Rock Paper Scissors Tells: Evidence and Testing

Reading Tells in Rock Paper Scissors

A “tell” is a proposed observable cue that predicts a throw before the valid reveal. WRPSA found no primary evidence supporting universal finger, wrist, face, breathing, or voice rules of the kind previously listed here. One controlled face-to-face study reported automatic gesture imitation, but that result does not validate those specific tells or establish a prediction for every match. Define a cue before observing the outcome, keep it separate from an illegal late reveal, and measure its later hit and miss rate.

A cue is a hypothesis. Record it before the reveal and count every miss.

By Wyatt Baldwin, founder of WRPSAUpdated September 13, 2026

What Would Count as a Tell?

A tell is a cue observed before the valid reveal that predicts the opponent’s later gesture better than a stated baseline. The cue, observation window, predicted gesture, comparison, and scoring rule must be defined before the outcome is known.

Cook et al. reported automatic imitation in a controlled sighted-versus-blindfolded RPS setup. That result concerns visual-motor compatibility under its protocol; it does not show that a wrist angle, gaze, breath, voice, or facial movement reliably identifies an intended throw. Treat each proposed cue as a new test and keep the strategy baseline visible.

A Prospective Test

Use a simple preregistered procedure before relying on any cue:

Define it: Write the exact visible cue, its observation window, and the one gesture it predicts before play begins.
Separate timing: A cue must occur before the valid simultaneous reveal. Seeing a forming hand and responding late is a rules violation, not skill.
Score it: Count every prediction, hit, miss, draw, and unscorable round; compare later observations with an equal or empirical-frequency baseline.

Keep the Reveal Fair and Consistent

Consistent mechanics reduce accidental information and make simultaneous play easier to judge:

Use the published cadence and reveal on the same beat.
Keep the hand in the required neutral position before the reveal.
Use one clear, accessible final gesture and hold it long enough to adjudicate.
Do not change a decision after seeing the opponent’s forming or completed hand.
If a physical limitation affects a gesture, agree on the accessible equivalent before play.

Is This Even Legal?

Observing conduct within the event rules is different from delaying a throw to gain information. The match remains valid only when both players reveal under the same timing rule.

A response made after seeing the opponent’s forming or completed gesture is a late throw, not a tell read. See the official rules. Deliberate statements or cues are governed by the event’s conduct rules and are discussed cautiously in the bluffing guide.