Gaming monkeys' curiosity

Kyoto, Japan -- The intrinsic information-seeking impulse we call curiosity is independent of extrinsic rewards, such as food or mating opportunities. Curiosity is purely the pursuit of understanding the unknown, driving both humans and animals to explore their environments. Still, certain stimuli tend to spark curiosity more than others.

Recent research supports a Goldilocks principle, in which curiosity is biased toward moderately complex or uncertain stimuli while avoiding overly simple or convoluted situations. This tendency characterizes human curiosity, but few studies have explored this impulse in nonhuman animals. A team of researchers at Kyoto University's Institute for the Evolutionary Origins of Human Behavior, EHUB, wondered if a new sort of method might be useful in addressing curiosity in monkeys.

Video games are gaining more acceptance as tools that may help train cognitive abilities, and thus improve quality of life for humans. The researchers thought that if they could develop a video game that sparked the curiosity and engagement of animals in laboratories and zoos -- or even pets such as cats and dogs -- this could potentially help improve living environments and contribute to animal welfare.

"I originally studied play behavior in wild monkeys, so I have long wanted to create situations in the laboratory where monkeys' play behavior could emerge naturally," says first author Sakumi Iki.

The team investigated what kind of stimuli would elicit the curiosity of resident Japanese macaques at EHUB, and developed a touchscreen-based game task inspired by hide-and-seek. In this game, when a monkey presses a button on the touchscreen, a puppet appears at a different location on the screen, depending on the button. The puppet appearances also correspond to different levels of spatial noise, with puppets appearing in a less predictable location the higher the noise level. While the macaques engaged with the game, the researchers observed their responses to medium versus low noise, then medium versus high noise.

The results revealed that the monkeys tended to choose the medium noise button, which made the puppet appear in a location that was somewhat predictable but still moderately uncertain. These findings suggest that, like humans, macaques have a cognitive tendency to actively explore stimuli with a moderate level of uncertainty, as opposed to stimuli that are either too simple or too random.

The amount of time the monkeys spent playing the game also supports the game's success in sparking their curiosity. "In typical cognitive tasks, monkeys are usually given food rewards to keep them motivated, so I was not very confident they would engage with the game without rewards," says Iki. "Yet surprisingly, some monkeys worked on this game for nearly 100 trials even without any reward."

Next, the team would like to examine whether macaques experience positive emotions while playing these games, and hope to apply these findings to the development of more game tasks that attract the monkeys' curiosity.

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The paper "Intrinsic recreation of moderately uncertain events in macaques" appeared on 18 April 2026 in iScience, with doi: 10.1016/j.isci.2026.115820

About Kyoto University

Kyoto University is one of Japan and Asia's premier research institutions, founded in 1897 and responsible for producing numerous Nobel laureates and winners of other prestigious international prizes. A broad curriculum across the arts and sciences at undergraduate and graduate levels complements several research centers, facilities, and offices around Japan and the world. For more information, please see: http://www.kyoto-u.ac.jp/en