Kurosawa was an obvious influence on Star Wars, but Psycho? From The Making of Star Wars (p266):
Hirsch did something similar as they were creating the temp track for Star Wars. "The scene where they pop out of the hatch in the Falcon, I laid in a very famous piece of Psycho music there," he says. "It was a three-note motif that Scorsese had insisted that Benny use in Taxi Driver. It was a dark, ominous three-note motif. Curiously enough, Johnny—I don't know if he did it deliberately or what—but it's now incorporated into his cue for that moment in the film. He's got the very same notes that appear in Psycho. they appear in Taxi Driver—and now they're in Star Wars.