Rock-paper-scissors is a fun game that is played by people of all ages and nationalities. But there is also a species of lizards that plays this game, albeit in a rather strange way.
Male common side-blotched lizards, also known as Uta stansburiana, have a mating strategy based on the game, where the chances of “winning” is equal and one type has an advantage over another type while being disadvantaged against another type. The males come in three types, differing in the colour of their necks: orange, blue and yellow.
Orange-throated males are the strongest but do not like to form a bond with the female (i.e. do not want a relationship). They can easily win over a fight against the blue-throated males to win the female, but yellow-throated males can sneak in and win over the female instead. Orange beats blue but loses against yellow.
Blue-throated males are middle-sized but do form strong bonds with females. They lose in a fight against orange-throated males, but can easily defend against yellow-throated males as they are always with their female. Blue beats yellow but loses against orange.
Yellow-throated males are smallest but can mimic females, letting them approach females near orange-throated males. They mate with the females while the orange-throated male is distracted, but this strategy does not work with blue-throated males as they have stronger bonds with the females. Yellow beats orange but loses against blue.
Interestingly, although the proportion of the three types average out to be similar over the long run (much like the probability of a person playing a certain hand), in the short term the preferred strategy tends to fluctuate. For example, orange-throated males may strive with their masculine strength for four or five years, but then the trend will slowly switch to yellow-throated males and their mimicking, female-stealing strategy. After another four or five years, blue-throated males will make a comeback as they win over females with their strong bonding.
Rock-paper-scissors is a game with a long history. The earliest example of the game is a Chinese game called huoquan, which follows a cyclic rule where the frog eats the slug, the slug dissolves the snake and the snake eats the frog. The reason why rock-paper-scissors has been saved throughout history is because of the uncertainty it contains. Any hand you choose, the chance of winning is the same. Ergo, there is no single best choice and there is no move that will always win. But this is still a game played by people. It is not a game played by emotionless machines, meaning that you can use human psychology, the surfacing of emotion and specific signs and movements to help deduce your opponent’s hand. Mentalist Derren Brown can read tiny flickering of muscles in the opponent and microexpressions to pull off his “undefeatable rock-paper-scissors trick”, but this is near impossible for a normal person to try. However, you can use the following strategies to improve your odds.
Use paper on a beginner: Statistically, people prefer using rock. Males especially have a strong tendency to play rock.
Use scissors on an experienced player: People who know the first trick can be defeated by going one step further.
Use a hand that loses to the hand your opponent played: This uses the psychology of the opponent wanting to mix up hands and wanting to beat the hand you last played (which is the same as theirs as you drew).
Say what you will play and play that hand: In a competitive situation like rock-paper-scissors, people tend not to trust others. Thus, if you say you will play a certain hand, they will think is a trap and not play the hand that defeats that hand. For example, if you said you will play scissors, the opponent will play paper or scissors and you will either win or draw.
Do not give the opponent a chance to think: People have a subconscious tendency to play a hand that beats the hand that they played before. Without time to think, the subconscious takes action meaning that you can predict their move. If you do the same as strategy 3 and play a hand that loses against the opponent’s previous hand, you will win.
Suggest a certain hand: This is a form of hypnosis where you suggest something to the opponent’s subconscious. To use this trick, pretend to go over the rules by saying “rock, paper, scissors” then play a certain hand. The opponent will likely play the hand that the subconscious last saw.
If you keep drawing, use paper: This is the same as strategy 1.
Unfortunately, rock-paper-scissors has an equal probability of a win and a draw, meaning draws are rather common. Thus, a computer engineer called Samuel Kass devised a game where two additional hands are added: rock-paper-scissors-lizard-Spock. Lizard is played by making your hand into the shape of an animal’s head, while Spock is played using the Vulcan Salute from the science fiction show Star Trek, where you make a V-shape with two fingers on each side. The rules are as follows.
Scissors cut paper. Paper covers rock. Rock crushes lizard. Lizard poisons Spock. Spock smashes scissors. Scissors decapitate lizard. Lizard eats paper. Paper disproves Spock. Spock vaporizes rock. Rock crushes scissors.
As each hand has two ways of winning, the odds of winning is 10/25, or 2/5 and the odds of drawing is 5/25, or 1/5. As you can see, you have double the chance of winning compared to drawing, making the game much faster to play than the original game.