I'm a biopsychologist with primary interests in nonverbal communication by apes and humans  and behavioural indices of anxiety.  I have primarily studied visual and vocal communication in apes (since 1994) and humans (since 2000), with a special emphasis on joint attention, or the negotiation of shared attentional focus.  This ability to follow into another's attentional focus, or to re-direct the attention of another, takes months to develop in our own species, and I have been exploring the socio-ecological influences on joint attention in apes and humans.  This work on non-verbal reference has led my colleagues and I to posit a Referential Problem Space, in which pointing and other mechanisms for joint attention emerge when organisms capable of means-ends reasoning are reliant upon others to act on the world for them--a situation that characterises both human infants and captive apes. 

Much of my research into chimpanzee communication stems from a disturbing realisation, in 1994, that I had been trained to a high standard of performance by a chimpanzee named Clint.

Most of my publications are available at:

Past and current research topics include:


1. How chimpanzees manipulate the attention of their social partners, with Prof. William D. Hopkins, Ms. Jamie L Russell, and Dr. Jared P. Taglialatela, Yerkes National Primate Research Center, Prof. Kim A. Bard, University of Portsmouth, and Prof. Richard Byrne and Dr. Cat Hobaiter, University of St Andrews.

Representative publications:

Leavens, D. A., Reamer, L. A., Mareno, M. C., Russell, J. L., Wilson, D., Schapiro, S. J., & Hopkins, W. D. (2015). Distal communication by chimpanzees (Pan troglodytes): Evidence for common ground? Child Development86, 1623-1638.

Bard, K. A., Bakeman, R., Boysen, S. T., & Leavens, D. A. (2014). Emotional engagements predict and enhance social cognition in young chimpanzees.  Developmental Science, 17, 682-696.

Hobaiter, C., Leavens, D. A., & Byrne, R. W. (2014). Deictic gesturing in wild chimpanzees? Some possible cases. Journal of Comparative Psychology, 128, 82-87. 

Leavens, D. A., Russell, J. L., & Hopkins, W. D. (2010). Multimodal communication by captive chimpanzees (Pan troglodytes).  Animal Cognition, 13, 33-40.


2. The ecological determinants of pointing: Pointing, as a phenotype, has virtually nil heritability among great apes, suggesting (a) that pointing is an ontogenetic adaptation to particular ecological constraints and (b) that perhaps pointing also develops in humans because of universal environmental constraints on free movement.

Representative publications:

Clark, H., & Leavens, D. A. (2019). Testing dogs in ape-like conditions: The effect of a barrier on dogs’ performance on the object choice task. Animal Cognition. Epub in advance of print.

Flack, Z., Naylor, M., & Leavens, D. A. (2018). Pointing to visible and invisible targets. Journal of Nonverbal Behavior42, 221-236.

Leavens, D. A. (2014). The plight of the sense-making ape. In M. Cappuccio & T. Froese (Eds.), Enactive cognition at the edge of sense-making (pp. 81-104). Basingstoke, U.K.: Palgrave Macmillan.

Leavens, D. A. (2012). Pointing: Contexts and instrumentality. In S. Pika & K. Liebal (Eds.), Current developments in primate gesture research (pp. 181-197). Amsterdam: Benjamins.

Leavens, D. A., & Bard, K. A. (2011). Environmental influences on joint attention in great apes: Implications for human cognition. Journal of Cognitive Education and Psychology10, 9-31.

Leavens, D. A., Hopkins, W. D., & Bard, K. A. (2008). The heterochronic origins of explicit reference.  In J. Zlatev, T. Racine, C. Sinha, & E. Itkonen (Eds.), The shared mind: Perspectives on intersubjectivity (pp. 187-214). Amsterdam: John Benjamins.

Leavens, D. A., Hopkins, W. D., & Bard, K. A. (2005). Understanding the point of chimpanzee pointing: Epigenesis and ecological validity. Current Directions in Psychological Science, 14, 185-189.

Leavens, D. A. (2004). Manual deixis in apes and humans. Interaction Studies, 5, 387-408. [Reprinted in C. Abry, A. Vilain, & J-L. Schwartz (Eds.), (2009). Vocalize to localize, pp. 67-86, Amsterdam: John Benjamins.]


3. Principles of comparative cognition: The contemporary literature is filled with poorly substantiated claims for human uniqueness in social cognition, and much of my recent effort is directed towards correcting the empirical record, with a wide circle of collaborators, including Prof. William D. Hopkins (Georgia State University), Dr. Heidi Lyn (The University of Southern Mississippi University), Prof. Kim Bard (University of Portsmouth), and my students, here at the University of Sussex.

Representative publications:

Leavens, D. A., & Bard, K. A. (In press). Primate cognition in captivity. In A. Lock, C. Sinha, and N. Gontier (Eds.), Oxford Handbook of Human Symbolic Evolution.  Oxford: Oxford University Press.

Leavens, D. A., Bard, K. A., & Hopkins, W. D. (2019). The mismeasure of ape social cognition. Animal Cognition, 22, 487-504.

Clark, H., Elsherif, M., & Leavens, D. A. (2019). Ontogeny vs. phylogeny in Primate/Canid comparisons: A meta-analysis of the object choice task. Neuroscience and Biobehavioral Reviews, 105, 178-189.

Leavens, D. A. (2018). The cognitive implications of intentional communication: A multi-faceted mirror. In L. Di Paolo, F. Di Vincenzo, & F. De Petrillo (Eds.), Evolution of primate social cognition (pp. 59-77). New York: Springer.

