Unidirectional adaptation in tempo in pairs of chimpanzees during simultaneous tapping movement: an examination under face-to-face setup

Abstract

Many studies have reported a spontaneous nature to synchronized movement in humans and in non-human primates. However, it is not yet clear whether individuals mutually adapt their movement to each other or whether one individual significantly changes to synchronize with the other. In the current study, we examined a directionality of the tempo adaptation to understand an introductive process of interactional synchrony in pairs of chimpanzees. Four pairs, consisting of five female chimpanzees, produced a finger-tapping movement under a face-to-face experimental setup where both auditory and visual cues of the partner's movement were available. Two test conditions were prepared: alone and paired. An analysis of the tapping tempo depending on condition showed that only one chimpanzee in each pair significantly changed their tapping tempo in the direction of the partner's tapping tempo in the paired condition compared with the alone condition. The current study demonstrated that unidirectional adaptation in tempo occurs in pairs of chimpanzees when they simultaneously produce the tapping movement under auditory and visual interaction.

Inter-individual coordination in walking chimpanzees

“…Particularly fastacting young chimpanzees in an individual finger-tapping task slowed down their actions when they had to coordinate actions with their slower mothers. 27 Adjusting the speed of actions provides further evidence that the chimpanzees adapt their behavior toward others when walking with them. In addition, when the chimpanzees walked together, the phase relationship values were shorter and showed less variation, suggesting more coordination, compared with when individuals were walking independently (Fisher's test: F = 222.79, df = 84, n = 23, p < 0.001; Figure 4).…”

Effect of visual cues in addition to moderate auditory cues on temporal coordination: A comparative study in humans and chimpanzees

“…In the first study conducted under the side-by-side setup, we demonstrated that one chimpanzee gradually matches her tapping movement with auditory cues which was from an interacting partner (Yu & Tomonaga, 2015). In the second study conducted under the face-to-face setup, we found a general tendency on temporal coordination in chimpanzees (Yu & Tomonaga, 2016). These findings indicate that auditory cues can solely facilitate an interaction between chimpanzees but additional visual cues do enhance the influence of an interacting partner's movement on production of one's own movement.…”

“…One pair was from kin-relationship, 34-year-old mother [Chloe](GAIN-ID C-0441) and her 14-year-old daughter [Cleo] (GAIN-ID C-0609). Both chimpanzees joined our previous experiments (Yu & Tomonaga, 2015;2016). Another chimpanzee pair was from non-kin relationship, 37-year-old female Pendensa [Pen] (GAIN-ID C-0095) and 38-year-old female [Mari] (GAIN-ID C-0274).…”

“…

Our previous studies reported that chimpanzees share an ability to produce spontaneous temporal coordination with humans (Yu & Tomonaga, 2015;2016). However, it remains unclear how visual cues of an interacting partner's movement influence on the emergence of tempo convergence.

…”

“…However, it remains unclear how visual cues of an interacting partner's movement influence on the emergence of tempo convergence. The current study conducted a comparative study in humans and chimpanzees under the same experimental setup as that used in Yu & Tomonaga (2016). Three conditions, including baseline, paired-invisible and paired-visible, were prepared.…”