Staff profile

I am a comparative and developmental psychologist studying social cognition, empathy and emotions in great apes and humans, including children across cultures. My main interests are the development & evolution of social cognition and communication, focussing on empathy, emotional expressions, language and social learning. My research primarily takes a behavioural and psycho-physiological approach, using a combination of naturalistic observations, behavioural experiments and non-invasive technologies including eyetracking, thermal-imaging and pupillometry. 

Primary Research Interests 

Evolutionary & Cross-cultural Developmental Perspectives on:

• Social cognition and communication
• Empathy, emotion and emotion expressions
• Language evolution, vocalisations and gestures
• Social learning and culture

For comparative research, I am a specialist in great ape behaviour, with particular expertise in bonobos and chimpanzees, our closest living relatives. My research combines research in the wild, captivity and semi-captivity, including Lola ya Bonobo Sanctuary - where I also act as a long-term Scientific Consultant. 

For developmental research, I direct longitudinal research in Uganda and UK investigating the developmental origins of empathy, social cognition and emotion. I founded and co-direct the Budongo Families Project, a field-research site in Western Uganda where we work with a large local research team for cross-cultural psychological research with both children and adults.

I conducted my doctoral work at the University of St Andrews investigating bonobo vocal communication and language evolution before completing post-doctoral work with Prof Frans de Waal (Emory University, USA) on empathy development in bonobos. I conducted post-doctoral research in the Dept of Comparative Cognition, University of Neuchatel (Switzerland) on wild bonobo vocal communication along with a Marie Curie Research Fellowship at the University of Birmingham on the evolution & development of imitation and language. 

Available PhD and Masters (MSc by Research) projects

I welcome applications from people interested in doctoral and Masters research in the domains of comparative and developmental Psychology, including empathy,  social cognition and communication. I would be happy to supervise both experimental and observational projects working with human children, adults and primates. I have an excellent network of contacts to arrange access to a fieldsites for primate and cross-cultrural fieldwork. For those wishing to embark on a fieldwork PhD, experience of travel and work in third world countries is a real advantage.

Please contact me if you are interested in making an application

• Comparative Affective Science
• Evolution and development of empathy
• Evolution of language and culture
• Primate Conservation
• Primate behaviour
• Science outreach - primatology
• Social cognition
• Development of communication and social learning
• Primate vocal communication
• Animal cognition
• Child gesture development
• Applications to primate conservation

Chapter in book

• Comparative Perspectives of Empathy Development: Insights from chimpanzees and bonobos
  
  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 (pp. 277-290). Oxford University Press. https://doi.org/10.1093/oxfordhb/9780198855903.013.30
• Ethological Approaches to Empathy in Primates
  
  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
  
  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 (pp. 53-66). Academic Press.
• Natural communication in bonobos: Insights into social awareness and the evolution of language
  
  Clay, Z., & Genty, E. (2017). Natural communication in bonobos: Insights into social awareness and the evolution of language. In B. Hare & S. Yamamoto (Eds.), Bonobos: Unique in Mind Brain and Behavior. Oxford University Press. https://doi.org/10.1093/oso/9780198728511.003.0008
• Vocal communication and social awareness in chimpanzees and bonobos
  
  Clay, Z., & Zuberbuhler, K. (2014). Vocal communication and social awareness in chimpanzees and bonobos. In D. Dor, C. Knight, & J. Lewis (Eds.), The Social Origins of Language. Oxford University Press.
• Mirroring Fictional Others
  
  Clay, Z., & Iacoboni, M. (2011). Mirroring Fictional Others. In E. Schellekens & P. Goldie (Eds.), The Aesthetic Mind, Philosophy and Psychology. Oxford University Press.

