We all have our own preferences on how leisure time — and monkeys do too. White-faced saki monkeys (Pithecia pithecia) in a zoo in Finland were given a choice between “primate-focused” versions of Spotify and Netflix to see what they preferred. After a month of observations, researchers found the monkeys were more likely to ditch screentime and just relax with music.

Enrichment activities, from puzzle feeders to climbing structures, are very important to maintain the physical and mental health of animals in zoos and sanctuaries. Some zoos are even using computer-based, interactive enrichment systems with primates, to offer them the mental stimulation they require. These systems aim to seek to stimulate cognition in ways similar to the activities the animals do in the wild and improve the quality of life for animals.

Specifically, researchers from the University of Glasgow in the UK and Aalto University in Finland wanted to explore how a group of three white-faced saki monkeys would respond to being able to trigger visual or audio stimuli on demand, similar to a primate-focused Spotify or Nexflix. It’s the first kind of system to offer monkeys a choice of stimuli.

“We’ve been working with Korkeasaari Zoo for several years now to learn more about how white-faced sakis might benefit from computer systems designed specifically for them,” Hirskyj-Douglas, a study author, said in a statement. “This is the first time we have given the monkeys the option to choose between audio and video.”

An interactive system

The researchers created a computer interface contained in a special tunnel that they placed in the monkey’s enclosure. The tunnel contained three interactive zones triggered by infrared sensors. When a monkey moved through the infrared beam, it would activate video or sound that played as long as they stayed there.

The researchers used the device for a total of 32 days. During the first week, the tunnel was silent to allow them to adjust to its presence. Then, the monkeys could choose between an audio or video stimulus that changed every few days. These were rain sounds, music of traffic noise, or videos of worms, abstract shapes and colors, and underwater scenes.

Every time the monkeys interacted with the system, it automatically recorded what was playing and the time they spent in the interactive zone. Most interactions were short, lasting just a few seconds each time they walked or ran. During the final seven days of the experiment, the researchers returned the tunnel to being non-interactive.

The sakis were found to trigger audio stimuli twice as much as visual stimuli. As the study progressed, overall levels of interaction with both stimuli dropped, but the interactions with visual stimuli increased compared to audio. Out of the three audio files, they listened to music the most. Underwater scenes were the most popular of the three videos.

“Animal-computer interaction is still an emerging field of research. The data we collected in this study will be part of further developments as we learn more about their habits and preferences. The ultimate goal for us is to bridge the gap between human understanding of how animals access and experience computer systems,” Hirskyj-Douglas said.

The study will be presented at the ACM SIGCHI Conference on Designing Interactive Systems and was not peer-reviewed yet.