Easy Rider was one of the first films to make extensive use of previously released musical tracks, rather than a specially written film score. This is common with films now, but was quite unusual at the time (the exception being The Beatles films and some other special cases). Dennis Hopper and Peter Fonda did not write a full script for the movie and made most of it up as they went along. They didn't hire a crew, but instead picked-up hippies at communes across the country and used friends and passers-by to hold the cameras and were drunk and stoned most of the time. Fonda,  Hopper, and Jack Nicholson were actually smoking marijuana on camera. LSD, however, was not actually used during the acid scene, as Fonda has stated. During Jack Nicholson's "UFO" speech, Hopper was intent on getting him very stoned on marijuana. The laughing that eventually broke up his speech was not planned, and when Nicholson repeats the line "it . . . it . . . would be devastating . . . " it was the next take. However, Jack Nicholson was largely able to stick to the script as written, much to the crew's amazement. This is stark contrast to the other cast members, who improvised most of their lines.