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Cooperation in Large Networks: an Experimental Approach (with C.Jaramillo)
We present a new design of a simple public goods experiment with a large number of players, where up to 80 people in a computer lab have the possibility to connect with others in the room to induce more cooperators to contribute to the public good and overcome the social dilemma. This experimental design explores the possibility of social networks to be used and institutional devices to create the same behavioral responses we observe with small groups (e.g. commitments, social norms, reciprocity, trust, shame, guilt) that seem to induce cooperative behavior in the private provision of public goods. The results of our experiment suggest that the structure of the network affects not only the players’ ability to communicate, but their willingness to do so as well. Finally, we find that the local connectivity structure of the network has an important role as determinant of the willingness of the players to engage in a more costly type of collective action, namely the endogenous creation of new links to individuals previously out of reach.
Keywords: Social capital, social networks, collective action, cooperation, VCM, experiments, public goods provision. JEL Classification: C92, D7, D85, H41. 1
Gender, education and reciprocal generosity: Evidence from 1,500 experiment subjects (with P.Branas & M.Rossi)
gender.pdf 405,68 kB
Pablo BrañasGarza, Universidad de Granada (Spain)
Juan C. Cárdenas, Universidad de los Andes (Colombia)
Máximo Rossi, Universidad de la República (Uruguay)
There is not general consensus about if women are more or less generous than men. Although the number of papers supporting more generous females is a bit larger than the opposed it is not possible to establish any definitive and systematic gender bias. This paper provides new evidence on this topic using a unique experimental dataset. We used data from a field experiment conducted under identical conditions (and monetary payoffs) in 6 Latin American cities, Bogotá, Buenos Aires, Caracas, Lima, Montevideo and San José. Our dataset amounted to 3,107 experimental subjects who played the Trust Game. We will analyze the determinants of behavior of second movers, that is, what determines reciprocal generosity. In sharp contrast to previous papers we found that males are more generous than females. In the light of this result, we carried out a systematic analysis of individual features (income, education, age, etc.) for females and males separately. We found differential motivations for women and men. Third, we see that (individual) education enhances pro‐social behavior. Lastly, we see that subjects’ expectations are crucial.
Keywords: Reciprocal altruism, gender, education
COLLECTIVE ACTION FOR WATERSHED MANAGEMENT: FIELD EXPERIMENTS IN COLOMBIA AND KENYA (with L.A.Rodriguez and N.Johnson) Published, Environment and Development Economics
Forthcoming, Environmental and Development Economics
The dilemma of collective action around water use and management involves solving both the problems of provision and appropriation. Cooperation in the provision can be affected by the rival nature of the appropriation and the asymmetries in the access. We report two field experiments conducted in Colombia and Kenya. The Irrigation Game was used to explore the provision and appropriation decisions under asymmetric or sequential appropriation, complemented with a Voluntary Contribution Mechanism experiment which looks at provision decisions under symmetric appropriation. The overall results were consistent with the patterns of previous studies: the zero contribution hypotheses is rejected whereas the most effective institution to increase cooperation was face-to-face communication, and above external regulations, although we find that communication works much more effectively in Colombia. We also find that the asymmetric appropriation did reduce cooperation, though the magnitude of the social loss and the effectiveness of alternative institutional options varied across sites.
Social norms and behavior in the local commons through the lens of field experiments (Published, Environment and Resource Economics)
Behavior in the local commons is usually embedded in a context of regulations and social norms that the group of users face. Such norms and rules affect how individuals value material and non-material incentives and therefore determine their decision to cooperate or over extract the resources from the common-pool. This paper discusses the importance of social norms in shaping behavior in the commons through the lens of experiments, and in particular experiments conducted in the field with people that usually face these social dilemmas in their daily life. Through a large sample of experimental sessions with around one thousand people between villagers and students, I test some hypothesis about behavior in the commons when regulations and social norms constrain the choices of people. The results suggest that people evaluate several components of the intrinsic and material motivations in their decision to cooperate. While responding in the expected direction to a imperfectly monitored fine on over extraction, the expected cost of the regulation is not a sufficient explanatory factor for the changes in behavior by the participants in the experiments. Even with zero cost of violations, people can respond positively to an external regulator that issues a normative statement about a rule that is aimed at solving the social dilemma.
