Have you ever stopped to think about the motive that leads us to distrust certain people and instantly trust others – even if we do not know any of them?
A study done in the United States has investigated this and concluded that it is all a question of how the learning system of our brain works .
It is that, according to the authors, our perception of a stranger’s reputation, even without having any direct information about him, is based on his physical resemblance to people we know. In other words, we tend to distrust those who look like acquaintances whom we consider dishonest or immoral – and we tend to rely more on strangers who look like people we trust.
“And that happens even if we are not aware of this resemblance,” explains one of the authors, Professor Elizabeth Phelps of the psychology department at New York University (NYU). “It shows that our brains implement a learning mechanism in which moral information encoded from past experiences guide future choices, ” he adds.
To reach this conclusion, tests based on trust games were conducted. In them, volunteers should decide whether or not to share money with other players (which were fictitious and represented by facial images).
In each game, the person had to decide whether to entrust their money to three different players. In the first round, she learns that everything she shares would be multiplied by four and that the other player could repay that amount or keep all the money for herself.
Each fictitious player could be highly trusted (they shared the money 93% of the time), more or less trustworthy (shared 60% of the time) or unreliable (they shared only 7% of the time).
In a second round, volunteers should select new partners for the game – this time new players. But there was a secret trick: the researchers had created the face of these new participants from the image of the previous ones. That is, they were similar to the other players in the first round.
Most of the time, even without realizing the similarity, the volunteers eventually chose those who looked like the most honest players of the previous round and avoided playing with those who resembled the least reliable. The more resemblance to trusted players than before, the greater the confidence shown in them, and vice versa.
To sum up, the researchers analyzed the volunteers ‘brain activity as they made their decisions in the game, and concluded something interesting: in deciding whether or not the strangers could be trusted, the volunteers’ brains activated the same neurological regions from when they learned about the partner in the first task. This includes the amygdala, a region that plays an important role in emotional learning.
The study was published in the journal Proceedings of the National Academy of Sciences .