Melodic contour does not cluster: Reconsidering contour typology

TL;DR

This study challenges traditional melodic contour typologies by demonstrating that phrase contours do not cluster into discrete types, advocating for a view of melodic contour as a continuous phenomenon.

Contribution

The paper introduces a new test for clustering in melodic contours and shows that contour shapes are better represented as continuous rather than discrete types.

Findings

No evidence of clustering in German, Chinese, or Gregorian chant contours.

Type frequencies in existing typologies may be unreliable.

Recent findings of four contour shapes may be artifacts of analysis.

Abstract

How to describe the shape of a melodic phrase? Scholars have often relied on typologies with a small set of contour types. We question their adequacy: we find no evidence that phrase contours cluster into discrete types, neither in German or Chinese folksongs, nor in Gregorian chant. The test for clustering we propose applies the dist-dip test of multimodality after a UMAP dimensionality reduction. The test correctly identifies clustering in a synthetic dataset, but not in actual phrase contours. These results raise problems for discrete typologies. In particular, type frequencies may be unreliable, as we see with Huron's typology. We also show how a recent finding of four contour shapes may be an artefact of the analysis. Our findings suggest that melodic contour is best seen as a continuous phenomenon.