Risk Pooling, Risk Preferences, and Social Networks (with O.Attanasio, A.Barr, G.Genicot and C.Meghir)
Using data from a feld experiment conducted in seventy Colombian municipalities, we investigate who pools risk with whom when risk pooling arrangements are not formally enforced. We explore the roles played by risk attitudes and network connections both theoretically and empirically. We and that pairs of participants who share a bond of friendship or kinship are more likely to (1) join the same risk pooling group and to (2) group assortatively with respect to risk attitudes. Also, consistent with our theoretical ¯nding that when there is a problem of trust the process of pooling assortatively with respect to risk preferences is perturbed, we and (3) only weak evidence of such assorting among unfamiliar individuals.
It’s Not My Money: An Experiment on Risk Aversion and the HouseMoney Effect
The house‐money effect –people’s tendency to be more daring with easily‐gotten money– is a behavioral pattern that poses questions about the external validity of experiments in economics: to what extent do people behave in experiments like they would have in a real‐life situation, given that they play with easily‐gotten house money? We ran an economic experiment with 66 students to measure the house‐money effect on their risk preferences. They received an amount of money with which they made risky decisions involving losses and gains; a treatment group got the money 21 days in advance and a control group got it the day of the experiment. We find that, when facing possible losses, people in the treatment group showed a lower tolerance to risk than people in the control group. If the players are assumed to have a CRRA utility function and to behave according to expected‐utility theory, the risk‐attitude adjustment corresponds to an average increase of 1 in their risk aversion coefficient. While the exact pattern of this house‐money adjustment differs by gender, it is not possible to determine the sign of this gender effect unambiguously. In any case, it is advisable to include credible controls for the house‐money effect in experimental work in economics.
Key Words: House‐money effect, risk aversion, prospect theory, experiment JEL Code: C91, D03, D81
Social Preferences Among the People of Sanquianga in Colombia
Este paper hace parte del proyecto de raices de la sociabilidad humana
En el que se hicieron experimentos sobre comportamiento pro-social en 16 sociedades de pequeña escala en varios continentes del mundo.
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Resource Allocation in Public Agencies: Evidence from a Field Experiment (with R.Sethi)
Many organizations, including philanthropies and public agencies, require their employees to make resource allocation decisions that are intended to serve a broad social purpose or mission.In most cases the criteria on the basis of which scarce funds are to be allocated are imprecisely specified, leaving agents with considerable discretionary power. This paper reports results from a set of field experiment that explores the manner in which such power is exercised. Using a sample of public servants working in education, health, child care and nutrition programs in Colombia,and a sample of potential and actual bene.ciaries of such programs, we attempt to identify the set of recipient attributes that induce the most generous responses from o¢ cials. This is done using a design we call the "distributive dictator game" which requires officials to rank recipients, with the understanding that a higher ranking corresponds to an increased likelihood of getting a voucher convertible into cash. Interpreting the ranking as the outcome of a random utility model, we estimate the effects of recipient attributes using a rank-order logistic regression. We find that public officials tend to favor women, married persons, individuals with many minor dependents, and refugees from political violence.
Bringing the Lab to the Field: More than Changing Subjects
This paper discusses why running experiments in the field, outside of the university lab, can help us enrich the analysis we do of experimental data. One of the main arguments of the paper is that people participating in experiments, including students, do not come naked to the lab. They bring a great deal of rules of thumb, heuristics, values, prejudices, expectations and knowledge about the others participating, and about similar games, and use such information to make their decisions.
Discrimination in the provision of social services to the poor: a field experimental study (with N.Candelo, S.Polania, A.Gaviria, and R.Sethi)
Experimentos sobre pro-socialidad entre funcionarios publicos y grupos vulnerables en Bogota.