Journal Article

• Bonobos innovate, plan, and transmit tool use to solve an extractive foraging task
  
  Zanutto, L., Funkhouser, J. A., Willems, E. P., Moser, A., Sanz, C., Clay, Z., & Koops, K. (2026). Bonobos innovate, plan, and transmit tool use to solve an extractive foraging task. IScience, 29(9), Article 117443. https://doi.org/10.1016/j.isci.2026.117443
• EXPRESS: Listen to Africa: nothing about us without us
  
  Oyekola, A., Ezeugwu, C., Ndyareeba, E., Clay, Z., Blumenthal, A., Cook, C., Blanchette, I., Draper, C., Milosavljevic, B., & Lloyd-Fox, S. (2026). EXPRESS: Listen to Africa: nothing about us without us. Quarterly Journal of Experimental Psychology. Advance online publication. https://doi.org/10.1177/17470218261490127
• A comparative approach to emotional crying in humans (Homo sapiens)—Tears as paedomorphic signals.
  
  Griffin, B., Clay, Z., Hyder-Wilson, R., & Abed, R. (2026). A comparative approach to emotional crying in humans (Homo sapiens)—Tears as paedomorphic signals. Journal of Comparative Psychology. Advance online publication. https://doi.org/10.1037/com0000454
• Reassuring body contact promotes social tolerance in bonobos and chimpanzees
  
  Brooker, J. S., Goldsborough, Z., van Leeuwen, E. J. C., Kordon, S., Webb, C. E., & Clay, Z. (2026). Reassuring body contact promotes social tolerance in bonobos and chimpanzees. Proceedings of the Royal Society B: Biological Sciences, 293(2075), Article 20253190. https://doi.org/10.1098/rspb.2025.3190
• Cultural Variation in Emotional Reactivity and Regulation in Infants From Uganda and the UK
  
  Vreden, C., Ndyareeba, E., Ainamani, H. E., Crowther, R., Donnelly, H., Forward, B., Kakai, B., Mazari, S., Paricia, J., Renner, E., Sajabi, J., Slocombe, K., Tuohy, G., & Clay, Z. (2026). Cultural Variation in Emotional Reactivity and Regulation in Infants From Uganda and the UK. Infancy, 31(4), Article e70116. https://doi.org/10.1111/infa.70116
• Helping Infants to Help: Cultural Variation in Maternal Scaffolding and the Development of Prosocial Behavior
  
  Vreden, C., Köster, M., Abbit, L., Ainembabazi, P., Cook, A., Kakai, B., Katusiime, P., Landstedt, J., Mazari, S., Ndyareeba, E., Renner, E., Tuohy, G., & Clay, Z. (2026). Helping Infants to Help: Cultural Variation in Maternal Scaffolding and the Development of Prosocial Behavior. Developmental Psychology. Advance online publication. https://doi.org/10.1037/dev0002159
• Social structure as a form of collective intelligence: a new framework
  
  Brooker, J. S., van Leeuwen, E. J. C., & Clay, Z. (2026). Social structure as a form of collective intelligence: a new framework. Philosophical Transactions B, 381(1948), Article 20240443. https://doi.org/10.1098/rstb.2024.0443
• Evolutionary theory and social diversity are essential for understanding the developmental origins of human social cognition and attachment
  
  Clay, Z., & Crockford, C. (2026). Evolutionary theory and social diversity are essential for understanding the developmental origins of human social cognition and attachment. Behavioral and Brain Sciences, 49, Article e265. https://doi.org/10.1017/S0140525X25104238
• How do young children respond to the distress of others? Applying infrared thermography and behavioural analyses to examine the development of emotion contagion and empathy
  
  Austry, D. A., Renner, E., & Clay, Z. (2026). How do young children respond to the distress of others? Applying infrared thermography and behavioural analyses to examine the development of emotion contagion and empathy. PLOS One, 21(3), Article e0335537. https://doi.org/10.1371/journal.pone.0335537
• The evolutionary and developmental origins of empathy: honouring Frans de Waal’s legacy
  
  Clay, Z. (2025). The evolutionary and developmental origins of empathy: honouring Frans de Waal’s legacy. Behaviour, 163(3-4), 215-231. https://doi.org/10.1163/1568539x-bja10342
• The physics of sociality: Investigating patterns of social resource distribution among the Pan species
  
  van Leeuwen, E. J., Escribano, D., Clay, Z., Eens, M., Guéry, J., Haun, D. B., Kordon, S., Nolte, S., Staes, N., Stevens, J. M., Torfs, J., Cuesta, J. A., & Sánchez, A. (2025). The physics of sociality: Investigating patterns of social resource distribution among the Pan species. IScience, 28(11), Article 113507. https://doi.org/10.1016/j.isci.2025.113507
• Maternal responsiveness to infant distress: A cross-cultural investigation in Uganda and the United Kingdom.
  
