Pet dogs are willing to work for food, but do not show a preference

Recent trends in pet dog feeding blogs have stressed contrafreeloading as a reason to provide enrichment devices to dogs. We show that although dogs are willing to work for food when offered an enrichment feeder and free food simultaneously, they do not show a preference for this behavior.
Pet dogs are willing to work for food, but do not show a preference

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Contrafreeloading refers to the phenomenon that animals will choose to work for food when given the choice between working for their food and similar freely available food (1-3). This behavior has been shown in both domesticated (e.g. pigs (4)) and non-domesticated species (e.g. giraffes (5)).

Recently, a study showed that pet cats do not have a preference to contrafreeload (6). If pet cats do not show this preference, we wanted to find out if dogs, another domesticated companion animal species, show similar behavior to their companion animal counterparts, or to other domesticated species.

To test this, we adopted a community science approach by providing dog owners with a snuffle mat and a plate and asking them to record their dog's behavior when simultaneously offered both feeding options with identical amounts of food. Due to the applied nature of enrichment in dogs, we thought a community science paradigm would allow owners to have an active involvement in understanding their dog's feeding behavior. Since there is also a link between contrafreeloading and exploratory behavior (7), we provided owners with a Fi Smart Dog Collar ( to track activity levels.

Figure 1. An example of a dog eating food from the feeders.

After looking at many options for a snuffle mat, we decided to make our own snuffle mats out of anti-fatigue rubber floor mats. We made this decision based on our desire to have the free food and snuffle mat similar sizes. To make the "snuffle" part of the snuffle mat, we went to the craft store and bought remnants of fleece fabric. We cut the fabric into smaller pieces and wove the fabric through the holes of the fatigue mat to create a feeder that mimics natural foraging behavior. 

Figure 2. The snuffle mat made by the research team out of anti-fatigue mats and fabric.

We invited owners to our lab in Manhattan to meet their dogs and show them how to conduct the study on their own at home. All owners were provided a "goody bag" with all supplies and instructions. As a thank you to the owners, all participants were able to keep the supplies (e.g. snuffle mat, tray and Fi Collar) after the study ended. In order to allow owners to ask us an questions with ease, we created a Facebook group for owners to ask any lingering questions that came up after their lab visit. We also invited owners to introduce their dogs to the group to provide a sense of community.

Once dogs completed the study, owners were sent a certificate of participation. We invited owners to send us photos of their dogs posing with their certificates.

Figure 3. Wilson poses for the camera with his graduation certificate.

We thank all of the dogs and their owners for their participation!


  1. Inglis, I. R., Forkman, B. & Lazarus, J. Free food or earned food? A review and fuzzy model of contrafreeloading. Anim. Behav. 53, 1171–1191 (1997).
  2. Jensen, G. D. Preference for bar pressing over ‘freeloading’ as a function of number of rewarded presses. J. Exp. Psychol. 65, 451–454 (1963).
  3. Osborne, S. R. The free food (contrafreeloading) phenomenon: A review and analysis. Anim. Learn. Behav. 5, 221–235 (1977).
  4. de Jonge, F. H., Tilly, S.-L., Baars, A. M. & Spruijt, B. M. On the rewarding nature of appetitive feeding behaviour in pigs (Sus scrofa): Do domesticated pigs contrafreeload? Appl. Anim. Behav. Sci. 114, 359–372 (2008).
  5. Sasson‐Yenor, J. & Powell, D. M. Assessment of contrafreeloading preferences in giraffe (Giraffa camelopardalis). Zoo Biol. 38, 414–423 (2019).
  6. Delgado, M. M., Han, B. S. G. & Bain, M. J. Domestic cats (Felis catus) prefer freely available food over food that requires effort. Anim. Cogn. (2021). doi:10.1007/s10071-021-01530-3
  7. Bean, Mason, G. J., & Bateson. Contrafreeloading in starlings: Testing the information hypothesis. Behaviour. 136, 1267–1282 (1999).

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Life Sciences > Biological Sciences > Zoology > Animal Science > Ethology

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