Playing Rock-Paper-Scissors against another person can actually make your choices more random than playing against a random-number generator, according to new research. The study, published on arXiv in May 2026 by Song-Ju Kim, Shoma Ohara, and Hiroaki Kurokawa, reveals that human interaction can push our behavior beyond our usual cognitive limits, creating a rare form of high-complexity randomness.
The research
The team analyzed over 100 matches of Rock-Paper-Scissors involving 9 participants, totaling 216 individual move sequences. They used a measure called Lempel-Ziv complexity (LZC) to quantify how random each player's sequence was. When playing against a random (RNG) opponent, the highest LZC score any human achieved was 84. This served as a baseline for typical human randomness.
In human-human matches, most sequences fell below that 84 threshold, but a small number actually exceeded it—creating a "high-complexity tail" that never appeared against a random opponent. To understand why, the researchers developed a "sensitivity" metric: how often a player responds to the opponent's most frequent recent move by choosing the move that beats it. Using statistical models, they found that when a player shows this sensitivity, it predicts an increase in the opponent's future move entropy (randomness), especially when the opponent's moves were already in a low-entropy, biased state.
Circular-shift surrogate analysis confirmed that this effect is interaction-specific: the boost in randomness only happens during live play, not when sequences are artificially scrambled. The findings suggest that human randomness is not just an individual capacity but can be enhanced through social interaction in a state-dependent way.
Why it matters
This study challenges the idea that randomness is a fixed trait. It shows that interacting with another person can destabilize our habitual biases and push us toward more unpredictable behavior. For cognitive training, this implies that practicing against adaptive opponents—rather than static drills—might better improve your ability to generate random sequences, a skill linked to creativity and problem-solving.
What you can do
Try playing strategy games like Rock-Paper-Scissors or chess against a live partner instead of a computer. Notice how your decisions change when you must adapt to another person’s patterns. Over time, this may enhance your cognitive flexibility and ability to break out of rigid thinking.
Source: arXiv q-bio.NC
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