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Emotionality and intentionality in bonobo playful communication

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Abstract

Great apes show very complex systems for communicating emotions and intentions. Whereas gestures are intentional signals, facial expressions can disclose both emotions and intentions. The playful context is a good field to explore the possible dichotomy between intentionally and emotionally driven signals as it has been suggested that one of its functions is to learn producing and decoding communicative patterns. To understand how signals are produced during play and how they are modified in the course of ontogeny, we investigated the use of playful facial expressions and gestures in bonobos (Pan paniscus), a tolerant species showing a high propensity to play even as adults. Our results showed that the use of play faces and gestures is strongly influenced by the characteristics of the play session. Both play faces and gestures were more often performed when social play involved physical contact and when the receiver was visually attending, thus suggesting that both signals can be strategically employed when communicating becomes more urgent. Compared to play faces, gestures were more frequent during dyadic than polyadic sessions, when a unique receiver was involved. Being gestures not context specific, they are probably used more selectively by the sender. On the contrary, play faces are context specific and transmit an unequivocal positive message that cannot be misconceived. These features legitimize a broad use of playful facial expressions, independently of the number of playmates. The similarities and differences in the production of these signals are probably linked to the different degree of emotionality and intentionality characterizing them.

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Acknowledgments

We thank the Apenheul Primate Park (Apeldoorn, The Netherlands), General Curator Frank Rietkerk, and the bonobo keepers for allowing and facilitating this work. We also thank Francesca Coppola for her assistance. We thank Walter Rapitalà and Roscoe Stanyon for their important clarifying input to the discussion and critical revision of the manuscript. This research was supported exclusively by private funding. This research complies with current laws of the Netherlands and Italy.

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Authors and Affiliations

  1. Dipartimento di Bioscienze, Università di Parma, Parma, Italy

    Elisa Demuru

  2. Centro Ateneo Museo di Storia Naturale, Calci, Università di Pisa, Pisa, Italy

    Elisa Demuru & Elisabetta Palagi

  3. Dipartimento di Neuroscienze, Università di Parma, Parma, Italy

    Pier F. Ferrari

  4. Unità di Primatologia Cognitiva, Istituto di Scienze e Tecnologie della Cognizione, Consiglio Nazionale delle Ricerche, Rome, Italy

    Elisabetta Palagi

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  1. Elisa Demuru
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Correspondence to Elisa Demuru.

Electronic supplementary material

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10071_2014_804_MOESM1_ESM.jpg

Play Face (male subject on the left) and Full Play Face (female subject on the right) shown by two adult bonobos during a face-to-face interaction while playing in contact. (JPEG 1670 kb)

10071_2014_804_MOESM2_ESM.jpg

An immature female (on the right) is performing a Play Face and a Beg With Hand gesture during a playful contact with an adult male (on the left) (for the description of the gestural item see Pollick and de Waal 2007) (JPEG 895 kb)

10071_2014_804_MOESM3_ESM.jpg

An immature female puts her finger into the mouth of an adult male (for the description of the gestural item see Pollick and de Waal 2007). (JPEG 175 kb)

Supplementary material 4 (DOCX 17 kb)

Playful invitation of an adult male towards a newborn. The adult male, after engaging the gaze of the newborn, performs a Full Play Face and slightly shakes its head in front of him. Then, the adult male engages in self-handicapping behaviours (putting on its own back). (AVI 10728 kb)

An adult male performs a Flap and Reach Out Up gestures to invite to play an infant male, who responds to the invitation (for the description of the gestural item see Pollick and de Waal 2007) (MPG 8343 kb)

An adult male manage a polyadic playful interaction with two immatures, a male and a female. At the very beginning of the video, the juvenile female (on the right) performs a Full Play Face (AVI 10010 kb)

Immediately after the interruption of a contact play session two subjects, an adult male (ADm) and an immature female (IMf) engage in a facial expression and gestural “dialogue”. IMf: pout face, silent bared-teeth (Pollick and de Waal 2007); ADm: Head Nod (Hobaiter and Byrne 2011a); IMf: Reach Out Up (Pollick and de Waal 2007) (AVI 13200 kb)

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Demuru, E., Ferrari, P.F. & Palagi, E. Emotionality and intentionality in bonobo playful communication. Anim Cogn 18, 333–344 (2015). https://doi.org/10.1007/s10071-014-0804-6

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