Building Up Social Capital in a Changing World: A Network Approach

This paper models the dynamic process through which a large society may succeed in building up its “social capital” by establishing a stable and dense pattern of interaction among its members. In the model, agents interact according to a collection of infinitely repeated Prisoner’s Dilemmas played on the current social network. This network not only specifies the playing partners but, crucially, also determines how relevant strategic information diffuses or new cooperation opportunities are found. Over time, the underlying payoffs randomly change, i.e. display some “volatility”, which leads agents to react by creating new links and removing others. The process is ergodic, so we use numerical simulations to “compute” its long-run invariant behavior and obtain the following conclusions: (a) Only if payoff volatility is not too high can the society sustain a dense social network. (b) The social architecture endogenously responds to increased volatility by becoming more cohesive. (c) Network-based strategic effects are an essential buffer that preclude the abrupt collapse of the social network in the face of growing volatility. These conclusions, largely in tune with those of the social-capital literature, are further studied analytically in a companion paper through the use of mean-field techniques.Social Capital, Prisoner's Dilemma, Search, Social Networks, Volatility

Network Organizations

It is common to define a network organization as one that is fast and flexible in adapting to changes in the underlying environment. But besides the short-run advantages of adaptability, fast changes in the structure of the organization can also be detrimental in the longer run. This happens, in particular, because agents need to depend widely on that structure to channel appropriately (and thus speed up) search. I discuss the trade-off between adaptability and structural stability in a changing environment where, if the structure of the organization adjusts, information on the exact nature of the change becomes known only with some lag. The main conclusion obtained is that, as environment becomes more volatile, the optimal mode of the organization sharply switches from being totally flexible to being completely rigid, i.e. no intermediate configurations are essentially ever optimal. This has stark implications on the dichothomy of stability versus change that has been highlighted by recent organization literature.

BUILDING UP SOCIAL CAPITAL IN A CHANGING WORLD

This paper models the dynamic process through which a large society may succeed in building up its "social capital" by establishing a stable and dense pattern of interaction among its members. In the model, agents interact according to a collection of (idyosincratic) infinitely repeated Prisoner's Dilemma played on the existing social network. This network not only specifies the playing partners but, crucially, also determines how relevant strategic information diffuses or new cooperation opportunities are found. Over time, the underlying payoffs randomly change, i.e. display some "volatility". In response to it, agents react by creating new links and removing others. This combines into a complex but ergodic dynamic process, whose analysis is undertaken in different ways. First, we rely on its ergodicity to "compute" numerically its long-run regularities. Second, we use mean-field approximations to derive analytical results. Both routes are found in accord and also complementary. The long-run dynamics of the process sharply depends on environmental volatility, displaying the following features: (a) Only if volatility is not too high can the society sustain a dense social network and thus attain a large average payoff. (b) The social architecture endogenously responds to increased volatility by becoming more cohesive. (c) Network-based strategic effects are an essential buffer that preclude the abrupt collapse of the social network in the face of growing volatility. These conclusions are largely in tune with the points stressed in the social-capital literature.social capital, volatility.

LEARNING, NETWORK FORMATION AND COORDINATION

In many economic and social contexts, individual players choose their partners and also decide on a mode of behavior in interactions with these partners. This paper develops a simple model to examine the interaction between partner choice and individual behavior in games of coordination. An important ingredient of our approach is the way we model partner choice: we suppose that a player can establish ties with other players by investing in costly pair-wise links. We show that individual efforts to balance the costs and benefits of links sharply restrict the range of stable interaction architectures; equilibrium networks are either complete or have the star architecture. Moreover, the process of network formation has powerful effects on individual behavior: if costs of forming links are low then players coordinate on the risk-dominant action, while if costs of forming links are high then they coordinate on the efficient action.Networks, social learning, equilibrium selection

On the Evolution of Individualistic Preferences: Complete Versus Incomplete Information Scenarios.

We study the evolution of preferences via payoff monotonic dynamics in strategic environments with and without complete information. It is shown that, with complete information and subgroup matching, empirically plausible interdependent preference relations may entail the local instability of individualistic preferences (which target directly the maximization of material payoffs/fitness). The said instability may even be global if the subgroup size is large enough. In contrast, under incomplete information (unobservability of preference types), we show that independent preferences are globally stable in a large set of environments, and locally stable in essentially any standard environment, provided that the number of subgroups that form in thesociety is large. Since these results are obtained within the context of a very general model, they may be thought of as providing an evolutionary rationale for the prevalence of individualistic preferences.EVOLUTION; PREFERENCES; INCOMPLETE INFORMATION.

