Monkeys have rhythm

Abstract

Synchronizing movements to music is one of the hallmarks of human culture whose evolutionary and neurobiological origins remain unknown. The ability to synchronize movements requires 1) detecting a steady rhythmic pulse, or beat, out of a stream of complex sounds, 2) projecting this rhythmic pattern forward in time to predict future input, and 3) timing motor commands in anticipation of predicted future beats. Here, we demonstrate that the macaque is capable of synchronizing taps to a subjective beat in real music, and even spontaneously chooses to do so over alternative strategies. This contradicts the influential "vocal learning hypothesis" that musical beat synchronization is only possible in species with complex vocalizations such as humans and some songbirds. We propose an alternative view of musical beat perception and synchronization ability as a continuum onto which a wider range of species can be mapped depending on their ability to perform and coordinate the general abilities listed above through association with reward.