The Perception of Time in Music

Abstract

This thesis is concerned with the perception of time in music with emphasis on tempo, emotion and time perception in music. Three studies were conducted to assess whether listeners were able to make consistent judgements 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 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 judgements 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 judgements. In the previous studies, it is possible that listeners might be using an average tempo from previously heard extracts to make every subsequent response. We wanted to assess this by presenting a single stimulus per participant and therefore remove any effects of the context on participant's responses. Using this technique we shall show that listeners can make 'too fast' and 'too slow' responses that are independent of previously heard extracts. In addition the data reveal similar results to those found in the first experimental chapter. The 3rd chapter deals with the effect of changes in the tempo of music on the perception of happy and sadness. Listeners heard short extracts of music that varied in tempo and were asked to make a 2AFC of happy or sad for each extract. Separate psychometric functions were obtained for each extract of music, and the points where these crossed 83% and 17% happy were calculated, and treated as happy tempo and sad tempo respectively. The results show that most extracts can be perceived as both happy and sad just by varying the tempo. However, the tempo at which extracts become happy or sad varies widely from extract to extract. We show that the sad and happy tempi are related to the size of the intervals (pitch changes) in the extract. In considering what might be involved in the perception of time in music we wanted to assess what effect small changes to a stimulus would have on perceived duration. We presented 2 auditory stimuli and show that the perceived duration of the test stimulus with a change in pitch increased as the size of the pitch change increased. The results are explained in terms of event strength where strong events cause perceived duration to increase whilst weak events are perceived to be shorter by comparison.