Hominoid Psychology Research Group


Our Research Goals

Our First Goal

Is to determine which features of human social problem-solving and decision-making are unique amongst the hominoids – bonobos, chimpanzees, humans, gorillas and orangutans. (See "interactive ape family tree" in right column.) Identifying those psychological systems which are responsible for the unique features of human behavior is the first step to solving Darwin's greatest difficulty.

Knowing our evolutionary relationship to the other apes (our phylogeny) and the principle of parsimony allow us to take this first step.

Phylogeny: Our species shared an ancestor with bonobos and chimpanzees ~6 million years ago which means by comparing humans with bonobos and chimpanzees we can determine how our species' psychology changed since all three species shared a common ancestor. (NOTE: humans evolved from a common ancestor with chimpanzees and bonobos not directly from them. Bonobos and chimpanzees have also changed since they split from our common ancestor since they are now separate species!)

Parsimony: If bonobos and chimpanzees lack psychological systems that humans possess, we know these systems evolved since humans diverged from our last common ancestor. When bonobos, chimpanzees and humans are similar psychologically it is most parsimonious to assume all three species inherited this psychology from their common ancestor (it did not evolve three times independently).

Our Second Goal

Is to identify the evolutionary process by which cognition evolves between different species – including the process that led to the evolution of the unique features of human psychology. Understanding the selective pressures that can drive the evolution of such psychological systems is the second step in solving Darwin's greatest difficulty.

Comparing the psychology of primates and non-primates to identify cases of psychological convergence (where distantly related species share similar psychological traits) allows us to take this second step.

Convergence: If the psychology of two distantly related species converge, it is possible these shared traits arose independently due to similar selective pressures (i.e., high levels of tolerance in domesticated animals, bonobos and humans may be the result of similar selection pressures). Therefore, cases of convergence may provide a unique opportunity to infer how human-like problem-solving skills evolve.

Research Resources

We conduct our non-invasive behavioral research with chimpanzees and bonobos at:

Both are African sanctuaries belonging to the Pan African Sanctuary Alliance and are on the front lines in the fight against the illegal, international bushmeat trade threatening wild apes with extinction. By studying apes in African sanctuaries we hope to obtain the most accurate picture of what apes are capable of while supporting welfare and conservation efforts in African sanctuaries. Therefore, we are also actively involved in conservation and welfare research.

We also conduct research locally with great apes, lemurs and dogs at:

The Hare Group also runs the Duke Canine Cognition Center.