The Location: This research was conducted at the Jacksonville Zoo and Gardens in Florida. The bonobo group that resides there had no previous experience with musical tools or interactive participation in music or rhythmic studies.
The Setup: The experiments were conducted in the primate night house. A drum was custom designed for the bonobos by Remo Drum Company. The drum was fixed to the concrete floor of a small research space interconnecting larger play areas, allowing the bonobos free flow into and out of the area.
Our research approach relied on bonobo self-selection for focused interaction with a drum and a human drummer. To accommodate innate bonobo shyness, the research design featured multiple encounters with the same female human drummer, continuity of research personnel, and ongoing continual access for the bonobos to the drum and its space beyond the research sessions. Kuni, a female bonobo who had recently given birth, chose to play the drum most often.
The Method: The experimenter and a staff member were seated in the main walkway, separated from Kuni by a steel mesh door. Kuni’s daughter, Kenge, was almost always present while Kuni played the drum. At least one other bonobo was usually also present. A metronome sound was produced by the recording software, and delivered to the experimenter over headphones so that it would be inaudible to Kuni. The experimenter drummed in synchrony with the metronome at one of six predefined tempos. The staff member and the experimenter encouraged drumming verbally and by pointing to the drum. Kuni received a food reward and verbal praise for any episode of drumming.
Experiment 1 – Spontaneous Tempo & Tempo Matching: When Kuni began to strike the drum, the experimenter stopped and let her continue on her own. When Kuni stopped drumming, the experimenter began again. Kuni received a food reward and verbal praise for each and every episode of drumming. Six trials were recorded each day. We separated tempo matched and non-tempo matched episodes using statistical tests. Kuni’s spontaneous tempo was measured at 270 bpm, but she also matched tempo with the experimenter on many episodes. The video above includes sections of different trials at different tempos in which Kuni tended to match tempo.
Experiment 2 – Synchronization: Similarly to the tempo experiment above, the experimenter struck her drum in synchrony with a metronome at one of six predefined tempos. Unlike the first experiment, when the bonobo began to strike the drum, the experimenter continued drumming so that Kuni drummed simultaneously with the experimenter and synchronization could be assessed. The tempo of the trial above was 280 bpm. Drum strikes were recorded through microphones mounted inside each drum, using Logic Express software. The video includes the entire trial (longer periods of time during which the experimenter drummed – but Kuni did not – have been edited out). Kuni’s synchronization, assessed over the length of the entire trial, was statistically significant.
Reference: Large, E. W. & Gray, P. (2015). Spontaneous tempo and entrainment in a bonobo (Pan paniscus). Journal of Comparative Psychology, 129 (4), 317-28.