Dr. Pepperberg Dishes: Will Parrots Work For Food?

The Work Ethic

You have a choice between toiling hard for your living or receiving everything you need for free. Sounds like a no-brainer, right? Who wouldn’t want life to be as easy as possible? Why spend resources (such as energy) if one doesn’t have to do so? Well, that’s actually not what researchers find for almost every subject tested when the choice involves food — except, interestingly, domestic cats!

Work for Food?

The technical term for choosing to work for a reward rather than getting it for free is called “contra-freeloading.” The first study of this behavior was in in rats, by Glen Jensen (1963). He found that rats would work for about 50% of their daily ration even if they could receive 100% for free. Initially, the scientific community believed that the finding was specific to rats: That, because of their feeding strategies in nature, they might figure that the food for which they had to work was an ephemeral source that they had to exploit for as long as possible and that the free food would be around as backup. Whether this explanation is valid or not, subsequent studies, on creatures from pigeons (Neuringer, 1969) to grizzly bears (McGowan et al., 2010) and apes (Menzel, 1991) showed that the phenomenon was widespread. It’s even been shown in humans (Tarte, 1981).

As someone who studies parrot cognition, most interesting to me was a study recently presented at the International Ethological Congress in Portugal. The experiment involved an exchange paradigm, in which parrots could choose either a token they could trade for a particular food or some food itself. If the token represented a lesser-quality food than the food choice, the birds chose the food item; if the token represented a higher quality food, the birds chose the token and traded up. The critical trials were where the token represented the same quality food as the food item presented, as that would actually test for contra-freeloading.

The researcher tested four species: great green macaws, blue-throated macaws, blue-headed macaws, and Grey parrots. Although the great green macaws seemed to prefer the food, the other three macaw species and grey parrots all chose the token. So, where am I going with this?

Foraging Caters To A Parrot’s Wild Instincts 

Although I can’t figure out why the one species of macaw would act more like domestic cats than any of the other species, it was clear that the other parrots really wanted to play the game. And that finding suggests the real importance of providing foraging opportunities for our parrots. In the wild, most parrot species (including those great green macaws) travel long distances every day and have to work fairly hard to get their nourishment. For example, African greys crack nuts, eviscerate fruits, and juice bark (May, 2004). Such behavior is part and parcel of their lives. They are not made to be “perch-potatoes,” simply sitting around and eating out of a dish.

In captivity, having the chance to figure out a new foraging toy is probably one of the most interesting parts of their day. They really seem to enjoy the challenge of learning about the affordances of such toys. And as I wrote in last month’s blog, one of our Greys, Athena, was most annoyed when we failed to fill her foraging toy, even when she could eat the same food from her bowl. Sometimes, too, I think my birds like to ask for specific treats not because they really want the foods, but because they want the social interactions with the students who are providing the items!

In sum, when owners provide foraging toys — particularly if several are provided at once — our birds aren’t merely being provided with a distraction. They are being given a choice as to how they wish to spend their time, and also some control over how they choose to live their lives. And they are telling us, very clearly, that at least some of the time, they would rather work than not!

Jensen, G.D. (1963) Preference for bar pressing over freeloading as a function of number of rewarded presses. Journal of Experimental Psychology, 65, 451–454.


May, D.L. (2004). The vocal repertoire of Grey Parrots (Psittacus erithacus) living in the Congo Basin (Central African Republic, Cameroon). PhD Thesis, University of Arizona, Tucson.

Menzel EW (1991) Chimpanzees (Pan troglodytes)—problem seeking versus the bird-in-hand, least-effort strategy. Primates, 32, 497–508.

McGowan, R.T.S., Robbins, C.T., Alldredge, J.R., Newberry, R.C. (2010) Contrafreeloading in grizzly bears: implications for captive foraging enrichment. Zoo Biology, 29, 484–502.

Neuringer, A.J. (1969). Animals respond for food in the presence of free food. Science, 166, 399-401.

Tarte, R. (1981). Contrafreeloading in humans. Psychological Reports, 49, 859-866.

Irene Pepperberg, Ph.D.

About Irene Pepperberg, Ph.D.

Dr. Irene Pepperberg is an adjunct associate professor at the Dept. of Psychology, Brandeis University, Waltham, MA. She is also a lecturer and research associate at Harvard University, in Cambridge, MA.