Conservation & Science Staff Bios

Lydia Hopper, Ph.D.

  Assistant Director
Lester E. Fisher Center for the Study and Conservation of Apes

Honorary Research Fellow
School of Psychology, University of Birmingham, England

Adjunct Assistant Professor
Department of Psychology, Northwestern University


  • Ph.D. –Social learning mechanisms of chimpanzees (Pan troglodytes) and children (Homo sapiens), University of St Andrews, UK
  • B.S. – Psychology & Zoology, University of Liverpool, UK

Areas of Expertise

  • Chimpanzee behavior
  • Primate social cognition
  • Comparative developmental psychology

About Lydia Hopper:

Lydia joined Lincoln Park Zoo in 2012 and works with Fisher Center Director Steve Ross, Ph.D., to design and coordinate the behavioral and cognitive research conducted by the Fisher Center team. These studies help us gain a deeper understanding of chimpanzee and gorilla behavior, which is vital for providing the best possible care to these complex and fascinating animals.

Lydia’s passion is primate social cognition: how individuals navigate their social world. To learn the most she can about nonhuman primate behavior—and to promote a comparative perspective—Lydia has been fortunate to work with a number of different species, including chimpanzees, gorillas, orangutans, rhesus macaques and squirrel monkeys.

Through her research, Lydia has not only highlighted many nuances of nonhuman primate behavior but has also shown how it compares and relates to our own behavioral strategies. Her expertise centers on social learning and behavioral economics. The first of these subjects—social learning—describes how an individual gains new skills from observing experienced individuals, such as when an infant chimpanzee watches her mother use stone tools to crack nuts.

In 2010, Lydia joined the Language Research Center at Georgia State University. There, in collaboration with researchers at the University of Texas MD Anderson Cancer Center, she broadened the scope of her research to include studies of her second focus: behavioral economics.

Like us, certain primate species react negatively to receiving a less-preferred reward than the one given to a social partner. By combining her knowledge of social learning with this new topic of investigation, Lydia was able to help tease apart some of the individual and social factors that explain when and why apes and monkeys respond to inequity.


Wagner, K.E., Hopper, L.M., & Ross, S.R. 2015. Asymmetries in the production of self-directed behavior by chimpanzees and gorillas during a computerized cognitive test. Animal Cognition: in press.

Hopper, L.M., Kurtycz, L.M., Ross, S.R., & Bonnie, K.E. 2015. Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting. PeerJ 3, e833.

Kendal, R.L., Hopper, L.M., Whiten, A., Brosnan, S.F., Lambeth, S.P., Schapiro, S.J., & Hoppitt, W. 2015. Chimpanzees copy dominant and knowledgeable individuals: implications for cultural diversity. Evolution & Human Behavior. 36, 65-72.

Hopper, L.M., Tennie, C., Ross, S.R. & Lonsdorf, E.V. 2015. Chimpanzees create and modify probe-tools functionally: A study with zoo-housed chimpanzees. American Journal of Primatology 77(2), 162-170.

Brosnan, S.F., Hopper, L.M., Richey, S., Freeman, H.D., Talbot, C.F., Gosling, S., Lambeth, S.P. & Schapiro, S.J. 2015. Personality influences responses to inequity and contrast in chimpanzees. Animal Behaviour 101, 75-87.

Claidière, N., Whiten, A., Mareno, M.C., Messer, E., Brosnan, S.F., Hopper, L.M., Lambeth, S.P., Schapiro, S.J., & McGuigan, N. 2015. Selective and contagious prosocial resource donation in capuchin monkeys, chimpanzees and humans. Scientific Reports 5, 7631.

Hopper, L.M., Lambeth, S.P., Schapiro, S.J. & Whiten, A. 2015. The importance of witnessed agency in chimpanzee social learning of tool use. Behavioural Processes 112, 120-129.

Finestone, E., Bonnie, K.E., Hopper, L.M., Vreeman, V.M., Lonsdorf, E.V., & Ross, S.R. 2014. The interplay between individual, social, and environmental influences on chimpanzee food choices. Behavioural Processes. 105, 71-78.

Hopper, L.M. 2014. Do chimpanzees (Pan troglodytes) choose to exert control over their environment to maximize personal gain in comparison to their peers?. American Society of Primatologists Bulletin, Spring/Summer 2014, 43-52.

Hopper, L.M., Price, S.A., Freeman, H.D., Lambeth, S.P., Schapiro, S.J. & Kendal, R.L. 2014. Influence of personality, age, sex, and estrous state on chimpanzee problem-solving success. Animal Cognition. 17(4), 835-847.

Brosnan, S.F. & Hopper, L.M. 2014. Psychological limits on animal innovation. Animal Behaviour. 92, 325-332.

Hopper, L.M., Lambeth, S.P., Schapiro, S.J., & Brosnan, S.F. 2014. Social comparison mediates chimpanzees' responses to loss, not frustration. Animal Cognition. 17(6), 1303-1311.

