Behavioural patterns in social networks

In this paper, we focus on the analysis of individual decision making for the formation of social networks, using experimentally generated data. We first analyse the determinants of the individual demand for links under the assumption of agents' static expectations. The results of this exercise subsequently allow us to identify patterns of behaviour that can be subsumed in three strategies of link formation: 1) reciprocator strategy - players propose links to those from whom they have received link proposals in the previous round; 2) myopic best response strategy - players aim to profit from maximisation; 3) opportunistic strategy - players reciprocate link proposals to those who have the largest number of connections. We find that these strategies explain approximately 76% of the observed choices. We finally estimate a mixture model to highlight the proportion of the population who adopt each of these strategies

Social networks and trust: not the experimental evidence you may expect

We run a laboratory experiment where 'friendship' networks are generated endogenously within an anonymous group. Our experiment builds on two phases in sequence: a network formation game and a trust game. We find that in those sessions where the trust game is played before the network formation game, the overall level of trust is not significantly different from the one observed in a simple trust game; in those sessions where the trust game is played after the network formation game we find that the overall level of trust is significantly lower than in the simple trust game. Hence surprisingly trust does not increase because of 'enforced reciprocity' and moreover a common social history does affect the level of trust, but in a negative manner. Where network effects matter is in the choice of whom to trust: while we tend to trust less on average those with whom we have already interacted compared to total strangers, past history allows us to select whom to trust relatively more than others

Strategies in social network formation

We run a computerised experiment of network formation where all connections are beneficial and only direct links are costly. Players simultaneously submit link proposals; a connection is made only when both players involved agree. We use both simulated and experimentally generated data to test the determinants of individual behaviour in network formation. We find that approximately 40% of the network formation strategies adopted by the experimental subjects can be accounted for as best responses. We test whether subjects follow alternative patterns of behaviour and in particular if they: propose links to those from whom they have received link proposals in the previous round; propose links to those who have the largest number of direct connections. We find that together with best response behaviour, these strategies explain approximately 75% of the observed choices. We estimate individual propensities to adopt each of these strategies, controlling for group effects. Finally we estimate a mixture model to highlight the proportion of each type of decision maker in the population

Elective affinities

We propose a marriage model where assortative matching results in equilibrium for reasons other than those driving similar results in the search and matching literature. A marriage is a joint venture where husband and wife contribute to the couple’s welfare by allocating their time to portfolios of risky activities. Men and women are characterised by different preferences over risk and the optimal match is between partners with the same level of risk aversion. In our model no two men (women) rank the same woman (men) as most desirable. Given that there is no unanimous ranking of candidates, everyone marries in equilibrium their most preferred partne

Elective affinities

2noWe propose a marriage model where assortative matching results in equilibrium for reasons other than those driving similar results in the search and matching literature. A marriage is a joint venture where husband and wife contribute to the couple’.s welfare by allocating their time to portfolios of risky activities. Men and women are characterised by different preferences over risk and the optimal match is between partners with same level of risk aversion. In our model no two men (women) rank the same woman (men) as most desirable. Given that there is no unanimous ranking of candidates, everyone marries in equilibrium their most preferred partner.openopenD. Di Cagno; E. SciubbaDI CAGNO, DANIELA TERESA; E., Sciubb

The better toolbox: experimental methodology in economics and psychology

In experimental economics one can confront a “don’t!”, as in “do not deceive your participants!”, as well as a “do!”, as in “incentivize choice making!”. Neither exists in experimental psychology. Further controversies exist in data collection methods, e.g., play strategy (vector) method in game experiments, and how to guarantee external and internal validity by describing experimental scenarios by feld-related vignettes or by abstract, often formal, rules as it is used in decision and game theory. We emphasize that diferences between the experimental methodology of the two disciplines are minor rather than substantial and suggest that such diferences should be resolved, as much as possible, through empirical research. Rather than focusing on familiar debates, we suggest to substitute the revealed-motive approach in experimental economics by designs whose data not only inform about choice, but also about the reasoning dynamics

