Discrimination of Temporal Regularity in Rats (Rattus norvegicus) and Humans (Homo sapiens)

The perception of temporal regularities is essential to synchronize to music and dance. Here, we explore the detection of isochrony in two mammal species. We trained rats (Rattus norvegicus) and humans (Homo sapiens) to discriminate sound sequences with regular intervals from sound sequences with irregular intervals using a go/no-go paradigm. We used four different tempi in the training sessions and two new tempi in the tests. We found that both rats and humans responded more to the novel regular test sequences than to the novel irregular test sequences. Differently from previous studies with birds, rats seem to have focused on the relative duration of the sounds, which means that they paid attention to global features defining the regularity of the sequences. In sum, this study suggests that detecting temporal regularities in sequences of sounds may have ancient evolutionary roots and could rely on timing mechanisms present in distantly related mammals.