Intrinsic recreation of moderately uncertain events in macaques

Curiosity drives information-seeking without extrinsic incentives. Prior studies using looking-time measures suggest that curiosity peaks at intermediate uncertainty. Yet developmental and comparative research often reports that increased looking does not necessarily translate into action, leaving open whether animals intrinsically take overt actions generating intermediate uncertainty. Here, we show that monkeys are biased not only to look longer, but also to spontaneously interact with their environment in ways that recreate intermediate uncertainty. In a reward-free, hide-and-seek-like touchscreen game, Japanese macaques (Macaca fuscata) chose between two buttons that produced puppet appearances with different levels of spatial noise: intermediate vs. low (Experiment 1) and vs. high (Experiment 2). When noise variation was perceptible rather than imperceptible, macaques shifted their choice bias toward the intermediate-noise button by 9.6% (Experiment 1) and 13.5% (Experiment 2), and reselected it faster. Such intrinsic tendencies may optimize information gain by promoting engagement with stimuli offering maximal learning opportunities.