Maria Bigoni

Time Horizon and Cooperation in Continuous Time

When subjects interact in continuous time, their ability to cooperate may dramatically increase. In an experiment, we study the impact of different time horizons on cooperation in (quasi) continuous time prisoners dilemmas. We find that cooperation levels are similar or higher when the horizon is deterministic rather than stochastic. Moreover, a deterministic duration generates different aggregate patterns and individual strategies than a stochastic one. For instance, under a deterministic horizon subjects show high initial cooperation and a strong end-of-period reversal to defection. Moreover, they do not learn to apply backward induction but to postpone defection closer to the end.

Fines, Leniency and Rewards in Antitrust: An Experiment

This paper reports results from an experiment studying how fines, leniency programs and reward schemes for whistleblowers affect cartel formation and prices. Antitrust without leniency reduces cartel formation, but increases cartel prices: subjects use costly fines as (altruistic) punishments. Leniency further increases deterrence, but stabilizes surviving cartels: subjects appear to anticipate harsher times after defections as leniency reduces recidivism and lowers post-conviction prices. With rewards, cartels are reported systematically and prices finally fall. If a ringleader is excluded from leniency, deterrence is unaffected but prices grow. Differences between treatments in Stockholm and Rome suggest culture may affect optimal law enforcement.

Money and Trust Among Strangers

What makes money essential for the functioning of modern society? Through an experiment, we present evidence for the existence of a relevant behavioral dimension in addition to the standard theoretical arguments. Subjects faced repeated opportunities to help an anonymous counterpart who changed over time. Cooperation required trusting that help given to a stranger today would be returned by a stranger in the future. Cooperation levels declined when going from small to large groups of strangers, even if monitoring and payoffs from cooperation were invariant to group size. We then introduced intrinsically worthless tokens. Tokens endogenously became money: subjects took to reward help with a token and to demand a token in exchange for help. Subjects trusted that strangers would return help for a token. Cooperation levels remained stable as the groups grew larger. In all conditions, full cooperation was possible through a social norm of decentralized enforcement, without using tokens. This turned out to be especially demanding in large groups. Lack of trust among strangers thus made money behaviorally essential. To explain these results, we developed an evolutionary model. When behavior in society is heterogeneous, cooperation collapses without tokens. In contrast, the use of tokens makes cooperation evolutionarily stable.

Cooperative Strategies in Anonymous Economies: An Experiment

We study cooperation in economies of indefinite duration. Participants faced a sequence of prisonerʼs dilemmas with anonymous opponents. We identify and characterize the strategies employed at the individual level. We report that (i) grim trigger does not describe well individual play and there is wide heterogeneity in strategies; (ii) systematic defection does not crowd-out systematic cooperation; (iii) coordination on cooperative strategies does not improve with experience. We discuss alternative methodologies and implications for theory.

Amoral Familism, Social Capital, or Trust? The Behavioural Foundations of the Italian North-South Divide

We present the first laboratory‐in‐the field experiment on the Italian North–South divide. Using a representative sample of the population, we measure whether regional disparities in ability to cooperate emerge even if differences in geography, institutions and criminal intrusion are silenced. We report that a behavioural gap in cooperation exists: Northern and Southern citizens react differently to the same incentives. Moreover, this gap cannot be accounted for by tolerance for risk, proxies of social capital and ‘amoral familism’. At least a share of North–South disparities is likely to derive from persistent differences in social norms.

Communication, commitment, and deception in social dilemmas: experimental evidence

Social norms of cooperation are studied under several forms of communication. In an experiment, strangers could make public statements before playing a prisoner’s dilemma. The interaction was repeated indefinitely, which generated multiple equilibria. Communication could be used as a tool to either signal intentions to coordinate on Pareto-superior outcomes, to deceive others, or to credibly commit to actions. Some forms of communication did not promote the incidence of efficient Nash play, and sometimes reduced it. Surprisingly, cooperation suffered when subjects could publicly commit to actions.

Sticks and Carrots in Procurement: an experimental exploration.

Abstract We test the robustness of recent findings on the benefits of penalty contracts to the environments typical of B2B (and B2G) procurement, where buyers and sellers interact repeatedly, matching is endogenous and competitive, there are contractible and non-contractible tasks, and reputation-based relationships can emerge. Both bonuses and penalties boost efficiency, strongly increasing effort in the contractible task while only mildly crowding it out in the non-contractible one. However, sellers grab a higher fraction of surplus with bonuses, as buyers’ offers become more generous. Consequently, buyers prefer penalties, which may explain why they are so widespread in procurement.

EXPERIMENTAL MARKETS WITH FRICTIONS

Decentralized and impersonal exchange is fundamental to contemporary economies, where many interactions take place among individuals with low levels of information about their counterpart. We review the experimental literature about markets with frictions, where strangers interact in pairs formed at random in economies of indefinite duration. We focus on the impact of communication on the efficiency of the outcome and report results of a new experiment.

Money is more than memory

Impersonal exchange is the hallmark of an advanced society. One key institution for impersonal exchange is money, which economic theory considers just a primitive arrangement for monitoring past conduct in society. If so, then a public record of past actions — or memory — supersedes the function performed by money. This intriguing theoretical postulate remains untested. In an experiment, we show that the suggested functional equality between money and memory does not translate into an empirical equivalence. Monetary systems perform a richer set of functions than just revealing past behaviors, which proves to be crucial in promoting large-scale cooperation.

Teams or Tournaments? A Field Experiment on Cooperation and Competition in Academic Achievement

This paper assesses the effect of two stylized and antithetic non-monetary incentive schemes on students’ effort. We collect data from a field experiment where incentives are exogenously imposed, performance is monitored and individual characteristics are observed. Students are randomly assigned to a tournament scheme that fosters competition between coupled students, a cooperative scheme that promotes information sharing and collaboration between students and a control treatment in which students can neither compete, nor cooperate. In line with theoretical predictions, we find that competition induces higher effort with respect to cooperation and cooperation does not increase effort with respect to the baseline. However, this is true only for men, while women do not seem to react to non-monetary incentives.