Fourier analysis, a common technique in engineering, breaks down a complex wave form into its simple sine wave components. Communication researchers have recently suggested that this technique may provide an index of the rhythm of conversation, since vocalizing and pausing produce a complex wave form pattern of alternation between two speakers. To determine whether the suggestion has validity, Fourier analysis was used to characterize the rhythm of sound and silence in 2 markedly different sets of 24 conversations each. The first set ("low cognitive load" conversations) came from an earlier study in which previously unacquainted pairs spent 10 minutes talking about themselves. The second set ("high cognitive load" conversations) came from pairs of students asked to discuss a current events topic. Each subject was given 10 minutes to think about the issue before engaging in a 10 minute conversation with a same-sex partner. Voices of each subject were recorded and each conversation was converted into a curve by means of a microcomputer. Fourier analysis was able to group the flow of vocalizations and pauses into larger repetitive patterns and to distinguish between the two sets of conversations. There were more "megaturns," or slow moving cycles, indicating serious discussion, dominating the talking in the conversations dealing with the current events topic than in the getting-acquainted conversations. (FL)