Temporal adjustment of short calls according to a partner during vocal turn-taking in Japanese macaques

Abstract

Turn-taking is a common feature in human speech, and is also seen in the communication of other primate species. However, evidence of turn-taking in vocal exchanges within a short time frame is still scarce in nonhuman primates. This study investigated whether dynamic adjustment during turn-taking in short calls exists in Japanese macaques Macaca fuscata. We observed exchanges of short calls such as grunts, girneys, and short, low coos during social interactions in a free-ranging group of Japanese macaques. We found that the median gap between the turns of two callers was 250 ms. Call intervals varied among individuals, suggesting that call intervals were not fixed among individuals. Solo call intervals were shorter than call intervals interrupted by responses from partners (i.e., exchanges) and longer than those between the partner’s reply and the reply to that call, indicating that the monkeys did not just repeat calls at certain intervals irrespective of the social situation. The differences in call intervals during exchanged and solo call sequences were explained by the response interval of the partner, suggesting an adjustment of call timing according to the tempo of the partner’s call utterance. These findings suggest that monkeys display dynamic temporal adjustment in a short time window, which is comparable with turn-taking in human speech.

Interactive rhythms across species: the evolutionary biology of animal chorusing and turn‐taking

“…In fact, noncooperative coordination and competition often drive animal interactive displays . We illustrate these points by discussing and building upon some recent experiments and reviews of turn‐taking in nonhuman animals . Our intention, we stress, is not to criticize a related field or a particular paper.…”

“…These comparative efforts may offer valuable insights, but several issues need to be carefully monitored when investigating turn‐taking in nonhuman species. In particular, we argue that (1) turn‐taking may add a new (semantic and pragmatic) dimension to animal interactive communication, but in its temporal‐rhythmic dimension it is nonetheless only a part of the general collective activity known as chorusing; (2) some concepts from human turn‐taking are challenging to extend to all animals because they are still debated in (comparative) cognitive psychology, such as intentionality or cognitive flexibility/complexity: instead, attention‐like processes, such as salience filters and competitive selection, signal masking, and fixed time lags may suffice to explain much of animal interactive behavior; and (3) turn‐taking—if defined as signal alternations, in all their nuances (Table )—does not require cooperation in living species or in hominin history. In fact, noncooperative coordination and competition often drive animal interactive displays .…”

“…As shown in Figure , this term is increasingly employed in the literature and may soon overtake chorusing by number of publications. Among other aspects, research on turn‐taking investigates the rhythm and timing of human and, more recently, animal rhythmic interactions . Across species, definitions of, and assumptions underlying, turn‐taking strongly vary from simple call−response behavior to complex communicative patterns assuming “higher” cognition (Table ).…”

“…Among other aspects, research on turn-taking investigates the rhythm and timing of human and, more recently, animal rhythmic interactions. 9,13,[17][18][19][20] Across species, definitions of, and assumptions underlying, turn-taking strongly vary from simple call−response behavior to complex communicative patterns assuming "higher" cognition ( Table 1).…”

“…31 We illustrate these points by discussing and building upon some recent experiments and reviews of turn-taking in nonhuman animals. 9,13,18,19,21,23,24 Our intention, we stress, is not to criticize a related field or a particular paper. Instead, we wish to spawn a new approach for examining rhythm interaction across species, an approach that will incorporate ideas from linguistics and cognition, via turn-taking, and from work in animal rhythmic communication, via chorusing.…”