  Vreden, C., Atim, S., Buryn-Weitzel, J. C., Di Gregorio, G., Donnellan, E., Hoffman, M., Jurua, M., Knapper, C. V., Marshall, S., Paricia, J., Tusiime, F., Wilke, C., Slocombe, K. E., & Clay, Z. (2025). Maternal responsiveness to infant distress: A cross-cultural investigation in Uganda and the United Kingdom. Developmental Psychology. Advance online publication. https://doi.org/10.1037/dev0002038
• The Impact of Maternal Experience of Gender Roles on Children's Socio‐Emotional Development in Uganda: A Qualitative Study
  
  Tuohy, G., Ainamani, H., Kakai, B., Nydareeba, E., Paricia, J., Sajabi, J., Vreden, C., Boothroyd, L., & Clay, Z. (2025). The Impact of Maternal Experience of Gender Roles on Children’s Socio‐Emotional Development in Uganda: A Qualitative Study. Infant and Child Development, 34(4), Article e70048. https://doi.org/10.1002/icd.70048
• Collective Acoustics in Pan: Conserved Roots in the Evolution of Human Musicality
  
  Brooks, J., Clay, Z., Dufour, V., Fedurek, P., Girard-Buttoz, C., & Yamamoto, S. (2025). Collective Acoustics in Pan: Conserved Roots in the Evolution of Human Musicality. American Journal of Primatology, 87(6), Article e70048. https://doi.org/10.1002/ajp.70048
• Social contagion in primates: Moderating factors and significance for individuals and the group
  
  Sandars, G., & Clay, Z. (2025). Social contagion in primates: Moderating factors and significance for individuals and the group. Neuroscience and Biobehavioral Reviews, 173, Article 106156. https://doi.org/10.1016/j.neubiorev.2025.106156
• Early empathy development: Concern and comforting in 9- and 18-month-old infants from Uganda and the UK
  
  Vreden, C., Buryn-Weitzel, J. C., Atim, S., Donnellan, E., Hoffman, M., Holden, E., Jurua, M., Knapper, C. V., Lahiff, N. J., Marshall, S., Paricia, J., Tuncgenc, B., Tusiime, F., Wilke, C., Slocombe, K. E., & Clay, Z. (2025). Early empathy development: Concern and comforting in 9- and 18-month-old infants from Uganda and the UK. PLOS One, 20(5), Article e0320371. https://doi.org/10.1371/journal.pone.0320371
• Within-species variation eclipses between-species differences in Pan consolation
  
  Brooker, J. S., Webb, C. E., Kordon, S., de Waal, F. B., & Clay, Z. (2025). Within-species variation eclipses between-species differences in Pan consolation. Evolution and Human Behavior, 46(3), Article 106682. https://doi.org/10.1016/j.evolhumbehav.2025.106682
• Bonobos and chimpanzees overlap in sexual behaviour patterns during social tension
  
  Brooker, J. S., Webb, C. E., van Leeuwen, E. J. C., Kordon, S., de Waal, F. B. M., & Clay, Z. (2025). Bonobos and chimpanzees overlap in sexual behaviour patterns during social tension. Royal Society Open Science, 12(3), Article 242031. https://doi.org/10.1098/rsos.242031
• Conspecific alarm calls, but not food-associated calls, elicit affect-based and object-based mental representations in a bonobo (Pan paniscus)
  
  Lahiff, N. J., Clay, Z., Epping, A. J., Taglialatela, J. P., Townsend, S. W., & Slocombe, K. E. (2025). Conspecific alarm calls, but not food-associated calls, elicit affect-based and object-based mental representations in a bonobo (Pan paniscus). Royal Society Open Science, 12(3), Article 241901. https://doi.org/10.1098/rsos.241901
• Contagious Crying Revisited: A Cross‐Cultural Investigation Into Infant Emotion Contagion Using Infrared Thermal Imaging
  
