The classic “rock, paper or scissors” sleight of hand, which is used to randomly decide who will do something unappetizing, is not based on the random choice of three possibilities, but rather there is a pattern of behavior. Players choose conditioned by the result of the immediately previous game , making their move predictable and providing a winning advantage to their rival. This is the conclusion of a recent mathematical study, whose objective was to inquire about the influence of human psychology in a recreational activity based, theoretically, on luck.
Of oriental origin and inspired by the fighting techniques of martial arts, the popular game consists of three options, rock, paper and scissors, which win and are beaten mutually, so that all of them have the same probability of being chosen in each round (one third). For this reason and according to classical game theory, players would win by assigning their options completely at random, in order to be unpredictable and that their rivals cannot anticipate their movements, a pattern known as the Nash equilibrium. The scientists sensed, however, that underlying the mechanics of the game were patterns of behavior, since the human brain does not manage to act with absolute randomness.
To clarify this, the researchers, belonging to the University of Zhejiang (China), called a competition in which 360 individuals participated, also encouraged by a monetary reward proportional to the number of victories. The results of the observation showed a tendency to repeat the winning plays, and to change the losing plays following the name of the game (rock-paper-scissors) as a pattern . Thus, when players rolled “stone” and won, they rolled “stone” again in subsequent rounds more frequently than would be randomly expected. In the opposite case, in which they took “stone” and lost, they used to opt for the “paper” in the successive rounds. This game strategy has been called “conditioned response”.
In view of the results, to be victorious it would be enough to avoid this pattern. In other words, if we are able to overcome the need to repeat a play in case of winning and change it each time it is lost, we will be able to disconcert our rival and win on a greater number of occasions. The question now is whether this formula is extensible to the “lizard” and “Spock” modes.
