A method for testing synchronization to a musical beat in domestic horses (Equus ferus caballus)

According to the “vocal learning and rhythmic synchronization hypothesis” (Patel, 2006), only species capable of complex vocal learning, such as humans and parrots, have the capacity to synchronize their movements to a musical beat.  While empirical research to date on a few species (e.g., parrots and monkeys) has supported this hypothesis, many species remain to be examined. Domestic horses are particularly important to study, as they are vocal non-learners who are occasionally reported to move in synchrony with a musical beat, based on informal observations. If these reports are substantiated by scientific experiments, this would refute the vocal learning hypothesis and provide a new species for the comparative study of musical rhythm.  Here we present a new method for testing whether horses can synchronize their trotting to a musical beat, including an illustration of data analysis based on data collected from one horse.