By now, most of you have seen announcements of the recent paper showing that Oxytocin increased the level of trusting behavior in an experimental setting. The aspect of these results that I want to
focus on isn’t the medical implications, or the possibilities for abuse or for clinical use, but the fact that economics experiments are being accepted as the standard measuring tool for social behavior in a medical context. Three of the four authors of the paper are economists, judging from their affiliations. The results were published as a letter in Nature.

The economists used a couple of fairly standard game designs that measure trusting behavior in an interaction. The first of two experimental subjects can choose to trust the second, even though there are no later interactions that give the first player an ability to reward or punish the second player’s behavior.

The authors went to a lot of trouble to design an experiment (read the paper!) that distinguished between the trusting behavior of the first players and the trustworthiness of the second. Only the former was enhanced. They then add a variant in which the second role is played by a computer. The first players were more trusting of people under the influence of Oxytocin than without it, but their play when a computers was making the second decision was unaffected by Oxytocin.

The experimenters administered questionnaires to determine whether it was the subjects’ expectations about the outcomes rather than their level of trust that was affected by the Oxytocin. The subjects had indistinguishable expectations about how much they would get by trusting, but still the subjects trusted more under the influence of Oxytocin.

All the news reports I’ve read accept the experimenters terminology, and write as if they agree that what is being measured is indeed trust. This is the first case I can think of in which a medical intervention had effects on interpersonal behavior that matched the kinds of behavior that experimental economists have been probing for a while. I’m impressed by the level of acceptance of economic experiments as measures of something as evanescent as trust. That’s a level of respect I don’t remember seeing before.

Thanks to Ben Sittler for the initial pointer, and the hint that this was relevant to my interests.