A team of scientists, led by the American mathematician Percy Deacconis, recently conducted an unusual experiment that challenges the traditional concept of randomness in decision-making. The researchers observed 350,757 coin tosses involving coins of different currencies and discovered a surprising pattern that raises doubts about the true randomness of the process.
While many people believe that the chances of a coin landing on heads or tails are equal, the study revealed that in 50.8% of cases, the coin actually lands on the same side that was facing up before the toss. This phenomenon, termed “the effect of the initial side,” is attributed to subtle fluctuations in the coin as it travels through the air.
During the experiment, 48 volunteers threw coins from 46 different currencies. Analysis of the data collected showed that the “initial side effect” manifested differently in each participant, suggesting that individual throwing techniques may influence the outcome. A mathematical model developed by Deaconis’ group further explained that the coin remains upright for a longer period during its rotation in the air.
The researchers were even honored with the Shnobel Prize, which recognizes the most unconventional or absurd scientific achievements. To illustrate the practical implications of their discovery, the scientists provided an example from the realm of gambling. By placing $1000 bets on coin toss results while knowing the initial position of the coin, one could potentially earn around $19, surpassing the advantage that a casino holds in certain games like Blackjack.
Although the slight advantage gained from the “initial side effect” may not compare to the odds favoring a casino in European roulette, the findings highlight how even minor deviations from randomness can significantly impact decision outcomes. To address this issue in decision-making scenarios, the researchers suggest concealing the initial side of the coin before the toss to eliminate potential bias. The full results of the study are available on the ARXIV preprint server.