Proceedings of the Annual Meeting of the Cognitive Science Society

Groups of interacting individuals often coordinate in service ofabstract goals, such as the alignment of mental representationsin conversation, or the generation of new ideas in group brain-storming sessions. What are the mechanisms and dynamicsof abstract coordination? This study examines coordination ina sophisticated paragon domain: collaboratively improvisingjazz musicians. Remarkably, freely improvising jazz ensem-bles collectively produce coherent tonal structure (i.e. melodyand harmony) in real time performance without previously es-tablished harmonic forms. We investigate how tonal structureemerges out of interacting musicians, and how this structureis constrained by underlying patterns of coordination. Dyadsof professional jazz pianists were recorded improvising in twoconditions of interaction: a ‘coupled’ condition in which theycould mutually adapt to one another, and an ‘overdubbed’ con-dition which precluded mutual adaptation. Using a computa-tional model of musical tonality, we show that this manipu-lation effected the directed flow of tonal information amongstpianists, who could mutually adapt to one another’s notes incoupled trials, but not in overdubbed trials. Consequently,musicians were better able to harmonize with one another incoupled trials, and this ability increased throughout the courseof improvised performance. We present these results and dis-cuss their implications for music technology and joint actionresearch more generally.