  Vreden, C., Renner, E., Ainamani, H. E., Crowther, R., Forward, B., Mazari, S., Tuohy, G., Ndyareeba, E., & Clay, Z. (2025). Contagious Crying Revisited: A Cross‐Cultural Investigation Into Infant Emotion Contagion Using Infrared Thermal Imaging. Developmental Science, 28(2), Article e13608. https://doi.org/10.1111/desc.13608
• Categorization and discrimination of human and non-human primate affective vocalizations: Investigation of frontal cortex activity through fNIRS
  
  Debracque, C., Ceravolo, L., Clay, Z., Grandjean, D., & Gruber, T. (2025). Categorization and discrimination of human and non-human primate affective vocalizations: Investigation of frontal cortex activity through fNIRS. Imaging Neuroscience (Cambridge, Mass.), 3.
• Factors shaping socio-emotional trajectories in sanctuary-living bonobos: a longitudinal approach
  
  Kordon, S., Webb, C. E., Brooker, J. S., de Waal, F. B., & Clay, Z. (2024). Factors shaping socio-emotional trajectories in sanctuary-living bonobos: a longitudinal approach. Royal Society Open Science, 11(12), Article 240435. https://doi.org/10.1098/rsos.240435
• ChimpanSEE, ChimpanDO: Grooming and play contagion in chimpanzees
  
  Sandars, G., Brooker, J. S., & Clay, Z. (2024). ChimpanSEE, ChimpanDO: Grooming and play contagion in chimpanzees. PLOS ONE, 19(11), Article e0312467. https://doi.org/10.1371/journal.pone.0312467
• Impact of social context on human facial and gestural emotion expressions
  
  Heesen, R., Szenteczki, M. A., Kim, Y., Kret, M. E., Atkinson, A. P., Upton, Z., & Clay, Z. (2024). Impact of social context on human facial and gestural emotion expressions. IScience, 27(11), Article 110663. https://doi.org/10.1016/j.isci.2024.110663
• The expression of empathy in human's closest relatives, bonobos and chimpanzees: current and future directions
  
  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
• Frans de Waal - A pioneer who shone a light on the primate mind.
  
  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
• Perceptual integration of bodily and facial emotion cues in chimpanzees and humans
  
  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
• Increased alertness and moderate ingroup cohesion in bonobos’ response to outgroup cues
  
  Brooks, J., van Heijst, K., Epping, A., Lee, S. H., Niksarli, A., Pope, A., Clay, Z., Kret, M. E., Taglialatela, J., & Yamamoto, S. (2024). 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
• Group-specific expressions of co-feeding tolerance in bonobos and chimpanzees preclude dichotomous species generalizations
  
  van Leeuwen, E. J., Staes, N., Brooker, J. S., Kordon, S., Nolte, S., Clay, Z., Eens, M., & 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
• Multimodal communication development in semiwild chimpanzees
  
  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
• Between-group variation in production of pant-grunt vocalizations by wild bonobos (Pan paniscus)
  
  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
• Humans recognize affective cues in primate vocalizations: acoustic and phylogenetic perspectives
  
  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
• The Association Between the Bared-Teeth Display and Social Dominance in Captive Chimpanzees (Pan troglodytes)
  
  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
• Flexible signalling strategies by victims mediate post-conflict interactions in bonobos
  
  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
• Bared-teeth displays in bonobos (Pan paniscus): An assessment of the power asymmetry hypothesis
  
  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
• Vocal functional flexibility: what it is and why it matters
  
  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
• What makes us apes? The emotional building blocks of intersubjectivity in hominids
  
  Demuru, E., Clay, Z., & Norscia, I. (2022). What makes us apes? The emotional building blocks of intersubjectivity in hominids. Ethology Ecology & Evolution, 34(3), 220-234. https://doi.org/10.1080/03949370.2022.2044390
• Dominance style is a key predictor of vocal use and evolution across nonhuman primates
  
