The perception of tempo in music.
Tempo is one factor that is frequently associated with the expressive nature of a piece of music. Composers often indicate the tempo of a piece of music through the use of numerical markings (beats min(-1)) and subjective terms (adagio, allegro). Three studies were conducted to assess whether listeners were able to make consistent judgments about tempo that varied from piece to piece. Listeners heard short extracts of Scottish music played at a range of tempi and were asked to make a two-alternative forced choice of "too fast" or "too slow" for each extract. The responses for each study were plotted as proportion of too fast responses as a function of tempo for each piece, and cumulative normal curves were fitted to each data set. The point where these curves cross 0.5 is the tempo at which the music sounds right to the listeners, referred to as the optimal tempo. The results from each study show that listeners are capable of making consistent tempo judgments and that the optimal tempo varies across extracts. The results also revealed that rhythm plays a role, but not the only role in making temporal judgments.