Archive for the ‘Neuroscience’ Category

Why your self-interest attracts cooperation? It might be because your are percieved as a decent person.

October 4, 2010 1 comment

Hombre, put a white collar and a spruce tie on. Senorita, fancy up a snappy, classy dress.


Matt Bomer (aka Neal Caffrey in The White Collar Show)

Matt Bomer (aka Neal Caffrey in The White Collar Show)


Are you done grooming? Alright. Lets do business now. But first, let me give you my credentials:

I do business with complete honesty, and I will inform you about all the profits you will earn. There will be no ulterior motives from my part: all my cards will be revealed, so you will know exactly what my next move will be. But here is the thing: in this enterprise that I have, if you seek self-interest while I maintain my honesty, you will win more money and I will get less. On the other hand, if we are both honest, then it’s 50/50 for both of us, which means that you will earn less than from being dishonest. However, there is a third scenario. I might not be as honest as I described myself, so you will once in a while get cozened by me. Eventually, you will find out that I am not at all consistent in my cooperation. Will you still decide to cooperate? Let’s find out.

In a little experiment done by Delago, Frank, and Phelps (2005), they tried to find out the implication of the human striatum in the trial-and-error feedback processing and reward learning. Particularly interesting for them was the caudate nucleus (CN), a structure in the brain that has been linked with memory and processing affective feedback. They hypothesized that the activity in the CN increases during the initial learning process and  could diminish overtime once you learn to interpret the cues from your environment correctly. Hence, CN is presumed to be an important component in guiding future actions.

In order to examine the activity of CN in people who have to make economic choices in social contexts, Delago et al. used a trust game, similar to the business deal I offered you earlier:

In their two-person trust game, 12 participants played with three fictional characters. In the game, participants could either keep the $1 dollar they earn from each trial or give it to their partner, who would actually get $3 instead of $1, and who would then have to make the decision to share the money or not (Fig 1). Additionally, they were presented with lottery trials, in which participants decided whether they wanted to play or not in order to win $1.50  Before the game, however, they were given specific descriptions about each fictional partner. To precis: they were instructed that one fictional partner will be good (“an English graduate student and volunteer inner-city teacher who rescued a friend from a fire during a crowded concert”), and the other two will be bad (“a business graduate student who had been arrested for trying to sell tiles of the space shuttle Columbia on an Internet auction site”) and neutral. Also, subjects were told that their partners’ responses might not always be consistent with the description given at the start of the session. Hence, a good partner might decide to keep the money instead of cooperating. Actually, during the experimental session, each partner had a 50% reinforcement rate, so there was no difference the behavior of the fictional partners.


Figure 1: a trial game was divided into a decision phase and outcome phase and could be played with three possible partners (good, bad, and neutral).


Subjects also were asked to give pre- and post- experimental trust ratings (Fig. 2) for each fictional partner, which were later compared with their overall behavioral choices and neuroimaging results.

Behavioral results:

Delago et. al found that the descriptions did change the initial perceptions of the fictional partners’ trustworthiness that the subjects made, but those perceptions withered by the end of the experimental session, mainly because subjects learned that partners were not always consistent in their response patterns. Here are the pre- and post- experimental trust ratings:


Fig 2: To trust or not to trust...


Participants were generally more likely to share with the good fictional partner than with the bad or neutral partners (Fig. 3), despite the decrease in trust in the good partner. This shows an unexpressed dissonance between the participants’ perception and their behavior. If they notice that between the good, the bad, and the neutral fictional partners there is no difference in the chosen outcomes, then why do they still make more decision to share with the good partner than with the bad?



Fig. 3: Behavioral choices during experimental sessions


Since participants made more decisions to share with the good partners, it is safe to presume that they were affected by the partners’ descriptions of their morality. But what is happening in their brains?

Neuroimaging results:

Functional magnetic resonance imaging (fMRI) data was collected separately for the outcome and decision phases. As it was predicted, for the outcome phase there was a significant increase in activation in the  ventral caudate nucleus, caused by the negative feedback (monetary gain) and positive feedback (monetary loss).


Activity in the ventral portion of the caudate nucleus


The significant activity in the caudate nucleus suggests that the perceived moral character influences the underlying neural activity involved in processing feedback. However, the same activity of the CN was not observed in the decision phase. During the decision phase, activation was observed mainly in the ventral striatum (VS), which suggests that VS might play a role in making predictions and anticipating outcomes.


White Collar Image from here


Delago, M. R., Frank, R. H., Phelps, E. A. (2005). Perceptions of moral character modulate the neural systems of reward during the trust game. Nature Neuroscience, 8(11): 1611-1618.