Learning about early warning signals and the structure of collaborations with a large-scale experiment on Reddit

For three days in April 2022, 10 million Reddit users placed colored pixels on a giant canvas, at a maximum per-user rate of one pixel every five minutes. This game-experiment "r/place" is a great window into human collective behavior, as users needed to collaborate to build significant "compositions" (i.e. discernible drawings). We studied the transitions in these compositions (i.e. their replacement by another drawing), which could provide general insights on transitions in socio-ecological systems. To build a warning system for these transitions, we use gradient-boosted decision trees to combine multiple time-dependent variables in each composition. The resulting early warning signals predict half of the transitions coming within 20 minutes (6 hours) with only 0.5% (14%) false positives, which improves highly on considering a single time series and on more standard signals such as variance and autocorrelation of a state variable. The 2023 edition of r/place serves as an ultimate test that the warning system is efficient even considering inter-year variability. This massive experiment teaches us new ways to foresee transitions is socio-ecological systems, while shedding light on the optimal structures of collaborations, as we can correlate the type of network of users of a composition to its resilience.