Avian Expert Articles

How Dr. Pepperberg Chooses What Topics To Study

African grey parrotOne of the many questions I’m often asked is how we choose topics to study. Specifically, where do we get our inspiration? Our choice of studies is actually influenced by several different issues, and I’ll discuss a few of them in some detail.

Will Others Like It?

The first issue is, not surprisingly, whether the topic would be of interest to my colleagues. If no one would want to read the eventually published paper, we have very little incentive to perform the study. Thankfully, both colleagues and owners of companion birds do seem to want to know how a bird with a brain the size of a shelled walnut stacks up against species as disparate as, for example, children, adult humans, apes, cetaceans, and monkeys.

We therefore often compare the abilities of our birds to those of other species, replicating existing research to provide a comparative approach. So, after attending a seminar or a conference and learning about studies in different laboratories, we often choose to examine how African grey parrots fare on various cognitive tasks. We may or may not have to adapt other labs’ procedures based on our parrots’ abilities. If, for example, a study involves young children’s vocal responses, and our parrots have similar labels in their repertoire, we generally use almost identical procedures.

Interestingly, however, we often have to perform additional controls that researchers studying children will ignore — for example, making sure that there are no olfactory cues, or that the students are not cuing the birds with body/head/eye gestures. Thus our protocol is often more exacting than those used for humans! If the human or nonhuman primate study involves pointing, we have to adapt the protocol so that our African greys can indicate the correct response by tapping with their beaks. We therefore spend a lot of time reading about research on many different species.

Student Inspiration

Another source of inspiration comes from my students. The final exam in every course I teach is always the assignment to design an experiment on animal cognition. If students design a really cool study, I’ll ask them if they want to become a research assistant in my lab to try out their idea on our parrots. Of course, an undergraduate usually doesn’t present a project that is completely ready to administer to the birds, but we work together to design the appropriate controls and refine the methodology. A paper based on one such exam paper (looking at probabilistic reasoning) has just been accepted for publication, and I’ll describe the results in detail in a forthcoming blog.

The bases for the experiments described above often originate with classic studies on children, like those designed by Jean Piaget (1936), or on chimpanzees, like those designed by David Premack (1983). Examples of the former involve our studies on object permanence (knowing that an object still exists even after it is hidden, e.g., Pepperberg, Willner & Gravitz, 1997) and liquid conservation (knowing that changes in shape do not affect changes in volume; Pepperberg et al., 2017); examples of the latter involve our studies on concepts of same/different (knowing not just that two objects are either identical or totally different, but that they can share some attributes and differ on others, Pepperberg, 1987).

Sometimes the experiments involve examining phenomena such as how our birds respond to classic optical illusions, often because another avian species does not process the illusion as do humans, and we want to see if African greys are more like humans or pigeons (more like humans: Pepperberg & Nakayama, 2016; Pepperberg, Vicinay, & Cavanagh, 2008).


Occasionally, however, colleagues design novel experiments to test a previously unstudied or understudied concept in another species and we decide to collaborate — either adapting their proposed protocols for our birds or designing protocols that are identical for the birds and humans. That has been the case with an ongoing study on visual working memory manipulation — determining if Griffin can process as much, more, or less information than adult humans or children. (Hint: He’s pretty good!)

It would be fun to figure out a task that no one has ever given any other subject, to see how our birds perform, and then have everyone else replicate our work … but right now, so many studies already exist that are just waiting for a comparative perspective; we have our work cut out for us for many years!

Piaget, J. (1936). La naissance de l’intelligence (The origins of intelligence). Neuchatel, Switzerland: Delachaux et Niestle.

Pepperberg, I.M. (1987b). Acquisition of the same/different concept by an African Grey parrot (Psittacus erithacus): Learning with respect to categories of color, shape, and material. Animal Learning & Behavior, 15, 423 432.

Pepperberg, I.M., Gray, S., Lesser, J.S., & Hartsfield, L.A. (2017). Piagetian liquid conservation in Grey parrots (Psittacus erithacus). Journal of Comparative Psychology. 10.1037/com0000085

Pepperberg, I.M., & Nakayama, K. (2016). Robust representation of shape by a Grey parrot (Psittacus erithacus). Cognition, 153, 146-160.

Pepperberg, I.M., Vicinay, J., Cavanagh, P. (2008) The Müller-Lyer illusion is processed by a Grey Parrot (Psittacus erithacus). Perception, 37, 765-781.

Pepperberg, I.M., Willner, M.R., & Gravitz, L.B. (1997). Development of Piagetian object permanence in a Grey parrot (Psittacus erithacus). Journal of Comparative Psychology, 111, 63-75.

Premack, D. (1983). The codes of man and beast. Behavioral & Brain Sciences, 6, 125–167.


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