Russian scientists reveal betrayal or friendship could depend on fleeting glance

MOSCOW, May 11. /TASS/ Scientists from Skoltech, Tomsk State University (TSU), and the University of Oregon have revealed new correlations between eye movements and making decisions. During the course of the research, the behavior of people placed in a model situation from the game theory, known as the "prisoner's dilemma" were recorded and the results have been published in the journal PLoS One.

The investigation has demonstrated that the way a subject’s glance may shift strongly differs depending on the game’s situation. Moreover, the way players are acquainted with one another increases the temptation to cooperate.

"Our results not only bear witness to the complexity of the decision-making process," coauthor of the study and Ph.D. student at Skoltech Tatiana Babkina said, "but they also show the prospects of using systems of tracking eye movements in group experiments to study such events."

What is the ‘prisoner's dilemma’?

The great majority of economic theories rely on the idea that a person always tends to maximize profit but in real life the situation might be quite different. One of the most prominent examples of this is the "prisoner's dilemma", a model task from the game theory. Here, two suspects are accused of a crime, which they in fact did commit. Both of them simultaneously and independently have to choose between two options: blame and betray their accomplice, or cooperate and stay silent.

If both players say nothing, they both get a minimum penalty of 1 year in prison, if both betray each other, each of them serves 2 years in prison. If one betrays the other, but the second keeps silent, the first will be set free while the second will serve 3 years.

The particular details of the game can slightly vary but from a mathematical viewpoint, the optimal strategy in the majority of cases would be betrayal. However, people inherently are living social beings and tend to cooperate that is why players’ behavior may deviate from the optimal strategy.

Tracking glances experiment

In the previous studies, it has been clarified that unacquainted players cooperate and keep mutually silent only in about 20% of the test cases while with recurring game players this number approaches zero. But even a short social interaction of players significantly increases the level of cooperation among strangers moving it closer to that of the ‘friends’ group. In the new study, the scientists aimed at revealing the mechanisms responsible for these changes.

To perform the experiments, they made use of a mobile eye-tracking system and recorded the directions of glances by players involved in the "prisoner's dilemma" game. At the beginning, all participants were not acquainted but right after the first test series, they were introduced to each other.

The whole study was organized not in the framework of a prison surrounding but as a mathematical game with the following rules: if both participants kept silent, they both got 5 points, if both of them "betrayed the other," they both got 1 point, and if one of them "betrayed" the accomplice while the second "kept silent", then the ‘betrayer’ got 10 points while the ‘betrayed silent player’ got zero. At every step of the experiment, the player had to choose an option of either "keeping silent" or "betrayal" by clicking the mouse.

Before the experiment, all participants did not know each other and in the first test run, they mostly opted for the non-cooperative behavior pattern, that is they pressed "betray" button. With this, their eyes were shiftier and on average most often settled specifically on the non-cooperative option.

The situation changed after the participants were introduced to each other. The players started to opt for the cooperative variant and the features of glance movements changed as well. In this case, the glance moved between alternatives of action even more often but stayed fixed for shorter periods of time.