This episode's headline: Artificial Intelligence. The guests include RANDALL DAVIS, Massachusetts Institute of Technology; ROGER SCHANK, Yale University. Byline: In New York: ROBERT MacNEIL, Executive Editor; In Washington: JIM LEHRER, Associate Editor; KENNETH WITTY, Producer; MAURA LERNER, Reporter; Videotape Section: NORMAN LLOYD, Camera; OTTO KENNEDY, Sound; JUAN BARNETT, Editor