Twelve Americans, including Utah philanthropist Obert C. Tanner, were named Thursday as winners of the National Medal of Arts for their contributions to the cultural life of the United States.

The medals will be presented by President and Mrs. Reagan at a White House luncheon on Aug. 9. It will be the fourth time the medals have been awarded. They were created by Congress in 1984.Winners are:

- Tanner, 84, born in Farmington, Utah, professor emeritus of philosophy at the University of Utah and a philanthropist who has supported literary and other arts projects from a fortune amassed in his industrial diamond and jewelry businesses.

- Actress Helen Hayes, 87, born in Washington, who first appeared on stage at the age of 5, made her New York debut in 1909 and has played in works of Shakespeare, Tennessee Williams and Eugene O'Neill during her long career.

- Photographer, author, filmmaker and composer Gordon Parks, 76, born in Fort Scott, Kan., who was on the photographic staff of Life Magazine for 19 years before branching out into other activities.

- Dancer, choreographer and dance director Jerome Robbins, 69, born in New York, who choreographed such Broadway hits as "On the Town" and "Call Me Madam."

- Composer and conductor Virgil Thomson, 91, whose works include the operas "Four Saints in Three Acts" and "The Mother of Us All," written with Gertrude Stein.

- Art historian and teacher Sydney J. Freedberg, 74, born in Boston, a noted scholar of the Italian Renaissance who taught at Harvard from 1938 to 1983 with the exception of eight years at Wellesley College.

- Roger L. Stevens, 78, chairman of the board of trustees of the John F. Kennedy Center for the Performing Arts from 1961 until 1988, who also served as a special presidential assistant on the arts in the Johnson administration.

- Art patron Brooke Astor (Mrs. Vincent Astor), born in Portsmouth, N.H., president of The Vincent Astor Foundation, which has provided more than $64.6 million for arts projects.

Winners who were born outside of the United States are:

- Novelist Saul Bellow, 73, born in Lachine, Canada, and raised in Chicago, whose writings have won him the Nobel Prize for Literature, the Pulitzer Prize, and three National Book Awards.

- Architect I. M. Pei, 71, born in China, designer of the East Building of the National Gallery of Art in Washington and the John F. Kennedy Library in Boston.

- Pianist Rudolf Serkin, 85, born in Bohemia, now part of Czechoslovakia, a one-time child prodigy who made his U.S. debut in 1933 and is noted for his performances of the Viennese classics.

- Music patron Francis Goelet, 62, born in Bordeaux, France, who has commissioned new works for the New York Philharmonic and donated money for new productions of the Metropolitan Opera.