Capuchin monkeys learn to ‘kiss’ an AI touchscreen for banana rewards in a groundbreaking Costa Rica experiment as new technology takes animal cognition research into the wild

Wild capuchin monkeys are stepping into the world of artificial intelligence and they are learning the technology surprisingly fast. In a forest reserve in Costa Rica, researchers have developed an AI-powered touchscreen system that allows wild monkeys to complete simple tasks in exchange for banana rewards, according to New York Times.

The technology, called CapuchinAI, could give scientists a completely different and fresh way to study animal intelligence, learning, memory and decision-making in the environment where wild primates actually live. The research was published in The American Journal of Primatology and was developed by scientists from Emory University and the Georgia Institute of Technology.

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Wild monkeys meet AI in the Costa Rica forest

The experiment took place at the Taboga Forest Reserve in northeastern Costa Rica, where researchers study wild white-faced capuchins. CapuchinAI combines facial recognition, a touchscreen, a small computer and an automated food dispenser. When a monkey approaches the platform, the system can detect it, present a task and deliver a food reward when the monkey completes the required action.

The entire setup was designed to work outdoors and can operate for about eight hours on a lightweight battery pack. Researchers said the technology could eventually make it possible to conduct controlled cognitive experiments on wild primates at a much larger scale.

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The monkeys had to learn one simple trick

The first challenge was getting the capuchins to understand what the touchscreen was for and how it worked. Researchers initially placed a blue square on the screen and when a monkey touched the display, the system recorded the interaction and released a piece of dried banana.

For the first two days, the monkeys showed little interest. Then came Trompudo, a large male capuchin whose name means "big snout."

“He climbs on the box and starts slapping the back of it,” researcher Federico Sánchez Vargas recalled. “Finally, he slaps the touchscreen and a banana slice pops out.”

“He was almost like you could see him realising, 'Ah, that's what you have to do, touch the screen!'” Sánchez Vargas said. “It was amazing to watch an individual learn something so quickly.” Soon, other capuchins began approaching the machine.

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Some monkeys learned faster than others

The researchers observed 16 wild capuchins interacting with the prototype, and their reactions were far from identical. Some animals figured out the touchscreen almost immediately while others took their own sweet time to understand how the machine worked.

Some cautious monkeys watched their companions before approaching the device themselves. And then there were monkeys that found their own unusual method of getting the reward.

Researchers observed monkeys using their lips to interact with the screen and effectively “kissing” the touchscreen to make a banana slice appear.

AI can recognize monkeys with 97% accuracy

CapuchinAI's facial-recognition system was initially trained using videos and still images of six wild capuchins. Researchers used thousands of images to teach the system to distinguish individual monkeys.

During field testing, the facial-recognition model identified the six monkeys with 97% accuracy from still images, video and live footage.

But the researchers quickly encountered a problem. There are roughly 100 capuchins at the Costa Rica field site, and the team did not have enough high-quality footage of every individual to train the system.

So, instead of initially requiring the AI to identify exactly which monkey was standing in front of it, the system was trained to recognize whether the approaching animal was a capuchin.

Once a monkey approached the touchscreen, the webcam could record it. Those new recordings could then be used to expand and improve the facial-recognition database.

The AI could eventually test memory and impulse control

The researchers are now developing more sophisticated experiments using CapuchinAI. The planned cognitive tests will examine several areas, including:

• Learning ability
• Impulse control
• Cognitive flexibility
• Short-term memory
• Long-term memory

If the system recognizes a monkey that has already participated in the research, it can present a task appropriate to that individual's stage in the testing sequence.

A monkey that has never used the platform can first receive a simple habituation task: touch the screen and receive a reward.

Why studying wild monkeys matters

Marcela Benítez, an Emory assistant professor of anthropology and senior author of the study, said the project is designed to address that gap.

“The primate brain didn't evolve in a lab, it evolved in complex, competitive environments,” Benítez said. “Yet primate cognition is rarely studied in the wild because the experimental control needed to measure cognition is difficult in unpredictable environments.”

That is where CapuchinAI could become particularly valuable. The project also builds on the work of renowned primatologist Frans de Waal, who spent decades studying animal intelligence, emotions and social behavior.

Sánchez Vargas said the new technology could build on de Waal's emphasis on understanding animals as individuals. “This project builds on the legacy of Frans de Waal,” he said.

Sánchez Vargas said de Waal “gave us intimate, beautiful portraits of the lives of primates, treating them as individuals.”

“Our AI method allows us to more deeply understand individuals that we already have data on through field observation. We can now automate cognitive testing of them and quantify the findings. It's a way of getting into the minds behind the personalities. Studying individuals in their natural environments, where there are tons of variations in their life experiences, lets us learn how environmental influences shaped them.”

A small machine could change how scientists study animals

One of the most striking aspects of the project is how simple the prototype is. The researchers built the weatherproof housing themselves, using materials including pine planks, deck sealant, rubber insulating strips and plastic piping. The system contains a webcam, touchscreen, Raspberry Pi computer, food dispenser and rotary motor.

The resulting box is only around 20 inches (51 centimetres) tall.

Yet the researchers believe a system this compact could eventually enable large-scale cognitive research without capturing or relocating wild animals.

The technology also has safeguards. CapuchinAI can limit the number of food rewards an individual receives during a session, helping prevent a dominant monkey from monopolizing the platform.

AI could reveal why some monkeys are smarter at certain tasks

The researchers are now training the facial-recognition model using videos recorded during the pilot study. Scientists want to investigate individual differences in cognition.

Why does one monkey learn a task faster than another? Why might one animal show stronger impulse control? How do monkeys adapt when circumstances change? And could different cognitive strategies affect an animal's ability to survive and reproduce?

Benítez said the technology could help answer those questions.

“We can explore outstanding questions about how the environment, individual experiences and behaviours connect to cognitive abilities,” Benítez said. “Why are some individuals better at some tasks than others? How do different individuals adapt to different situations? How do different cognitive strategies relate to fitness?”

She described CapuchinAI as “a powerful new tool in the primatology toolkit.”