Michael Restivo

Field experiments of success-breeds-success dynamics

Significance Social scientists have long debated why similar individuals often experience drastically different degrees of success. Some scholars have suggested such inequality merely reflects hard-to-observe personal differences in ability. Others have proposed that one fortunate success may trigger another, thus producing arbitrary differentiation. We conducted randomized experiments through intervention in live social systems to test for success-breeds-success dynamics. Results show that different kinds of success (money, quality ratings, awards, and endorsements) when bestowed upon arbitrarily selected recipients all produced significant improvements in subsequent rates of success as compared with the control group of nonrecipients. However, greater amounts of initial success failed to produce much greater subsequent success, suggesting limits to the distortionary effects of social feedback. Seemingly similar individuals often experience drastically different success trajectories, with some repeatedly failing and others consistently succeeding. One explanation is preexisting variability along unobserved fitness dimensions that is revealed gradually through differential achievement. Alternatively, positive feedback operating on arbitrary initial advantages may increasingly set apart winners from losers, producing runaway inequality. To identify social feedback in human reward systems, we conducted randomized experiments by intervening in live social environments across the domains of funding, status, endorsement, and reputation. In each system we consistently found that early success bestowed upon arbitrarily selected recipients produced significant improvements in subsequent rates of success compared with the control group of nonrecipients. However, success exhibited decreasing marginal returns, with larger initial advantages failing to produce much further differentiation. These findings suggest a lesser degree of vulnerability of reward systems to incidental or fabricated advantages and a more modest role for cumulative advantage in the explanation of social inequality than previously thought.

Experimental Study of Informal Rewards in Peer Production

We test the effects of informal rewards in online peer production. Using a randomized, experimental design, we assigned editing awards or “barnstars” to a subset of the 1% most productive Wikipedia contributors. Comparison with the control group shows that receiving a barnstar increases productivity by 60% and makes contributors six times more likely to receive additional barnstars from other community members, revealing that informal rewards significantly impact individual effort.

No praise without effort: experimental evidence on how rewards affect Wikipedia's contributor community

The successful provision of public goods through mass volunteering over the Internet poses a puzzle to classic social science theories of human cooperation. A solution suggested by recent studies proposes that informal rewards (e.g. a thumbs-up, a badge, an editing award, etc.) can motivate participants by raising their status in the community, which acts as a select incentive to continue contributing. Indeed, a recent study of Wikipedia found that receiving a reward had a large positive effect on the subsequent contribution levels of highly-active contributors. While these findings are suggestive, they only pertained to already highly-active contributors. Can informal rewards also serve as a mechanism to increase participation among less-active contributors by initiating a virtuous cycle of work and reward? We conduct a field experiment on the online encyclopedia Wikipedia in which we bestowed rewards to randomly selected editors of varying productivity levels. Analysis of post-treatment activity shows that despite greater room for less-active contributors to increase their productive efforts, rewards yielded increases in work only among already highly-productive editors. On the other hand, rewards were associated with lower retention of less-active contributors. These findings suggest that the incentive structure in peer production is broadly meritocratic, as highly-active contributors accumulate the most rewards. However, this may also contribute to the divide between the stable core of highly-prodigious producers and a peripheral population of less-active contributors with shorter volunteer tenures.

The World Bank, contradictory lending, and forests: A cross-national analysis of organized hypocrisy:

This article draws on the theory of organized hypocrisy to test the hypothesis that World Bank lending in different sectors has contradictory impacts on forests. The authors use ordinary least squares regression to analyze newly available satellite imagery data on forest loss from 2001 to 2014 for a sample of 89 low and middle income nations. The analysis finds support for the theory of organized hypocrisy. The results indicate that World Bank structural adjustment lending and investment lending in the agriculture and forestry sectors are related to more forest loss but World Bank investment lending in the environmental sector is related to less forest loss. The article concludes with a discussion of the theoretical, methodological, and policy implications.

Water, Sanitation, and Health in Sub‑Saharan Africa: A Cross-national Analysis of Maternal and Neo-natal Mortality

We examine the impact of access to an improved water source and sanitation facility on maternal and neo-natal mortality. We analyze data from a sample of 32 Sub-Saharan African nations from 1990 to 2005 using a two-way fixed effects regression model. We find that access to both improved water and sanitation facilities are associated with decreased maternal and neo-natal mortality. We also consider other structural barriers or facilitators of good reproductive health and find that International Monetary Fund structural adjustment, gross domestic product per capita, female educational attainment, and conflict intensity are related to maternal and neo-natal mortality. We conclude by talking about the theoretical implications, methodological implications, policy suggestions, and directions for future research.