Network Formation and Social Coordination

This paper develops a simple model to examine the interaction between partner choice and individual behavior in games of coordination. An important ingredient of our approach is the way we model partner choice: we suppose that a player can establish ties with other players by unilaterally investing in costly pair-wise links. In this context, individual efforts to balance the costs and benefits of links are shown to lead to a unique equilibrium interaction architecture. The dynamics of network formation, however, has powerful effects on individual behavior: if costs of forming links are below a certain threshold then players coordinate on the risk-dominant action, while if costs are above this threshold then they coordinate on the efficient action. These findings are robust to a variety of modifications in the link formation process. For example, it may be posited that, in order for a link to materialize, the link proposal must be two-sided (i.e. put forward by both agents); or that, in case of a unilateral proposal, the link may be refused by the other party (if, say, the latter's net payoff is negative); or that a pair of agents can play the game even if connected only through indirect links.Networks, Links, Coordination games, Equilibrium selection, Risk dominance, Efficiency

Search and Homophily in Social Networks

We study the formation of social ties among heteogeneous agents in a model where meetings are governed by agents' directed search. The aim is to shed light on the important issue of homophily (the tendency of agents to connect with others of the same type). The essential contribution of the model is to provide a basic microfoundation for the opportunity/meeting biases that, as the literature highlights, are a crucial element of the phenomenon. Under the assumption that search is more effective in large pools, the equilibrium is characterized by a threshold in terms of group size: large groups only search among similar agents while smaller groups search in the whole population. This threshold behavior is consistent with the empirical evidence observed in a range of social environments such as high school friendships and interethnic marriages. And assuming that search is subject to small frictions, it also generates the bell-shaped form of the so-called Coleman index observed in the data. Other implications of the model supported by the evidence concern the pattern of cross-group ties among small groups, the linearity of excess homophily for large groups, and the positive effect on it of overall population size.Homophily, search, social networks, segregation.

La adopción por parte de parejas o personas homosexuales: un desafío en el reconocimiento de los derechos humanos

Trabajo final de graduación de 34 páginas en formato pdfEl proceso de la reivindicación de los derechos humanos de todas las personas pasa por etapas de reconocimiento, respeto, reflexión y asimilación de las diferencias y similitudes que tenemos como seres humanos, así como de cuales han sido eliminadas o negadas a pesar de su carácter inherente, universal e inalienable. Este proceso que de por si es complejo, empieza por eliminar estereotipos, patrones sociales aprendidos, concepciones sobre el “otro” y sobre lo que consideramos “normal” y “correcto” en una sociedad. En el caso de la homosexualidad, existe una serie de desafíos que vencer con respecto a los estereotipos y concepciones que sobre el tema se maneja, especialmente cuando desde hace varios años estos estereotipos se han convertido en parte de las herramientas para obstaculizar el reconocimiento de los derechos humanos de los gays, lesbianas, transexuales y bisexuales. Unido a lo anterior, la interiorización de la misma homosexualidad es un proceso muchas veces muy difícil para aquellas personas que deben enfrentarla venciendo prejuicios propios, de la sociedad y de lo que es socialmente aceptable. Para la sociedad igualmente no es un aspecto sencillo, pero es parte igualmente de un proceso que debe iniciar en aras de mejorar las condiciones de todas las personas en un Estado. Dentro de ese reconocimiento de derechos, la adopción de menores por parte de personas o parejas homosexuales, es un tema de discusión actual, entre sectores a favor y en contra, especialmente entre aquellos que lo consideran un derecho humano, así como que niegan esta posibilidad debido a una serie de factores que describiremos a continuación. El siguiente trabajo busca reflexionar sobre estos aspectos, especialmente para visualizar como esos patrones aprendidos y esas concepciones tienen efecto en el reconocimiento de los derechos humanos de las personas homosexuales, a través de las desmitificación y el análisis de dicha temática en el mundo actualUniversidad Estatal a Distancia de Costa Ric

Unfolding social hierarchies in large population games

Consider a large (continuum) population of finitely-lived agents organized in hierarchical levels.Every period, agents are matched to play a certain symmetric game. On the basis of the payoffsobtained, a certain p-fraction of those who performed best at each level are promoted upwords. Onthe other hand, newcomers replacing those who die every period enter at the lowest level andimitate unbiasedly (but subject to noise) the actions adopted at the highest one. In this context, the (unique) long-run behavior of the system is fully characterized for the wholeclass of 2x2 coordination games. The results crucially depend on the institutional parameter p(which refelcts how hierarchical - or selective - the society is) and on a purely ordinal criterion onthe payoffs of the game. In particular, efficent (or inefficent behaviour) may prevail in the long run -even when risk-dominated - if promotion in society is (or, respectively, is not) selective enough.Social hierarchies, large population games