New study reveals that incoherent choices are normally part of how the brain assesses options

Economists have noticed that people can behave inconsistently when making choices. According to economic theory, people should choose the same things each time, under the same circumstances, because they have the same value as before. But people do not always do that. Sometimes consumers change their preferences, which the industry calls "customer turnover". Although economists have previously described this error as a rationality error, a new study indicates that a significant portion of inconsistent choices is due to idiosyncratic activity in areas of the brain that value.

"If the value of a Coca-Cola is higher than that of a Pepsi, you should choose Coca-Cola every time," says Ryan Webb, co-author of the study, Assistant Professor at the Rotman School of Management at the University of Toronto. "But because of these" noisy "fluctuations of neuronal activity, Pepsi is getting better than Coca-Cola."

Webb, Vered Kurtz-David and the prof. Dotan Persitz and Dino Levy of Tel Aviv University were able to observe the phenomenon by asking research volunteers to play a series of lotteries while they were inside a resonance imaging scanner functional magnetic (fMRI). The fMRI monitors neuronal activity by detecting changes in blood flow in different parts of the brain.

Volunteers had to choose between different combinations of chips directed at two simultaneous lotteries, each with a 50% chance of being the winner. Each volunteer has played lotteries several times in a row within the fMRI.

FMRI studies have shown that the most active areas of the brain during the most inconsistent choices were the same as those responsible for badessing the value. In other words, the areas of the brain that usually make rational choices sometimes make them irrational as well. This contradicts previous theories that rational and irrational decision-making is influenced by the activity of different parts of the brain or by different thought processes, an idea popularized in the book by Daniel Kahneman, Thinking Fast and Slow.

The results suggest that inconsistent occasional choices are fundamental to the functioning of a typical brain, regardless of the efforts made to ensure that people stick to their usual preferences.

"Sometimes people will choose another product," says Professor Webb, who combines neuroscience, psychology, and economics in his research. "From time to time, they will rock."

The study was published last month in Nature Communications.