Reports of equitonic scale systems in African musical traditions and their implications for cognitive models of pitch organization

Abstract

Psychological research into musical behavior has mostly focused on Western music, explored with experiments utilizing Western participants. This ethnocentric bias limits the generalizability of many claims in the field. We argue that our current understanding of the cognition of pitch organization might be helpfully informed by data gathered in non-Western contexts. In particular, musical traditions featuring equal-spaced scales (where all scale-step interval sizes are equal) are suggested to pose a challenge to popular models of pitch organization, in which unequally spaced scales are suggested to provide cognitive anchor points for on-the-fly pitch orientation. This article presents a summary and theoretical consideration of all available evidence on equal-spaced scales, the vast majority of which appear in east Africa. It is noted that despite equal spacing, there is evidence to suggest that tonal centers are still perceived by idiomatic listeners. We then proceed to propose how such tonal center perception is possible within equal-spaced tonal environments. In short, the existence of equal-spaced scale systems shifts the focus of research from interval uniqueness to alternative explanations for the perception of tonal centers, such as implicit statistical tracking, secondary parameters, recognition of learnt patterns as tonal cues, and so on. Throughout, we note that interdisciplinary work involving ethnomusicologists and psychologists would be beneficial in answering questions about music cognition, and by extension, human cognition in general.

Convergent evolution in a large cross-cultural database of musical scales

“…Out of all the scales we found, most can be thought of as variations on the 5-and 7-note equidistant scales. This is at odds with some recent literature that claims that equidistant scales are rare [5,9,[102][103][104], which seem to be aided by some hypothesised benefits of unequal step sizes [105,106]. It seems that equidistant scales can only be considered rare if you are extremely conservative about what level of precision must be reached to be called equidistant.…”

Pitch Syntax as an Evolutionary Prelingual Innovation

“…Pitch, or tonal, hierarchy, the basis for the syntactical ordering of pitches in tonal music 2 (Krumhansl, 1990), makes the use of pitch in music unique. Although the musical scales used in different cultures vary in terms of their intervals, even in cultures that use scales in which pitches are equidistant from each other, individual pitches are experienced in relation to one (Ross & Knight, 2019) or more pitch centers (cf. Ambrazevičius & Wiśniewska, 2009) that underpin the organization of every pitch hierarchy.…”

Cross-cultural data shows musical scales evolved to maximise imperfect fifths

“…Equidistant scales are typically considered rare (44), and non-equidistant scales are professed to have advantages over equidistant scales (2,(45)(46)(47). However many scales are almost equidistant (48)(49)(50)(51), and given the few ways to construct an equidistant scale to assign harmonicity scores to intervals. The highest scoring intervals (frequency ratios are shown for the top five) act as windows of attraction, whereby any interval in this window is assigned its score.…”

“…Equidistant scales are typically considered rare (44), and non-equidistant scales are professed to have advantages over equidistant scales (2,(45)(46)(47). However many scales are almost equidistant (48)(49)(50)(51), and given the few ways to construct an equidistant scale the base probability is low. Nonetheless, the majority of scales are non-equidistant, so this theory is clearly incomplete.…”