Behaviors associated with mental illness can be picked up on by a healthy person playing an online strategy game with someone they’ve never met.
A team of researchers at the Virginia Tech Carilion Research Institute found that healthy people and those with borderline personality disorder displayed different patterns of behavior while playing the game. In fact, when healthy players played people with borderline personality disorder, they simply gave up trying to predict their partner’s next move.
For the study, scientists used a multiround social interaction game — the investor-trustee game — to study the level of strategic thinking in 195 pairs of subjects.
In each pair, one player played the investor and the other the trustee. The investor decided how much money to give the trustee, and the trustee then decided how much to return to the investor. Profit required the cooperation of both players.
“This classic tit-for-tat game allows us to probe people’s responses to the social gestures of others,” said Read Montague, Ph.D., director of the Human Neuroimaging Laboratory at the Virginia Tech Carilion Research Institute.
“It further allows us to see how people form models of one another. These insights are important for understanding a range of mental illnesses, as the ability to infer other people’s intentions is an essential component of healthy cognition.”
First, the researchers classified the investors according to varying levels of strategic depth of thought. The healthy subjects fell into three categories:
- about half simply responded to the amount the other player sent;
- about one-quarter built a model of their partner’s behavior;
- the remaining quarter considered not just their model of their partner, but also their partner’s models of them.
Not surprisingly, the players who looked deeper into their interactions made much more money than those who played at a shallow level. However, when healthy subjects were paired with people with borderline personality disorder, they were far less likely to exhibit depth of thought.
“People with borderline personality disorder are characterized by their unstable relationships, and when they play this game, they tend to break cooperation,” said Montague.
“The healthy subjects picked up on the erratic behavior, likely without even realizing it, and far fewer played strategically.”
In fact, functional magnetic resonance imaging of the participants’ brains revealed that each category of player showed distinct signals associated with differing depths of thought.
“We’re always modeling other people, and our brains have a substantial amount of neural tissue devoted to pondering our interactions with other people,” Montague said.
“The exquisite sensitivity that most people have to social gestures gives us a valuable opening,” Montague said.
“We’re hoping to invent a tool — almost a human inkblot test — for identifying and characterizing mental disorders in which social interactions go awry.”
Source: Virginia Tech