Motivation: The network effect

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New research reveals that the motivation to behave in a socially beneficial way can spread from one individual to another, particularly when they are closely connected. This means that organizations can leverage the impact of actions designed to motivate so-called prosocial behavior by targeting social networks.

4 min read

BruhinAdrian Bruhin is a professor of Economics. He studies in particular the relative importance of different behavioral theories in the fields of decision making under risk and prosocial behavior.

Prosocial behavior, where people voluntarily act in the interest of the common good, is an important part of a well-functioning society. Donating to charity, giving time as a school governor, volunteering to help at a public event, not dropping litter, even voting in elections, it is the myriad everyday acts of public service and good citizenship that help maintain the fabric of a productive and prosperous society. It is no surprise then, that policymakers and other interested parties strive to encourage this type of behavior. Yet, despite the attention given to promoting good citizenship, it is still not clear what policy interventions are most effective.

The motivation to act prosocially may spill over from one person to another in social networks where individuals are linked through social ties

There has been some research on the topic. There is some evidence from existing research, for example, suggesting that people are more likely to behave in a prosocial way if they are aware of others behaving in a similar manner. And that the motivation to act prosocially may spill over from one person to another in social networks where individuals are linked through social ties. If such motivational spillovers of prosocial behavior exist they could greatly enhance the effectiveness of policy interventions, as these interventions would not just affect directly targeted individuals but cascade through to members of their social network.

This is the issue explored by academics Adrian Bruhin, Lorenz Goette, Simon Haenni, and Lingqing Jiang, in their paper “Spillovers of Prosocial Motivation: Evidence from a Randomized Intervention Study on Blood Donors”.

Motivational spillover

The authors examine voluntary blood donations from donors registered with the Blood Transfusion Service of the Red Cross in Zurich, Switzerland and, in particular, donation data for the period April 2011 to January 2013 during which donors were repeatedly invited to blood drives – time limited events to obtain blood. Giving blood is a good example of prosocial behavior; a voluntary act where the donor receives no material reward while bearing the personal cost of giving blood. The authors focus on pairs of donors who are likely to share strong social ties, as they live at the same address and there is no more than 20 years difference in ages between them. About two-thirds of the donor pairs are couples living together, while the rest are other cohabitants, or neighbors living in the same building. This equated to 3,723 donor pairs, with 10,120 observations of donor pairs making donation decisions – 20,240 at the individual donor level.

One significant challenge was isolating the impact of spillovers on the motivation to give blood as opposed to, for example, the impact of environmental factors or personal characteristics that both people in a pair have in common. As it turned out a feature of the data allowed the authors to solve this challenge. A random subset of donors received an additional call to their mobile phone, during office hours, two days before a blood drive, telling them their blood type was in short supply and urging them to donate. Previous research shows that donors receiving such a call are about eight or nine percentage points more likely to donate blood than donors who do not receive such a phone call – this is borne out by the authors’ findings.

The randomized phone call allowed the authors to isolate the effect of motivational spillovers because it only directly impacts the motivation of the person being called and not the motivation of their donor pair. If the person in the donor pair who is not directly affected shows an increase in their probability of donating following that phone call, it can be attributed to motivational spillovers. The authors also verified that it is really the phone call recipient’s motivation to donate that spills over, and not the information about a particular blood type being in short supply.

For every one unit increase in a donor’s motivation, there is a 44 per cent spillover in motivation to their donor pair

While the exact mechanism through which motivational spillover works is not properly understood, the authors found that motivational spillovers play an important role in spreading the motivation to donate blood. For every one unit increase in a donor’s motivation, there is a 44 per cent spillover in motivation to their donor pair. The resulting increase in the fellow donor’s motivation then spills back, resulting in a positive feedback loop. This positive feedback loop creates a social multiplier of 1.79 for any policy motivation that greatly enhances its effectiveness. For example, if a policy intervention manages to increase an individual’s probability of donating by say 10% the aggregate increase in donation rates due to this social multiplier is 17.9%.

Leveraging motivational interventions

The social multiplier effect might extend to other interventions within an organization or society designed to motivate a particular type of behavior

The significance of these findings extends far beyond blood donations. Given that it is the motivation cascading and feeding back from one person to another, it seems feasible that the social multiplier effect might extend to other interventions within an organization or society designed to motivate a particular type of behavior. And, therefore, those interventions would benefit from targeting social groups – project teams, or intra-organizational networks and clubs, for example. Although it is important to note that the authors are not claiming that such spillovers apply beyond prosocial behavior and further research would be required to confirm a comparable social multiplier effect.

For policymakers, what the research highlights for sure is that efforts at encouraging good citizenship, whatever the particular activity they are hoping to boost, should be directed at affecting the motivation of individuals in social groups. Motivational interventions targeted at couples, friends, families, club members, or church congregations, for example, are likely to be more efficient and effective than targeting independent individuals. Harnessing a network effect, by utlizing social ties, policymakers can leverage the motivational impact of policy interventions designed to promote good citizenship.


Read the original research paper: Bruhin A., Goette L., Haenni S. & Jiang L. (2014). Spillovers of Prosocial Motivation: Evidence from a Randomized Intervention Study on Blood Donors (14.10). University of Lausanne – HEC – DEEP.


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