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All Outputs (45)

Increased alertness and moderate ingroup cohesion in bonobos’ response to outgroup cues (2024)
Journal Article
Brooks, J., van Heijst, K., Epping, A., Lee, S. H., Niksarli, A., Pope, A., Clay, Z., Kret, M. E., Taglialatela, J., & Yamamoto, S. (in press). Increased alertness and moderate ingroup cohesion in bonobos’ response to outgroup cues. PLoS ONE, 19(8), Article e0307975. https://doi.org/10.1371/journal.pone.0307975

In a number of species, including humans, perceived outgroup threat can promote ingroup cohesion. However, the distribution and selection history of this association across species with varied intergroup relations remains unclear. Using a sample of 8... Read More about Increased alertness and moderate ingroup cohesion in bonobos’ response to outgroup cues.

Frans de Waal - A pioneer who shone a light on the primate mind. (2024)
Journal Article
Clay, Z. (2024). Frans de Waal - A pioneer who shone a light on the primate mind. Neuroscience & Biobehavioral Reviews, 162, Article 105725. https://doi.org/10.1016/j.neubiorev.2024.105725

Biology has just lost one of its greatest thinkers. An intellectual pioneer and exceptional observer of animals, de Waal inspired us all to think differently about animals as well as ourselves - his far-reaching impact within and beyond biology and p... Read More about Frans de Waal - A pioneer who shone a light on the primate mind..

The expression of empathy in human's closest relatives, bonobos and chimpanzees: current and future directions (2024)
Journal Article
Brooker, J. S., Webb, C. E., de Waal, F. B. M., & Clay, Z. (2024). The expression of empathy in human's closest relatives, bonobos and chimpanzees: current and future directions. Biological Reviews, 99(4), 1556-1575. https://doi.org/10.1111/brv.13080

Empathy is a complex, multi‐dimensional capacity that facilitates the sharing and understanding of others' emotions. As our closest living relatives, bonobos (Pan paniscus) and chimpanzees (P. troglodytes) provide an opportunity to explore the origin... Read More about The expression of empathy in human's closest relatives, bonobos and chimpanzees: current and future directions.

Perceptual integration of bodily and facial emotion cues in chimpanzees and humans (2024)
Journal Article
Heesen, R., Kim, Y., Kret, M. E., & Clay, Z. (2024). Perceptual integration of bodily and facial emotion cues in chimpanzees and humans. PNAS Nexus, 3(2), Article pgae012. https://doi.org/10.1093/pnasnexus/pgae012

For highly visual species like primates, facial and bodily emotion expressions play a crucial role in emotion perception. However, most research focuses on facial expressions, while the perception of bodily cues is still poorly understood. Using a no... Read More about Perceptual integration of bodily and facial emotion cues in chimpanzees and humans.

Group-specific expressions of co-feeding tolerance in bonobos and chimpanzees preclude dichotomous species generalizations (2023)
Journal Article
van Leeuwen, E. J., Staes, N., Brooker, J. S., Kordon, S., Nolte, S., Clay, Z., …Stevens, J. M. (2023). Group-specific expressions of co-feeding tolerance in bonobos and chimpanzees preclude dichotomous species generalizations. iScience, 26(12), Article 108528. https://doi.org/10.1016/j.isci.2023.108528


Bonobos are typically portrayed as more socially tolerant than chimpanzees, yet the current evidence supporting such a species-level categorization is equivocal. Here, we used validated group-level co-feeding assays to systematical... Read More about Group-specific expressions of co-feeding tolerance in bonobos and chimpanzees preclude dichotomous species generalizations.

Humans recognize affective cues in primate vocalizations: acoustic and phylogenetic perspectives (2023)
Journal Article
Debracque, C., Slocombe, K. E., Grandjean, D., Clay, Z., & Gruber, T. (2023). Humans recognize affective cues in primate vocalizations: acoustic and phylogenetic perspectives. Scientific Reports, 13(1), Article 10900. https://doi.org/10.1038/s41598-023-37558-3

Humans are adept at extracting affective information from vocalizations of humans and other animals. However, the extent to which human recognition of vocal affective cues of other species is due to cross-taxa similarities in acoustic parameters or t... Read More about Humans recognize affective cues in primate vocalizations: acoustic and phylogenetic perspectives.

