In Close Encounters of the Third Kind a musical motif takes on a pivotal role in the plot. The whole film is based around a simple five note motif which functions as a code, heralding the interaction between humans and the aliens.
The transformations of this motif, contribute significantly to the story line. For instance, when the humans attempt to make contact with the aliens, it goes through a number of variations. These include changing the register, placing some of the notes in different octaves, and varying the tone colour through instrumentation.
Steven Spielberg describes the music as being like an additional character in the movie. The five note theme used in Close Encounters functions as a form of communication in the film. The aliens communicate though lights, colours and notes.
motif is a signal that takes on the role of a greeting. The composer,
John Williams went through hundreds of permutations of five notes to
come up with the final combination of notes.
To get the spaceships' attention prior to their arrival at Devil's Tower, the five notes the scientists play are G, A, F, (octave lower) F, C. When they arrive at the tower and are attempting communication, the notes they play are B flat, C, A flat, (octave lower) A flat, E flat.
In the sky above them, streaking objects resembling comets whoosh through the blackness. Roy whispers expectantly to Jillian: "We're the only ones who know. The only ones." Three tiny, neon-lit scout ships appear with the tiny red orb following in their wake - they hover over the end of the runway. Audio analysis personnel ready themselves to communicate with the sparkling, illuminated objects at the rendezvous point. A giant electronic board covered with colored strips and a powerful synthesized musical keyboard have been constructed at the site. The Air Force scientists duplicate the electronic sounds that they have heard in transmissions, mixing them with light sequences (on colored strips) to communicate. The computer and audio specialists play the loud clear sounds of the five-note sequence after the signal: "Sunset":
Start with the tone. (Pinkish-red) - G Up a full tone. (Orange) - A Down a major third. (Purple) - F Now drop an octave. (Yellow) - F (an octave lower) Up a perfect fifth. (White) - C
[Best Animated Feature Oscar-winner Happy Feet (2006) directly referenced this scene in which the penguin population communicated with "aliens" (humans) by dance steps exchanged between the two, after the human's "space ship" (a helicopter) arrived and perched on a Devils Tower-type outcropping.]
French scientist Lacombe suggests that the organist play the sequence with an increased tempo and try different frequencies for the five notes or tones, to lure the friendly mothership to land, as he marches out to the end of the runway. The three ships dance above the runway and respond with their own duplicate tones - they emit the musical sounds in the specific combination of five notes. And then they fly off, separating and soaring heavenward. Applause exuberantly erupts through the audience.