Almost exactly four years ago, I wrote a blog entitled “The Work Ethic,” which describes how many individuals, be they human or nonhuman, might—surprisingly—actually prefer to work for rewards rather than receive them for free. The formal term for this behavior is called “contrafreeloading,” and I described a study by some of my colleagues that was presented at a conference. They found that African grey parrots, in particular, would prefer to interact with an experimenter, trading a token for food rather than just taking the food itself.
The work has since been published (Krasheninnikova et al., 2018). It seemed that the parrots viewed the interaction with the experimenter not as “work” but as an added bonus. The study intrigued me because I noted that many Africna greys, my own Athena included, often engaged in a related behavior—that is, they seem to enjoy engaging with various foraging toys, figuring out how the gizmos worked even though they could often obtain the same foods in their dishes without doing anything extra. In the wild, of course, they have to “work” for all their food—crack nuts, eviscerate fruits, and juice bark (May 2004).
These data from the Krasheninnikova et al. paper really intrigued one of my students, and she decided to investigate the behavior for her MA thesis. The student, Gabriella Smith, thought that the key to deciding whether to engage in contrafreeloading was if the activity involved would be considered work or play—that is, something onerous versus something fun to do en route to getting a treat.
After talking over how we would design the experiment, we decided to see if the quality of the treat might also affect the decision to go for free food or engage in the action leading to the food. We hypothesized that if the activity was considered “fun,” our birds would do it whatever the reward, but if it was “work,” they would do it only to get their most favored treats.
Moreover, we wanted to see if they found the activity itself rewarding enough that they would choose it by itself more than a free treat. And, finally, we wanted to test at least two different activities—one “artificial” (something like a foraging toy) and something more “ecological” (something more natural) to see if a difference existed in what they chose to do—i.e., might “work” be innately triggered in some way?
We also recruited a few companion African greys to see how generalizable the behavior might be. So we included Pepper and Franco, who have taken part in several experiments over the years, and Lucci, who belonged to one of my research assistants and who was naïve to any research activities.
Different Birds, Different Preferences
We first had to choose, and then test, for each parrot, a set of three different foods that could be ranked in order of preference. Each bird might have a different set or, within that set, a different order. Once we had the information on food rankings, we could then start the experiments.
The first experiment involved a small container that could have a loosely attached lid that the parrot could flip off to receive a reward. Treats would be placed in covered or uncovered cups; the latter were ‘”free.” The second experiment involved a choice between a nut still in its shell (i.e., one that required some work to obtain) and an already shelled, “free” nut.
In Experiment 1, each bird received 270 trials of container pairs holding more- or less-preferred free or enclosed food items, using each of the different food items. We also tested containers with and without covers to see if lid-flipping was a favored action. And we continued to test their food preferences, to ensure that no change had occurred over the course of the experiment. This last information was important, because we were looking at different degrees of contrafreeloading, which we classified as follows: calculated contrafreeloading (working to access preferred food over less-preferred, freely available food); classic contrafreeloading (working to access food equal in value to freely available food); and super contrafreeloading (working to access a less-preferred food over preferred, freely available food).
In Experiment 2, we put a shelled or unshelled nut in each uncovered container and let the bird choose. They could spend a significant amount of time cracking the shell with their beak, or they could just eat the shelled nut. All we did was mark down their choice.
The results were quite interesting, and although each bird kept their food preferences throughout Experiment 1, in every other way they were quite different (Smith et al., 2021). In Experiment 1, Griffin significantly preferred classic and calculated contrafreeloading and even did some super contrafreeloading; Athena, Pepper, and Franco significantly preferred calculated contrafreeloading; Lucci didn’t participate as he had no interest in the cups at all. In Experiment 2, Athena and Franco surprised us by significantly preferring to crack the shell to obtain the nut (contrafreeloading); Griffin and Lucci did not; Pepper chose at chance.
What was clear was that for Griffin, lid-popping was fun and cracking nutshells was work, but the opposite was true for Athena and Franco. Lucci also thought nutshell cracking was work. Griffin would even pop a lid on an empty container in preference to eating a less favored treat (see Figure)!
It was clear that all four birds in Experiment 1 were willing to work a bit if it meant getting a better reward than the one they could have for free (calculated contrafreeloading). Their behavior wasn’t a matter of age—Griffin, Lucci, and Pepper are about the same age; Franco isn’t very much younger. And Franco is significantly older than Athena. It isn’t a matter of gender, either—Pepper and Athena are both female, whereas Griffin, Franco, and Lucci are male.
The take-home message here is that the kind of task we give our companion animals for enrichment really matters! What one bird might enjoy, another may simply ignore. Each bird will have its own preferences. The point is to keep introducing various types of enrichment—we can’t give up just because our birds might not like what we think would be fun—it has to be fun for them!
References
Krasheninnikova, A., Höner, F., O’Neill, L., Penna, E., & von Bayern, A. M. P. (2018). Economic decision-making in parrots. Scientific Reports, 8(1), Article 12537. https://doi.org/10.1038/s41598-018-30933-5
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.
Smith, G.E., Greene, D., Hartsfield, L.A., & Pepperberg, I.M. (2021). Initial evidence for contrafreeloading in Grey parrots via the opportunity for playful foraging. J. Comp. Psychol. doi: 10.1037/com0000295.