Leavens, D. A. (2014). The plight of the sense-making ape. In M. Cappuccio & T. Froese (Eds.), Enactive cognition at the edge of sense-making (pp. 81-104). Basingstoke, U.K.: Palgrave Macmillan.

Lyn, H., Russell, J. L., Leavens, D. A., Bard, K. A., Boysen, S. T., Schaeffer, J., & Hopkins, W. D. (2014). Apes communicate about absent and displaced objects: Methodology matters. Animal Cognition17, 85-94.

Hopkins, W. D., Russell, J. L., McIntyre, J., & Leavens, D. A. (2013). Are chimpanzees really so poor at understanding imperative pointing? Some new data and an alternative view of canine and ape social cognition. PLoS ONE8, e79338.

Thomas, E., Murphy, M., Pitt, R., Rivers, A., & Leavens, D. A. (2008). Understanding of visual attention by adult humans (Homo sapiens): A partial replication of Povinelli, Bierschwale, and Čech (1999). Journal of Comparative Psychology, 122, 428-436.


4. How self-directed behaviours (such as scratching) by chimpanzees and humans change in response to manipulations of task difficulty or anxiety, with Dr. Filippo Aureli, Liverpool Johns Moore University, and Dr. Bill Hopkins, Yerkes National Primate Research Center. (1996-2006).  More recent studies with Mr. Tom Brittain and Ms. Megan Denne are in preparation.

Representative publications:

Hopkins, W. D., Russell, J., Freeman, H., Reynolds, E. A. M., Griffis, C., & Leavens, D. A. (2006). Lateralized scratching in chimpanzees: Evidence of a functional asymmetry during arousal. Emotion, 6, 553-559.

Leavens, D. A., Aureli, F., Hopkins, W. D. (2004). Behavioral evidence for the cutaneous   expression of emotion in a chimpanzee (Pan troglodytes). Behaviour, 141, 979-997.

Leavens, D. A., Aureli, F., Hopkins, W. D., & Hyatt, C. W. (2001). The effects of cognitive challenge in self-directed behaviors by chimpanzees (Pan troglodytes). American Journal of Primatology, 55, 1-14.


5. Epistemological foundations of social cognitive development in human infants and apes, with Prof. Kim Bard, University of Portsmouth (1994-present), Dr. Timothy Racine, Simon Fraser University, Canada (2006-present), and Dr. Tom Froese, Universidad Nacional Autonoma de Mexico (formerly at University of Sussex), Mexico  (2012-present).

Representative publications:

Bard, K. A., & Leavens, D. A. (2014). The importance of development for comparative primatology. Annual Review of Anthropology43, 183-200.

Froese, T., & Leavens, D. A. (2014). The direct perception hypothesis: Perceiving the intention of another’s action hinders its precise imitation. Frontiers in Psychology, 5(65), 1-15

Racine, T. P., Wereha, T. J., & Leavens, D. A. (2012). To what extent nonhuman primates are intersubjective and why. In A. Foolen, U. Luedtke, J. Zlatev, & T. P. Racine (Eds.), Moving ourselves, moving others: The role of (e)motion in intersubjectivity, consciousness and language (pp. 221-242). Amsterdam: Benjamins.

Leavens, D. A., Bard, K. A., & Hopkins, W. D. (2010). BIZARRE chimpanzees do not represent “the chimpanzee.” Behavioral and Brain Sciences, 33, 100-101.


6. Lateral asymmetries in great ape and human behaviour; inductive models of praxis, with Prof. William D. Hopkins, Georgia State University (1994-present) and Dr. Gillian S. Forrester, University of Westminster (formerly at University of Sussex) (2005-present).

Representative publications:

Forrester, G. S., Quaresmini, C., Leavens, D. A., Mareschal, D., & Thomas, M. S. (2013). Human handedness: An inherited evolutionary trait. Behavioural Brain Research, 237, 200-206.

Forrester, G. S., Quaresmini, C., Leavens, D. A., Spiezio, C. & Vallortigara, G. (2012). Target animacy influences chimpanzee handedness. Animal Cognition, 15, 1121-1127.

Forrester, G. S., Leavens, D. A., Quaresmini, C., & Vallortigara, G. (2011). Target animacy influences gorilla handedness. Animal Cognition, 14, 903-907.

Hopkins, W. D., & Leavens, D. A. (1998). Hand use and gestural communication in chimpanzees (Pan troglodytes).  Journal of Comparative Psychology, 112, 95-99.


7. How human babies and their parents share attention, with Dr. Brenda Todd, City University (formerly University of Sussex) (2000-present).

Representative publication:

Leavens, D. A., Sansone, J., Burfield, A. R., Lightfoot, S., O'Hara, S., & Todd, B. K. (2014). Putting the 'joy' in joint attention: Affective-gestural synchrony by parents who point for their babies. Frontiers in Psychology5(879), 1-7.


8. Age-related changes in mirror self-recognition in human children, with Prof. Kim Bard, University of Portsmouth, and Dr. Brenda Todd, City University (formerly University of Sussex) (2004-2006).

Representative publication:

Bard, K. A., Todd, B. K., Bernier, C., Love, J., & Leavens, D. A. (2006). Self-awareness in human and chimpanzee infants: What is measured and what is meant by the mirror-and-the-mark test? Infancy9, 191-219.

(Updated 2 October 2019)