Telling the other what one knows? Strategic lying in a modified acquiring-a-company experiment with two-sided private information

Lying for a strategic advantage is to be expected in commercial interactions. But would this be more or less obvious when lying could come from either party and question mutually profitable exchange? To explore this, we modify the acquiring-a-company game (Samuelson and Bazerman in Res Exp Econ 3:105–138, 1985) by letting both, buyer and seller, be privately informed. Specifically, the value of the company for the buyer is known only by the seller; whereas, only the buyer is aware by which proportion the sellers evaluation is lower than that of the buyer. Before bargaining, both parties can reveal what they know via cheap-talk numerical messages. Game theoretically, the pooling equilibrium may or may not allow for trade depending on the commonly known expected evaluation discrepancy. By mutually revealing what one knows, one could boost trade and efficiency. Although strategic misreporting prevails quite generally, it is higher for sellers throughout the experiment. Regarding gender, women misreport less, especially as sellers, and offer higher prices

Trusting versus monitoring: an experiment of endogenous institutional choices

We investigate the problem of deciding between trusting and monitoring, and how this decision affects subsequent behavior, using a laboratory experiment where subjects choose between the Ultimatum and the Yes-No Game. Despite the similarity of the two games in Ultimatum Games responders monitor the allocation proposal, while in Yes-No games responders react without monitoring, i.e. have to rely on trust. We permit either the proposer or responder to make the game choice and analyze how both roles choose between trusting and monitoring, what the ensuing effects of their choices are, and how they vary depending on who has chosen the game. We, also, experimentally vary the cost of monitoring and the responder’s conflict payoff. Since monitoring is usually costly, the amount to share in Yes-No Games (YNG) can exceed that in Ultimatum Games (UG). Regarding the conflict payoff, it can be positive or negative with the former rendering Yes-No interaction a social dilemma. According to our results, proposers (responders) opt for trusting significantly more (less) often than for monitoring. Average offers are higher in Ultimatum than in Yes-No games, but neither UG nor YNG offers depend on who has chosen between games

Trust and trustworthiness in the villain’s dilemma: collaborative dishonesty with conflicting incentives?

Wrong-doers may try to collaborate to achieve greater gains than would be possible alone. Yet potential collaborators face two issues: they need to accurately identify other cheaters and trust that their collaborators do not betray them when the opportunity arises. These concerns may be in tension, since the people who are genuine cheaters could also be the likeliest to be untrustworthy. We formalise this interaction in the “villain’s dilemma” and use it in a laboratory experiment to study three questions: what kind of information helps people to overcome the villain’s dilemma? Does the villain’s dilemma promote or hamper cheating relative to individual settings? Who participates in the villain’s dilemma and who is a trustworthy collaborative cheater? We find that information has important consequences for behaviour in the villain’s dilemma. Public information about actions is important for supporting collaborative dishonesty, while more limited sources of information lead to back-stabbing and poor collaboration. We also find that the level of information, role of the decision maker, and round of the experiment affect whether dishonesty is higher or lower in the villain’s dilemma than in our individual honesty settings. Finally, individual factors are generally unrelated to collaborating but individual dishonesty predicts untrustworthiness as a collaborator

Behavioral spillovers in local public good provision: an experimental study

In a circular neighborhood, each member has a left and a right neighbor with whom(s) he interacts repeatedly. From their two separate endowment amounts individuals can contribute to each of their two structurally independent public goods, either shared only with their left, respectively right, neighbor. If most group members are discrimination averse and conditionally cooperating with their neighbors, this implies intra- as well as inter personal spillovers which link all neighbors. Investigating individual adaptations in one’s two games with differing freeriding incentives confirms, through behavioral spillovers, that both individual contributions anchor on the local public good with the smaller free-riding incentive. Therefore asymmetry in gaining from local public goods allows to establish a higher level of voluntary cooperation