Capra & Rilling: Social Decision-Making

Monica Capra & Jim Rilling
Social Decision-Making

This second lunch of the center was about neuroscientific and economic perspectives of social decision making. And since such decisions always involve risks, I am taking one myself. A neophyte blogger, I used the previous blog to report to you about the first lunch meeting. It generated zero (0!) comments. Why? With insightful feedback from Laura Namy (Psychology), I think that maybe I should be more personal -- shorter on the reporting and longer on my own impressions and thoughts. That’s what I will try today. I will briefly introduce the speakers, summarize their main ideas, and share some responses from the participants. Then I will use the blogger license and share some of my own thoughts.

The effect of social information on consuming decisions

In a highly interdisciplinary spirit, Monica Capra (Economics) introduced the new discipline of neuroeconomics -- a field that draws on neuroscience to study economics. Neurological data are important because many of our decision processes are hidden. While behaviorally we can detect the overt, the neurological allows us to peek into the covert. Her own studies explore the effect of social information on consuming decisions. She found that individual adolescents who originally selected a certain song as their favorite, changed their choice to what was revealed to them as the most popular song. This was true for 80% of the trials where popularity information was given, compared with only 40% of the trials lacking popularity information. Brain activation when switching from the original song to the most popular one, was primarily on one area -- the insula. The activation of the insula, which is related to the visceral, was interpreted by Monica as a “mismatch anxiety.” Jim Rilling (Anthropology) in addition emphasized Damasio’s claim that the insula participates in decision making.

In return to be informed by neuroscience, economics provides neurological studies with theoretical framework within which to interpret the neurological data. And indeed this is the framework within which Jim described his own work. He has been peeking into people’s brains for quite a few years. As an anthropologist, Jim is motivated by his desire to understand the evolution of human social behavior and the human brain, and by the understanding that life is NOT a zero-sum game -- my gain is not necessarily your loss. We can have a win-win game, but this usually requires cooperation, which can be fragile. As a species, we excel in cooperation, and its neurology is one of the areas that Rilling’s lab explores.

The effects of vasopressin on the amygdala in a trust game

Informed by game theory (a mathematical theory used in economics to describe decisions under strategic interdependency), and studies of neuropeptides (peptides found in neural tissues), Jim’s lab studies the effects of oxytocin and vasopressin on the activation of the amygdala, which responds to danger and threats. These effects are studied during decision making in a trust game that involves the exchange of money.

The person in the scanner is either playing with another person, who is in a separate room, or with a computer. He can cooperate or not. The immediate profit in each iteration can be increased by non-cooperation but a greater success for each player is highly probable if both partners cooperate. The hormonal effect is studied by administering oxytocin, known to increase trust and attachment, or by contrast vasopressin, known to increase anxiety, to the person in the scanner.

In a study of Ernst Fehr’s lab, oxytocin, as hypothesized, suppressed activation of a “distrusting” amygdala during decision making. By contrast, the vasopressin effect, which is studied in Jim’s lab, is more complicated. In the role of the first mover, vasopressin-treated subjects showed increased amygdala activation. But the more times the subject chose to cooperate, the less the amygdala was activated. In the role of the second mover, vasopressin-treated subjects were more likely than placebo subjects to reciprocate cooperation by the first mover. Several interpretations were offered. Monica spoke of other studies that distinguish between reciprocity and generosity. Jim proposed that social anxiety, induced by the vasopressin, might help in sustaining mutually cooperative relationships.

The give-and-take between economics and neuroscience was beautifully demonstrated by Monica and Jim, even though their interpretations of brain-activation data were somewhat different. This might be partly because neuroeconomics is still in a “baby-steps” phase, as was pointed by Monica.

Methodological issues

Jim pointed to a methodological difference between the economical and anthropological studies. While most economic studies keep the partner player anonymous by design, anthropological studies question the ecological validity of such a practice. Jim feels that for ecological validity, it is important for the player to meet the other player. His comment might be informed by his own studies that show effects of the other player’s behavior on that of the scanned person only when the game is against a human but not against a computer.

The question of ecological validity applies, I believe, to the anthropological studies as well. While the goal of Jim’s studies is to explore cooperation in games, the amounts involved are small and therefore the motivation of the participant might be questioned. I recently learned about a possible way around it from Jan Engelman, a post doc in psychiatry, who studies the neurobiological effects of expert messages on the process of risky decision making, with Monica. They use the experimental currency of Yen, which is not the real Japanese currency but is “inspired” by it. The exchange rate is around 1:100, so the numbers are big, and one is likely to not get involved in their conversion to American dollars during the study itself. Ecological validity restored, the experimenters hope (An idea for a study about what accounts for greater ecological validity?).

A neuroethical remark

Paul Lennard (Neuroscience & Behavioral Biology) spoke on behalf of neuroethics, questioning the very practice of peeking into people’s brains, possibly violating privacy. He also questioned the possible abuse of the findings of such studies to increase commercial profit. What if we nasally spray people with oxytocin before they see a certain ad? Without disagreeing with such dangers, Jim responded with the possible positive outcomes of his studies. Maybe the autistic population, with its naturally low oxytocin, can be helped with administered oxytocin to increase their ability to cooperate socially.

The big game of money

As for me, money -- the main lubricant of modern economics -- is fascinating since the day on which I realized that it is a game. As such, Jim’s studies are relevant. I used to have a software house in Wall Street. I started my days at 5:30 am and took a breakfast break at around 7:00. That early in the morning-- just before it comes to its full activity -- the Street, which runs gently downhill from Broadway to the East River, looks like a human river itself. It is dense with people, typically well dressed, rushing to their offices, touching each other since they are so many, and creating a colorful and dynamic scene. The people’s faces, however, mirror the Dow Jones. I realized it on one morning, walking to my breakfast, facing this human river with all its faces pointing down. I realized that money is like Lewis Carroll’s Queen of Hearts. We people invented a card game, and to the puzzlement of Alice, the queen of the cards started beheading us. Obviously, this card game was more about people than about cards. And so is the biggest human game in history – money.

That it would get reified and have so much power over us is likely related to the forces underlying culture in general; often without our awareness. Monica’s studies of conformism might help us understand some of these forces. And Jim’s understanding of cooperation might contribute to underlying their mechanisms.

Hope to hear from you,
Shlomit