Asymmetric Cognitive Clock Structures in West African Rhythms

Results of an experimental investigation of pattern production by a West African (Asante) master drummer are reported. He performed bimanual tapping, with the Kete time-line pattern in one hand and either a regular 3-pulse or a regular 4-pulse in the other hand. Experimental variables manipulated were pulse-stream size (three or four), pulse hand allocation (left or right), and recording protocol, which was either synchronous (played in relation to a computer-generated tone) or spontaneous (no tone). Structural equation modeling was used to systematically examine the comparative fit of two mental models: an asymmetric timeline- ground (TLG) model, which represents a computational elaboration of traditional African understanding, and a pulse-ground (PG) model, which is based on Western ideas of regular meter. The African-based TLG model with at most minor adjustment provided an excellent fit for seven of eight experimental conditions; one condition achieved a good fit only after more substantial modification of the model. The African TLG model achieved superiority over the Western PG model only under certain specific conditions, suggesting that the use of the African cognitive model is subtle, context-dependent, and linked to specific training regimes.