Pasquaretta, C., Levé, M., Claidière, N., van de Waal, E., Whiten, A., Macintosh, A., Pelé, M., Bergstrom, M., Borgeaud, C., Brosnan, F., Crofoot, M., Fedigan, L., Fichtel, C., Hopper, L.M., Mareno, M., Petit, O., Schnoell, A.V., Polizzi di Sorrentino, E., Thierry, B., Tiddi, B. & Sueur, C. 2014. Social networks in primates: smart and tolerant species have more efficient networks. Scientific Reports 4, 7600.

Hopper, L.M., Morgan, D.B., & Ross, S.R. 2014. The next direction for primatology? A commentary on Setchell (2013). International Journal of Primatology. 35(2), 341-348.

Brosnan, S.F. & Hopper, L.M. 2013. Cooperation, behavioral diversity and inequity responses. In M. Banaji & S. Gelman (Eds.) Navigating the Social World: What Infants, Children, and Other Species Can Teach Us. (pp. 371-376). Oxford University Press: New York, NY.

Freeman, H.D., Brosnan, S.F., Hopper, L.M., Lambeth, S.P., Schapiro, S.J. & Gosling, S.D. 2013. Developing a comprehensive and comparative questionnaire for measuring personality in chimpanzees using a simultaneous top-down/bottom-up design. American Journal of Primatology, 75: 1042-1053.

Freeman, H.D., Sullivan, J., Hopper, L.M., Talbot, C.F., Holmes, A.N., Schultz-Darken, N., Williams, L.E. & Brosnan, S.F. 2013. Different responses to reward comparisons by three primate species. PLoS ONE 8(10): e76287.

Ross, M.R., Gillespie, K.L., Hopper, L. M., Bloomsmith, M.A., & Maple, T.L. 2013. Differential preference for ultraviolet light among captive birds from three ecological habitats. Applied Animal Behaviour Science 147: 278-285.

Hopper, L.M., Holmes, A.N., Williams, L.E., & Brosnan, S.F. 2013. Dissecting the mechanisms of squirrel monkey (Saimiri boliviensis) social learning. PeerJ 1:e13. DOI: 10.7717/peerj.13.

Hopper, L.M., Lambeth, S.P., Schapiro S.J., Bernacky, B.J., & Brosnan, S.F. 2013. The ontogeny of social comparisons in rhesus macaques (Macaca mulatta). Journal of Primatology, 2:109.

Hopper, L.M., Lambeth, S.P., Schapiro, S.J. & Brosnan S.F. 2013. When given the opportunity, chimpanzees maximize personal gain rather than “level the playing field”. PeerJ. 1: e165.

Hopper, L.M., Lambeth, S.P. & Schapiro, S.J. 2012. An evaluation of the efficacy of video displays for use with chimpanzees (Pan troglodytes). American Journal of Primatology. 74, 442-449.

Caldwell. C.A., Schillinger, K., Evans, C.L., & Hopper, L.M. 2012. End state copying by humans (Homo sapiens): Implications for a comparative perspective on cumulative culture. Journal of Comparative Psychology. 126, 161-169.

Hopper, L.M. & Brosnan, S.F. 2012. Primate cognition. Nature Education Knowledge 5(8):3.

Hopper, L.M., Marshall-Pescini, S. & Whiten, A. 2012. Social learning and culture in child and chimpanzee. In F.B.M. de Waal & P.F. Ferrari (Eds.) The Primate Mind: Built to Connect with Other Minds. (pp. 99-118). Harvard University Press: Cambridge, MA.

Hopper, L.M. & Whiten, A. 2012. The evolutionary and comparative psychology of social learning and culture. In J. Vonk & T. K. Shackelford (Eds.) The Oxford Handbook of Comparative Evolutionary Psychology. (pp.451-473). Oxford University Press: New York, NY.

Hopper, L.M., Schapiro, S.J., Lambeth, S.P. & Brosnan, S.F. 2011. Chimpanzees’ socially maintained food preferences indicate both conservatism and conformity. Animal Behaviour. 81, 1195-1202.

Hopper, L.M. 2010. Deferred imitation in children and apes. Children imitate after a delay, but can apes ape in a similar fashion?. The Psychologist. 23, 294-297.

Hopper, L.M., Flynn, E., Wood, L.A.N. & Whiten, A. 2010. Observational learning of tool use in children: Investigating cultural spread through diffusion chains and learning mechanisms through ghost displays. Journal of Experimental Child Psychology. 106, 82-97.

Hopper, L.M. 2010. ‘Ghost’ experiments and the dissection of social learning in humans and animals. Biological Reviews. 85, 685-701.

Whiten, A., McGuigan, N., Marshall-Pescini, S. & Hopper, L.M. 2009. Emulation, imitation, over-imitation and the scope of culture for child and chimpanzee. Philosophical Transactions of the Royal Society B. 364, 2417-2428.

Hopper, L.M., Lambeth, S.P., Schapiro, S.J. & Whiten, A. 2008. Observational learning in chimpanzees and children studied through ‘ghost’ conditions. Proceedings of the Royal Society B. 275, 835–840.

Hopper, L.M., Spiteri, A., Lambeth, S.P., Schapiro, S.J., Horner, V. & Whiten, A. 2007. Experimental studies of traditions and underlying transmission processes in chimpanzees. Animal Behaviour.73, 1021-1032.