  Kavanagh, E., Street, S. E., Angwela, F. O., Bergman, T. J., Blaszczyk, M. B., Bolt, L. M., Briseño-Jaramillo, M., Brown, M., Chen-Kraus, C., Clay, Z., Coye, C., Thompson, M. E., Estrada, A., Fichtel, C., Fruth, B., Gamba, M., Giacoma, C., Graham, K. E., Green, S., … 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
• Anthropomorphism in comparative affective science: Advocating a mindful approach
  
  Williams, L. A., Brosnan, S. F., & Clay, Z. (2020). Anthropomorphism in comparative affective science: Advocating a mindful approach. Neuroscience and Biobehavioral Reviews, 115, 299-307. https://doi.org/10.1016/j.neubiorev.2020.05.014
• Emotional expressions in human and non-human great apes
  
  Kret, M., Prochazkova, E., Sterc, E. M., & Clay, Z. (2020). Emotional expressions in human and non-human great apes. Neuroscience and Biobehavioral Reviews, 115, 378-395. https://doi.org/10.1016/j.neubiorev.2020.01.027
• Higher fundamental frequency in bonobos is explained by larynx morphology
  
  Grawunder, S., Crockford, C., Clay, Z., Kalan, A., Stevens, J., Stoessel, A., & Hohmann, G. (2018). Higher fundamental frequency in bonobos is explained by larynx morphology. Current Biology, 28(20), R1188-R1189. https://doi.org/10.1016/j.cub.2018.09.030
• Is Overimitation a Uniquely Human Phenomenon? Insights From Human Children as Compared to Bonobos
  
  Clay, Z., & Tennie, C. (2018). Is Overimitation a Uniquely Human Phenomenon? Insights From Human Children as Compared to Bonobos. Child Development, 89(5), 1535-1544. https://doi.org/10.1111/cdev.12857
• What drives young children to over-imitate? Investigating the effects of age, context, action type, and transitivity
  
  Clay, Z., Over, H., & Tennie, C. (2018). What drives young children to over-imitate? Investigating the effects of age, context, action type, and transitivity. Journal of Experimental Child Psychology, 166, 520-534. https://doi.org/10.1016/j.jecp.2017.09.008
• Bonobos use call combinations to facilitate inter-party travel recruitment
  
  Schamberg, I., Cheney, D. L., Clay, Z., Hohmann, G., & Seyfarth, R. M. (2017). Bonobos use call combinations to facilitate inter-party travel recruitment. Behavioral Ecology and Sociobiology, 71(4), Article 75. https://doi.org/10.1007/s00265-017-2301-9
• Call combinations, vocal exchanges and interparty movement in wild bonobos
  
  Schamberg, I., Cheney, D. L., Clay, Z., Hohmann, G., & Seyfarth, R. M. (2016). Call combinations, vocal exchanges and interparty movement in wild bonobos. Animal Behaviour, 122, 109-116. https://doi.org/10.1016/j.anbehav.2016.10.003
• A Comparison Between Bonobos and Chimpanzees: A Review and Update
  
  Gruber, T., & Clay, Z. (2016). A Comparison Between Bonobos and Chimpanzees: A Review and Update. Evolutionary Anthropology, 25(5), 239-252. https://doi.org/10.1002/evan.21501
• Bonobos (Pan paniscus) vocally protest against violations of social expectations
  
  Clay, Z., Ravaux, L., de Waal, F. B., & Zuberbühler, K. (2016). Bonobos (Pan paniscus) vocally protest against violations of social expectations. Journal of Comparative Psychology, 130(1), 44-54. https://doi.org/10.1037/a0040088
• Obstacles and catalysts to peaceful coexistence in chimpanzees and bonobos.
  
  Clay, Z., de Waal, F. B., & Furuichi, T. (2016). Obstacles and catalysts to peaceful coexistence in chimpanzees and bonobos. Behaviour, 153(9-11), 1293-1330. https://doi.org/10.1163/1568539x-00003335
• Functional flexibility in wild bonobo vocal behaviour
  
  Clay, Z., Archbold, J., & Zuberbühler, K. (2015). Functional flexibility in wild bonobo vocal behaviour. PeerJ, 3, Article e1124. https://doi.org/10.7717/peerj.1124
• Contextually variable signals can be functionally referential
  
  Scarantino, A., & Clay, Z. (2015). Contextually variable signals can be functionally referential. Animal Behaviour, 100, e1-e8. https://doi.org/10.1016/j.anbehav.2014.08.017
• Sex and strife: post-conflict sexual contacts in bonobos.
  
