Resisting the urge to order takeout instead of reheating leftovers takes inhibitory control—the ability to suppress an impulse in favor of a better option. Humans aren’t the only animals with this skill, and experiments have shown that many species can resist impulses to varying degrees. Now, for the first time, a team led by psychologists Sydney Hope and Joshua Plotnik of City University of New York has used a classic psychology experiment to show that Asian elephants (Elephas maximus) can resist their impulses to get food in a more effective way. Their results were published in the journal PLOS One.
Testing Elephants with the Detour Paradigm
The researchers collaborated with a team at the Golden Triangle Asian Elephant Foundation in Thailand, where 16 Asian elephants aged 4 to 60 years were tested using the detour paradigm. In this classic psychological test, a subject is presented with a goal—in this case, tasty fruit—but a barrier blocks the path of least resistance. To reach the goal, the subject must take an alternate route, acting against their immediate impulse.
For the elephants, the fruit was placed inside a transparent box. Before the test trials, the elephants had been familiarized with reaching into a black box for food. The transparent barrier was likely a new experience: as far as the researchers knew, the animals had no prior experience with transparent materials.
What the Elephants Had to Do
The elephants could see and smell the fruit through small, impenetrable holes in the front of the box, but they couldn’t reach it directly. If they reached around to another face of the box, however, they found an opening through which they could grab the fruit with their trunks—just as they had learned with the black box.
“The test trials should have been more difficult because, to reach the food reward, elephants needed to inhibit the impulse to reach straight toward the food that they could see and smell in front of them and, instead, continue to detour around the box in the way that they had learned during the familiarization trials,” the researchers explain in their paper.
All attempts were captured on camera and analyzed in detail: how long it took each elephant to touch the box, find the open side, grab the food, and so on.
Strong Inhibitory Control, with Curiosity
“When faced with a transparent surface after being trained to detour around an opaque barrier (i.e., the ‘knowing/acting mismatch’), elephants did not show any difference in latency to enter the opening, and continued to quickly detour around the transparent barrier,” the authors report. “This may provide evidence that elephants exhibit very strong inhibitory control; however, it may also indicate that the transparent surface did not elicit a strong prepotent response.”
In other words, the elephants didn’t seem to be fooled by the transparent barrier. But once their trunks were inside the perspex box, they spent more time exploring its interior, displaying curiosity about the see-through material.
Adapting to a Changed Box
The researchers also turned the box around so that the opening was on a different face than the elephants were used to. This adjustment delayed the elephants’ search for food, though they ultimately still figured it out.
“This ‘characteristic error pattern’ of a slower latency to enter suggests that switching box orientations evoked a prepotent response, making it a valid measure of inhibitory control,” the authors report.
They also noticed that older elephants had a harder time adapting to the changes, which could be a signal of waning cognitive function.
A Starting Point for Understanding Elephant Cognition
The study is far from conclusive on elephant intelligence, but it’s a start. Animals capable of this kind of impulse control tend to have more complex social lives, something elephants certainly depend on.
“The evidence for strong inhibitory control in Asian elephants that we found in this study agrees with the general positive relationship between brain size and inhibitory control ability that is found across other taxa,” the authors conclude.
The research was published in PLOS One.
