Passing up "show horse" senators who can hear a reporter's notebook open from across the Capitol, the big news media allot most of their space and air time to those with seniority and leadership positions, Stephen Hess of the Brookings Institution says in his latest study of the news media.

"Neither good looks nor clever views can compete with the aphrodisia of a leadership position," Hess concludes in his analysis, "The Ultimate Insiders: U.S. Senators in the National Media."

"So long as the Senate lives by seniority, Senator Blowdried will never be able to compete with Senator Mandarin for sustained attention on the network evening news or in large-circulation newspapers."

In 1981-82, for example, then-majority leader Howard H. Baker Jr. (R-Tenn.) was mentioned 360 times on network evening news programs, compared to 197 for Sen. Edward M. Kennedy (D-Mass.), 113 for Minority Leader Robert C. Byrd, and once each for Spark M. Matsunaga (D-Hawaii) and Quentin N. Burdick (D-N.D.)

Other ways to gain the national spotlight, according to Hess, are to become an expert on one issue -- as Sam C. Ervin Jr. (D-N.C.) did on Watergate -- to be on the right committee or to hold a party position.

A better method is to run for president, or to hint at running. In 1983, Hess found, four of the top 10 scorers for news coverage were running for the Democratic nomination. The 10 were John Glenn (D-Ohio), Alan Cranston (D-Calif.), Baker, Robert J. Dole (R-Kan.), Gary Hart (D-Colo.), Ernest F. Hollings (D-S.C.), Kennedy, Jesse Helms (R-N.C.), Pete V. Domenici (R-N.M.) and Daniel Patrick Moynihan (D-N.Y.).

Hess, who spent much time in the Senate press gallery, also reports on other qualities that play to the press. He found, for instance, that reporters often are attracted to senators who return calls promptly and who say something interesting or unpredictable.

He said senators who most repel reporters fall into "two unequal categories. Those in the lesser group are usually described as boy scouts: there is a cooky-cutter sameness to their values and sometimes even to their appearance."

Far worse is pomposity, which Hess describes as "the deadliest sin" from the news media perspective. He quotes Dorothy Collin of The Chicago Tribune as espousing the theory that young senators start pompous, mellow in middle age and return to pomposity in old age.

Hess also said reporters seldom describe senators as handsome, even though he concluded -- on watching from the gallery -- that most senators were good-looking, at least 20 could pose for Arrow shirt ads and one "bears a resemblance to Robert Redford." Hess identified the latter as Dan Quayle (R-Ind.)