’s “Best of Youth” (it “doesn’t have a boring millisecond,” raved Slate.com). Originally a miniseries for Italian TV, “Best of Youth” clocked in at 400 minutes. But it also played in about five theaters. Films like “Munich” and “The New World” hope to reach a far broader audience than that. But at 164 and 149 minutes, respectively, they may face an uphill battle. Add the travel time to get to the theater, lines to park and buy popcorn, and 20 minutes of commercials and trailers, and you’re looking at a five-hour investment. Is it any surprise so many people would just as soon wait a few months for the DVD?