Carrot-and-stick works in the US but not in Romania

Recently, an anonymous peer reviewer of one of my papers brought to my attention an exciting cross-cultural study on cooperation, rewards, and punishment. The study was conducted with US and Romanian students who were asked to repeatedly play:

  • public good games (PGGs)
  • versions of Prisoner’s Dilemma (PD)
  • PGGs followed by PDs
  • PGGs followed by punishment opportunity.

The main findings are:

  1. US and Romanian students did not differ in their cooperation measured by repeated PGGs and PDs.
  2. However, when given an opportunity to reward (through PD) or punish the behaviour of others, students from the two countries differed considerably:
    • American students frequently rewarded cooperation and withheld rewards towards non-cooperators.
    • Romanian students tended to reward those who rewarded them previously, but rewards were not linked to group-benefitting cooperation. In other words, Romanian students valued the prosperity and success within pairs more than within group (This finding suggests that reputation-building may not be a cooperation-enhancing mechanism in all environments/cultures.)
  3. When presented with an opportunity to punish, American students used punishment mostly to enforce cooperation, whereas Romanian students displayed high levels of antisocial punishment. Punishment meted out by Romanian students was often indiscriminate: targeted against both non-cooperators and cooperators.

I liked the study a lot but was not convinced by the high-level interpretation of the findings. The authors say: “Broadly speaking, we suggest that some societies prosper because they are good at building shared understanding.” and “The ultimate reason that an engaged group member is able to foster cooperation is that the other group members understand what is going on and adjust their behavior both with respect to the group at large and with respect to the engaged group member.” How do the above results address the problem of shared understanding? Didn’t Romanian students understand what was “going on” and adjust their behaviour in response to how others behaved? Although they didn’t foster cooperation, the strategy they adopted might have been better suited to the socio-environmental conditions they live in.

Ellingsen, Tore, Herrmann, Benedikt, Nowak, Martin A., Rand, David G. and Tarnita, Corina E., Civic Capital in Two Cultures: The Nature of Cooperation in Romania and USA (November 1, 2012). Available at SSRN: or