Token-Exchange Studies

By having apes exchange tokens for treats, scientists can study responses to unequal treatment.

Studying How Apes Respond to Unequal Treatment

Like humans, chimpanzees respond negatively to inequity. So when a chimpanzee receives a less-preferred food reward than that of a groupmate, it often shows frustration by rejecting the lesser reward. 

Such responses to inequity, although robust, appear to vary across individuals and social contexts. To understand why, scientists at the Fisher Center are running studies to determine the circumstances under which chimpanzees respond to inequity. By setting up a system where apes can exchange tokens for foods of varying desirability, the scientists can alter rewards and study responses in the group.

Unlike chimpanzees, scientists know very little about whether gorillas respond to inequity. A parallel project will enable some first comparisons between chimpanzees and gorillas on the subject. Through these comparative studies, we aim to explore many unanswered questions about gorillas’ understanding of behavioral economics.


Staff

Steve Ross, Ph.D., is director of Lincoln Park Zoo's Lester E. Fisher Center for the Study and Conservation of Apes

Steve Ross, Ph.D.
Director, Lester E. Fisher Center for the Study and Conservation of Apes

Lydia Hopper, Ph.D., is a research scientist in Lincoln Park Zoo's Lester E. Fisher Center for the Study and Conservation of Apes

Lydia Hopper, Ph.D.
Research Scientist, Lester E. Fisher Center for the Study and Conservation of Apes

Laura Kurtcyz is a research assistant in Lincoln Park Zoo's Lester E. Fisher Center for the Study and Conservation of Apes.

Laura Kurtycz
Research Assistant, Lester E. Fisher Center for the Study and Conservation of Apes

Kristin Bonnie, Ph.D., is an adjunct scientist in Lincoln Park Zoo’s Lester E. Fisher Center for the Study and Conservation of Apes

Kristin Bonnie, Ph.D.
Adjunct Scientist
Assistant Professor of Psychology, Beloit College


Learn More

The zoo's chimpanzees spent a year trading tokens for treats in a voluntary research project.

Post from the President—Trading Tokens
The zoo's chimpanzees spent a year trading tokens for treats in a voluntary research project. Whether they're taking the easy deal or hoarding for a big haul, these complex apes are showing us how they balance "work" and rewards.

By having chimpanzees trade tokens for treats, zoo scientists can study how the apes learn and respond to different rewards.

Great Ape Economics
By having chimpanzees trade tokens for treats, zoo scientists can study how the apes learn and respond to different rewards.