At ABC, CBS and NBC News, Accentuating the Differences There was a time when each of the Big Three nightly newscasts on American television tended to open with the same story - the latest campaign speech, a new government study or perhaps a big snowstorm. That time is gone. Influenced by cable and the Internet, the nightly newscasts are shaking up conventions that stretch back 50 years, seeking to distinguish themselves by picking different stories and placing them in different orders. On any given night, one might lead with the Republican campaign, another with extreme weather and the third with an exclusive interview. "The three evening newscasts have become more different from one another than at any time I can remember," said Bill Wheatley, who worked at NBC News for 30 years and now teaches at Columbia. The differences provide a stark illustration of the state of the news media - much more fragmented than ever, but also arguably more creative. Viewers these days "make their own choices," said Ben Sherwood, the president of ABC News. They pick what matters most to them, and we are trying to be adaptive and responsive to those sweeping changes. In the mornings, too, the networks are highlighting their differences. On Monday, CBS, which has been stuck in last place for decades, will introduce a new morning show featuring Charlie Rose that promises more hard news than NBC and ABC and no cooking segments or couch chitchat. Steve Capus of NBC, the longest-serving of the three current network news chiefs, called the "different tacks" taken by the networks in the last year a positive development. "What is going to rule the day, in this age, is unique content," he said. On some days, the differences at 6:30 p.m. are substantive; on a Thursday in December, CBS led with Iran's capture of a United States drone surveillance aircraft, NBC opened with an investigation into the mishandling of soldiers" remains, and ABC with the mysterious shooting of a police officer at Virginia Tech. On other days, they are stylistic; on Tuesday, as the Iowa caucus commenced, ABC led with a piece on Rick Santorum's surge, CBS led with a news-making interview of Newt Gingrich, and NBC with a recap of the day's campaigning. There are differences in tone, as well. Scott Pelley of CBS evokes anchors of yesteryear while ABC's Diane Sawyer radiates empathy for her subjects. These are "eye of the beholder" factors, as Brian Williams of NBC put it. "We are different people," he said, "so naturally we all bring a different "voice" to our on-air writing and our delivery style." The main public TV nightly newscast, "PBS NewsHour," also differs from the three commercial newscasts; it tends to have more coverage about government and international events and much less about crime and disasters, according to the Project for Excellence in Journalism, an arm of the Pew Research Center that studies the nation's news output. For decades, there were only "marginal differences" among NBC, ABC and CBS, said Tom Rosenstiel, who directs the project. When one tried something new that viewers apparently liked, the others would assimilate it. Now, instead, they are counterprogramming. The biggest changes are apparent on CBS and ABC, which have long trailed NBC in the news ratings. ABC's new push to humanize the news and CBS's heavily promoted emphasis on hard news may make NBC News the Goldilocks news division - not too hot, not too cold, just right. Then again, some people have different tastes. "I think it's a great sign of the times that everybody's not in lockstep on the first story every night," Ms. Sawyer said. Her staff members, she said, start each day by discussing "the questions that we think people at home are going to be asking." Some staff members at ABC's competitors privately criticize "World News" for bending too far toward human interest stories; on Wednesday, for instance, the broadcast talked about the tax code by highlighting a California union's ad that compares the millionaire Kim Kardashian's tax bill to that of a middle-class Californian. Is that hard news or soft? ABC would say that question is outdated.