Playing rock-paper-scissors makes humans more random

When people play rock-paper-scissors against other humans rather than a computer RNG, a small fraction produce move sequences more complex than any seen against the machine. The key mechanism: when one player notices the opponent leaning on a favorite move and exploits it, the opponent is nudged out of that rut, boosting unpredictability. Randomness, it turns out, isn't just a fixed individual trait—it can be socially contagious.