Multimodal communication development in semiwild chimpanzees (2023)
Journal Article
Doherty, E., Davila-Ross, M., & Clay, Z. (2023). Multimodal communication development in semiwild chimpanzees. Animal Behaviour, 201(July), 175-190. https://doi.org/10.1016/j.anbehav.2023.03.020

Human language is characterized by the integration of multiple signal modalities, including speech, facial and gestural signals. While language likely has deep evolutionary roots that are shared with some of our closest living relatives, studies of g... Read More about Multimodal communication development in semiwild chimpanzees.

Between-group variation in production of pant-grunt vocalizations by wild bonobos (Pan paniscus) (2023)
Journal Article
Schamberg, I., Clay, Z., Townsend, S. W., & Surbeck, M. (2023). Between-group variation in production of pant-grunt vocalizations by wild bonobos (Pan paniscus). Behavioral Ecology and Sociobiology, 77(1), Article 14. https://doi.org/10.1007/s00265-022-03285-4

The potential for aggression is inherent in social interaction, and strategies to reduce the costs of aggression are ubiquitous among group-living animals. One strategy employed by lower-ranking individuals in a variety of species is the production o... Read More about Between-group variation in production of pant-grunt vocalizations by wild bonobos (Pan paniscus).

The Association Between the Bared-Teeth Display and Social Dominance in Captive Chimpanzees (Pan troglodytes) (2022)
Journal Article
Kim, Y., Vlaeyen, J., Heesen, R., Clay, Z., & Kret, M. (2022). The Association Between the Bared-Teeth Display and Social Dominance in Captive Chimpanzees (Pan troglodytes). Affective Science, 3(4), 749-760. https://doi.org/10.1007/s42761-022-00138-1

Humans use smiles — widely observed emotional expressions — in a variety of social situations, of which the meaning varies depending on social relationship and the context in which it is displayed. The homologue of the human smile in non-human primat... Read More about The Association Between the Bared-Teeth Display and Social Dominance in Captive Chimpanzees (Pan troglodytes).

Flexible signalling strategies by victims mediate post-conflict interactions in bonobos (2022)
Journal Article
Heesen, R., Austry, D., Upton, Z., & Clay, Z. (2022). Flexible signalling strategies by victims mediate post-conflict interactions in bonobos. Philosophical Transactions of the Royal Society B: Biological Sciences, 377(1860), https://doi.org/10.1098/rstb.2021.0310

Compared to other animals, humans supposedly excel at voluntarily controlling and strategically displaying emotional signals. Yet, new data shows that nonhuman great apes' emotion expressions may also be subject to voluntary control. A key context to... Read More about Flexible signalling strategies by victims mediate post-conflict interactions in bonobos.

Bared-teeth displays in bonobos (Pan paniscus): An assessment of the power asymmetry hypothesis (2022)
Journal Article
Vlaeyen, J. M., Heesen, R., Kret, M. E., Clay, Z., Bionda, T., & Kim, Y. (2022). Bared-teeth displays in bonobos (Pan paniscus): An assessment of the power asymmetry hypothesis. American Journal of Primatology, 84(9), Article e23419. https://doi.org/10.1002/ajp.23419

Facial expressions are key to navigating social group life. The Power Asymmetry Hypothesis of Motivational Emancipation predicts that the type of social organization shapes the meaning of communicative displays in relation to an individual's dominanc... Read More about Bared-teeth displays in bonobos (Pan paniscus): An assessment of the power asymmetry hypothesis.

Vocal functional flexibility: what it is and why it matters (2022)
Journal Article
Derry, T., Clay, Z., Dahl, C., Zuberbühler, J., Davila-Ross, M., & Dezecache, G. (2022). Vocal functional flexibility: what it is and why it matters. Animal Behaviour, 186, 93-100. https://doi.org/10.1016/j.anbehav.2022.01.015

Human speech is marked by a signal–function decoupling, the capacity to produce sounds that can fulfil a variety of functions, in contrast to nonverbal vocalizations such as laughter, cries and screams, which are functionally more rigid. It has been... Read More about Vocal functional flexibility: what it is and why it matters.

