This academic paper, “Oxytocin Increases Generosity in Humans,” details the study of the effect on material generosity from greater-than-normal doses of a hormone in a small sample of test subjects. The game used during the experiment is a variation of the money-splitting game we considered as part of our exploration of network exchange theory.

In the study, Paul Zak of Claremont Graduate University started with 68 male participants (women were not included since increased doses of oxytocin raise the risk of miscarriage) and gave half of them oxytocin (OT) by nasal inhaler. The other half were given a saline solution as a placebo. Paired randomly, each subject was identified only by a number and separated from his partner (no talking was allowed). In the first trial, one of each pair of each pair received $10 and was required to offer a portion to his partner. If the partner accepted, they would divide and keep the money. If the second partner rejected the offer, they would both walk away empty-handed. Before learning what role he would play, each subject was asked about his preferred actions for both positions. This made each put himself in his partner’s shoes before beginning. In the second trial, the same partners were paired; however, this time, the second subject had to accept what he was offered. All players knew the nature of the game and were playing for real cash.

The OT had no effect on the minimum offer a subject was willing to accept for either trial–it was $2.97 on average, regardless of OT or placebo. However, when it came to giving, the OT made a significant difference. During the first trial, those who inhaled OT offered an average of $4.86, while those who received saline offered an average of $4.03. When recipients had to accept the offer regardless of their personal preference, in the second trial, offers were $3.68 on average with little difference between OT and placebo users. We see that giving is reduced when the giver does not explicitly consider the receiver’s reaction.

This is interesting to consider for a number of reasons. First, it highlights the way in which unconscious biological processes (ie, the release of hormones) or the simulation of such (eg, inhaling the hormone) can lead to altered social behavior. Second, it is interesting that the receiving subject would sometimes refuse the offer. We discussed this possibility when working out the balance of power and end-results with the money-splitting game was played with different nodal configurations. Third, we can see the demonstration of power in this small, two-person network during the second trial, when reject was removed as a choice. Since the receiver had no other options, the giver was in a more powerful position than before.

It is worth pointing out that Zak recalls mice without OT receptors exhibit signs of social amnesia, lacking social memory and engaging in atypical social behavioral patterns. Zak said in an interview with Discover Magazine, “All kinds of daily transactions require that people spend just a little bit of their time and resources to help someone out. I think society as we know it couldn’t exist without that.” Indeed, he may be correct, as figures for charitable giving continue to rise and philanthropic foundations have an increasing impact on the world. Some see the current trend in giving, especially by the super-empowered wealthy and visible elite like Bill Gates, Larry Page, and Sergey Brin, as the beginning of a cascade of contributions. We can only hope that the prosperous among us respond either to the signals they are receiving or the actions of their peers in a way that leaves us all better off.

Note: I originally came across news of this paper while reading the “Raw Data” section (entitled “The Generosity Hormone” by Jennifer Barone) from Discover Magazine’s April 2008 issue.