Wired for risk

This was an interesting article sent to me courtesy of a reader, "Economic decision-making in psychopathy": A comparison with ventromedial prefrontal lesion patients," featuring our good friend Newman as one of the authors. The gist of the article is that "born" sociopaths share certain risking taking and economic decision-making patterns in common with people who have an impaired ventromedial prefrontal cortex, the part of the brain that is associated with risk, fear, and decision-making.

First, the researchers make a distinction between classes of sociopaths:

“primary” (low-anxious) psychopathy is viewed as a direct consequence of some core intrinsic deficit, whereas “secondary” (high-anxious) psychopathy is viewed as an indirect consequence of environmental factors or other psychopathology. 

Next, the sociopaths were given two classic decision-making tasks, the Ultimatum Game and the Dictator Game. Regarding the Ultimatum Game:

In the Ultimatum Game, two players are given an opportunity to split a sum of money. One player (the proposer) offers a portion of the money to the second player (the responder), and keeps the remainder for himself. The responder can either accept the offer (in which case both players split the money as proposed) or reject the offer (in which case both players get nothing). “Rational actor” models predict that the responder would accept any offer, no matter how low. However, relatively small offers (less than 20–30% of the total) are rejected about half the time (Bolton and Zwick, 1995; Guth et al., 1982). The “irrational” rejection of unfair offers has been correlated with feelings of anger (Pillutla and Murnighan, 1996), suggesting that the responder’s ability to regulate anger and frustration plays a critical role in task performance. Patients with vmPFC lesions, who are known to exhibit irritability and poor frustration tolerance despite an otherwise generally blunted affect (Anderson et al., 2006; Barrash et al., 2000), reject an abnormally high proportion of unfair offers (Koenigs and Tranel, 2007). Thus the first aim of this study is to determine whether either of the psychopathic subtypes (primary or secondary) also rejects an abnormally high proportion of unfair offers.

And the Dictator Game:

In the Dictator Game, there are again two players with an opportunity to split a sum of money. However, in this case the responder has no choice but to accept whatever split the proposer offers. Thus, the amount offered by the proposer in the Dictator Game is presumed to reflect a prosocial sentiment, such as empathy or guilt. Patients with vmPFC lesions, who are known to exhibit deficits in empathy and guilt (Anderson et al., 2006; Barrash et al., 2000), offer abnormally low amounts in the Dictator Game (Krajbich et al., 2009). Thus the second aim of this study is whether either of the psychopathic subtypes (primary or secondary) also offers abnormally low amounts in the Dictator Game.

I'm not surprised at all by the results. The only thing I find somewhat puzzling is that the primary and secondary sociopaths differ. I would think that both types would try to shortsell their partners in the games. Unless the secondary sociopaths are a little bit more aware or paranoid that this may be a situation that would leave them vulnerable to the unpredictable social judgment of others?