What makes us apes? The emotional building blocks of intersubjectivity in hominids (2022)
Journal Article
Demuru, E., Clay, Z., & Norscia, I. (2022). What makes us apes? The emotional building blocks of intersubjectivity in hominids. Ethology Ecology and Evolution, 34(3), 220-234. https://doi.org/10.1080/03949370.2022.2044390

Intersubjectivity, which refers to the capacity to create shared value or connection between individuals, is a complex and multi-faceted phenomenon involving both cognitive and affective components. Intersubjectivity has often been lauded as one of t... Read More about What makes us apes? The emotional building blocks of intersubjectivity in hominids.

Comparative Perspectives of Empathy Development: Insights from chimpanzees and bonobos (2022)
Book Chapter
Clay, Z., Webb, C., Romero, T., & de Waal, F. (2022). Comparative Perspectives of Empathy Development: Insights from chimpanzees and bonobos. In D. Dukes, E. Walle, & A. Samson (Eds.), The Oxford Handbook of Emotional Development (277-290). Oxford University Press. https://doi.org/10.1093/oxfordhb/9780198855903.013.30

Empathy - the sharing and understanding of others’ emotions and thoughts - is considered a defining feature of what it means to be human. Although empathy underpins many of our social interactions and is thought to be evolutionarily ancient, its orig... Read More about Comparative Perspectives of Empathy Development: Insights from chimpanzees and bonobos.

Dominance style is a key predictor of vocal use and evolution across nonhuman primates (2021)
Journal Article
Kavanagh, E., Street, S. E., Angwela, F. O., Bergman, T. J., Blaszczyk, M. B., Bolt, L. M., …Slocombe, K. (2021). Dominance style is a key predictor of vocal use and evolution across nonhuman primates. Royal Society Open Science, 8(7), Article 210873. https://doi.org/10.1098/rsos.210873

Animal communication has long been thought to be subject to pressures and constraints associated with social relationships. However, our understanding of how the nature and quality of social relationships relates to the use and evolution of communica... Read More about Dominance style is a key predictor of vocal use and evolution across nonhuman primates.

Anthropomorphism in comparative affective science: Advocating a mindful approach (2020)
Journal Article
Williams, L. A., Brosnan, S. F., & Clay, Z. (2020). Anthropomorphism in comparative affective science: Advocating a mindful approach. Neuroscience & Biobehavioral Reviews, 115, 299-307. https://doi.org/10.1016/j.neubiorev.2020.05.014

Anthropomorphism is the attribution of human-like capacities and traits to non-human entities. Anthropomorphism is ubiquitous in everyday life and in scientific domains, operating both implicitly and explicitly as a function of the human lens through... Read More about Anthropomorphism in comparative affective science: Advocating a mindful approach.

Emotional expressions in human and non-human great apes (2020)
Journal Article
Kret, M., Prochazkova, E., Sterc, E. M., & Clay, Z. (2020). Emotional expressions in human and non-human great apes. Neuroscience & Biobehavioral Reviews, 115, 378-395. https://doi.org/10.1016/j.neubiorev.2020.01.027

Humans and great apes are highly social species, and encounter conspecifics throughout their daily lives. During social interactions, they exchange information about their emotional states via expressions through different modalities including the fa... Read More about Emotional expressions in human and non-human great apes.

Ethological Approaches to Empathy in Primates (2018)
Book Chapter
Clay, Z., Palagi, E., & de Waal, F. B. (2018). Ethological Approaches to Empathy in Primates. In K. Meyza, & E. Knapska (Eds.), Neuronal correlates of empathy – from rodent to man. Elsevier

Ethological Approaches to Empathy in Primates (2018)
Book Chapter
Clay, Z., Palagi, E., & de Waal, F. B. (2018). Ethological Approaches to Empathy in Primates. In K. Meyza, & E. Knapska (Eds.), Neuronal Correlates of Empathy: From Rodent to Man (53-66). Academic Press