  Clay, Z., & de Waal, F. B. (2015). Sex and strife: post-conflict sexual contacts in bonobos. Behaviour, 152(3-4), 313-334. https://doi.org/10.1163/1568539x-00003155
• Young Children Make Their Gestural Communication Systems More Language-Like: Segmentation and Linearization of Semantic Elements in Motion Events
  
  Clay, Z., Pople, S., Hood, B., & Kita, S. (2014). Young Children Make Their Gestural Communication Systems More Language-Like: Segmentation and Linearization of Semantic Elements in Motion Events. Psychological Science, 25(8), 1518-1525. https://doi.org/10.1177/0956797614533967
• Multi-Modal Use of a Socially Directed Call in Bonobos
  
  Genty, E., Clay, Z., Hobaiter, C., & Zuberbühler, K. (2014). Multi-Modal Use of a Socially Directed Call in Bonobos. PLoS ONE, 9(1), Article e84738. https://doi.org/10.1371/journal.pone.0084738
• Development of socio-emotional competence in bonobos
  
  Clay, Z., & de Waal, F. (2013). Development of socio-emotional competence in bonobos. Proceedings of the National Academy of Sciences, 110(45), 18121-18126. https://doi.org/10.1073/pnas.1316449110
• Bonobos Respond to Distress in Others: Consolation across the Age Spectrum
  
  Clay, Z., & de Waal, F. B. (2013). Bonobos Respond to Distress in Others: Consolation across the Age Spectrum. PLoS ONE, 8(1), Article e55206. https://doi.org/10.1371/journal.pone.0055206
• Communication during sex among female bonobos: effects of dominance, solicitation and audience
  
  Clay, Z., & Zuberbühler, K. (2012). Communication during sex among female bonobos: effects of dominance, solicitation and audience. Scientific Reports, 2, Article 291. https://doi.org/10.1038/srep00291
• Food-associated vocalizations in mammals and birds: what do these calls really mean?
  
  Clay, Z., Smith, C. L., & Blumstein, D. T. (2012). Food-associated vocalizations in mammals and birds: what do these calls really mean? Animal Behaviour, 83(2), 323-330. https://doi.org/10.1016/j.anbehav.2011.12.008
• The Structure of Bonobo Copulation Calls During Reproductive and Non-Reproductive Sex.
  
  Clay, Z., & Zuberbühler, K. (2011). The Structure of Bonobo Copulation Calls During Reproductive and Non-Reproductive Sex. Ethology, 117(12), 1158-1169. https://doi.org/10.1111/j.1439-0310.2011.01975.x
• Female bonobos use copulation calls as social signals.
  
  Clay, Z., Pika, S., Gruber, T., & Zuberbuhler, K. (2011). Female bonobos use copulation calls as social signals. Biology Letters, 7(4). https://doi.org/10.1098/rsbl.2010.1227
• Bonobos Extract Meaning from Call Sequences
  
  Clay, Z., & Zuberbühler, K. (2011). Bonobos Extract Meaning from Call Sequences. PLoS ONE, 6(4), Article e18786. https://doi.org/10.1371/journal.pone.0018786
• A comparison of bonobo and chimpanzee tool use: evidence for a female bias in the Pan lineage.
  
  Gruber, T., Clay, Z., & Zuberbühler, K. (2010). A comparison of bonobo and chimpanzee tool use: evidence for a female bias in the Pan lineage. Animal Behaviour, 80(6), 1023-1033. https://doi.org/10.1016/j.anbehav.2010.09.005
• Food-associated calling sequences in bonobos.
  
  Clay, Z., & Zuberbühler, K. (2009). Food-associated calling sequences in bonobos. Animal Behaviour, 77(6), 1387-1396. https://doi.org/10.1016/j.anbehav.2009.02.016