By Dr. Lisa P. Barrett

The floating object task is a puzzle that comparative cognition researchers present to animals (including humans) to study the evolution of cognitive abilities, like cause and effect understanding and the ability to use water as a tool. To solve the task and retrieve the floating reward inside, you must add water to a tube to raise the water level and reach the reward. Some primates, like orangutans have been able to solve the task by carrying water in their mouths from a drinker and spitting it into the tube to reach a peanut.

My colleague, Dr. Sarah Benson-Amram, and I presented this puzzle to elephants for the first time (Barrett & Benson-Amram, 2020). We wanted to see if elephants’ unique trunk morphology would make them well-equipped for the floating object task. Since they spray water for bathing, and hold water in their trunk as a vessel for bringing it to their mouth, we predicted that they would be up for the task. We collaborated with the National Zoo and the Oklahoma City Zoo to carry out this research. We used a tube filled about 1/3 of the way with water, baited with a floating marshmallow. As is often the case with animal research, things did not go as we expected.

As we began testing the elephants, we found that they were unable to solve the task on their own, except for one elephant at the National Zoo named Shanthi. You can see video of Shanthi solving here. So, we converted the study into a social learning experiment where Shanthi served as a demonstrator for the other elephants (the observers) at the National Zoo.

At the Oklahoma City Zoo, one elephant named Chandra was clicker-trained by keepers to solve the task. The keepers used behaviors Chandra already knew for saline trunk washes, like “suck” and “blow,” to help her learn to add water to the tube and to reach the marshmallow. Chandra then began solving the task on her own and served as a demonstrator for observer elephants (video here).

Compared to naïve (control) elephants who did not receive a demonstration on how to solve the task, observer elephants spent more time interacting with the task after seeing a demonstration at the Oklahoma City Zoo. This could be because observer elephants were related to Chandra, the demonstrator, and were more attuned to her behavior, or because the herd dynamics were somehow different at this Zoo.

No other elephants besides Shanthi and Chandra (the original solvers/demonstrators) solved the task. It is possible that three trials were not enough time for the elephants to figure out the puzzle. It’s also possible that the observers were not paying attention to the demonstrator, or needed more than three demonstrations to pick up the solution themselves.

It is interesting to consider how Shanthi solved the task. She began adding water to the tube in her very first trial but did not fully solve until her second trial. Thus, we cannot conclude she learned via insight learning (i.e., an “a-ha moment”), but rather likely learned through trial-and-error learning. Anecdotally, Shanthi was known to add water to enrichment items, and so it is possible she had an affinity for this behavior. For this reason, we recommend that future studies conduct an initial control trial that involves presenting the animal with an empty tube—just to see if they will add water to the tube no matter if there is a reward inside of it or not. We are also investigating the effect of individual variation, including personality, on problem-solving ability in elephants. Finally, future research will be needed to determine elephants’ level of understanding of the task.

We found that at least one Asian elephant is capable of using water as a tool to solve the problem. We encourage more work with other non-primate, non-avian species in order to better understand the evolution of cognition in animals.

This type of cognitive research has implications for captive elephant welfare and management, as well as wild elephant conservation. Asian elephants are endangered in part because of conflict with humans when they raid farmland, and cognition could play a role in terms of which individuals raid and how successful they are in raiding.

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References

Barrett, L.P. & Benson-Amram, S. (2020). Can Asian elephants use water as a tool in the floating object task? Animal Behavior and Cognition, 7(3), 310-326. doi: https://doi.org/ 10.26451/abc.07.03.04.2020