One-shot exchange networks and the shadow of the future

From the Prisoner's Dilemma and other games, it is well known that strategy selection in one-shot games can be very different from that in iterated games. Because exchange structures were studied only as iterated games, whether one-shot structures differ was not known. Nor have exchange theories previously considered whether events in structures would be different if studied as one-shot games. This paper offers new theory to predict one-shot exchange structures and one-shot experiments to test that theory. As predicted, the experiments found that processes and outcomes of one-shot exchange structures are quite different from those of iterated exchange structures. For example, certain relations that are strategically used as threats in iterated exchange structures occur very rarely in one-shot structures. It follows that power differences in one-shot structures regress from those observed for repeated structures.     

Dynamic exchange networks

Considering the theoretical and empirical untenability of static exchange networks, researchers have asked how exchange outcomes change when links are added or deleted. The present paper assesses the validity of seemingly sensible propositions concerning the effects of adding and deleting a link on (i) the payoffs of the actors in the link, (ii) the payoffs of actors in neighboring links and (iii) the variance of payoffs in the exchange network. The propositions were examined by applying expected value theory (EVT) to all 13,597 networks up to size 8. All propositions were falsified. Some falsifications of propositions could be attributed to EVTs prediction that actors use sub-optimal exchange relations. Since other well-known theories of exchange, like power-dependence theory and network exchange theory, also predict that actors use sub-optimal relations, these results are robust to selection of the theory of exchange.     

The stability of exchange networks

Economic and sociological exchange theories predict divisions of exchange benefits given an assumed fixed network of exchange relations. Since network structure has been found to have a large impact on actors’ payoffs, actors have strong incentives for network change. We answer the question what happens to both the network structure and actor payoffs when myopic actors change their links in order to maximize their payoffs. We investigate the networks that are stable, the networks that are efficient or egalitarian with varying tie costs, and the occurrence of social dilemmas. Only few networks are stable over a wide range of tie costs, and all of them can be divided into two types: efficient networks consisting of only dyads and at most one isolate, and Pareto efficient and egalitarian cycles with an odd number of actors. Social dilemmas are observed in even-sized networks at low tie costs.     

Theories of network exchange: Anomalies,desirable properties,and critical networks

The present study evaluates four well-known theories of exchange in networks. In previous research these theories’ predictions were compared for a small set of networks using experimental data. We compared their predictions for all 12,112 networks up to size 8. By comparing these predictions we (i) identified anomalies in theories of network exchange, (ii) investigated to what extent the theories satisfy basic principles of exchange, (iii) identified ‘critical’ networks for which predictions are very different. We conclude that exchange in networks is not yet well understood.     

Resource characteristics in social exchange networks: Implications for positional advantage

Despite the wide range of resources that traverse social networks, social exchange research has focused on only a narrow subset. Notably, prior social exchange research has not considered resources like information that have the capacity to diffuse through networks. The current study investigates how differences between the standard social exchange resource and an information-type resource affect the advantage provided by one's network position. Results of a laboratory experiment support predictions and offer two new insights to the foundations of positional advantage: (1) the location of advantageous positions in a network differs by resource characteristics, and (2) only in particular situations is a single position able to experience high levels of both power and exchange frequency.     

Spine segments in small world networks

Investigations of small world contact networks, defined as networks with a short characteristic path length and a substantial local clustering of contacts in the neighborhood of each node, have emphasized the process performance of such networks. The argument that large-scale, small world, contact networks are structures with startlingly efficient process performance is premised on the existence of shortcuts, without which the characteristic path lengths of the networks would be substantially larger. No doubt, given a high probability of transmission in each contact of a network, such shortcuts are a potential structural basis of reliable flows of information, influence, material and disease. However, interpersonal contacts are often markedly unreliable transmission conduits, and the average shortcut contact may be a more unreliable, episodic, transmission conduit than the average contact of cliques. With markedly unreliable contacts, fundamental helix substructures, that are parallel-transmission subsystems of the contact network, importantly enter into the analysis of network performance. These substructures of disjoint path redundancies are based on the local clustering of contacts in the neighborhoods of each node. Drawing on network reliability theory, this article presents an approach in which intersecting cliques of contact networks are a theoretically important construct in the specification of the transmission implications of observed contact networks. Clique intersections are a structural basis of path redundancies that enable reliable transmission among the nodes of contact networks consisting of contacts that may or may not be active conduits of transmissions during some period of time. The strong contacts that occur among clique members further enhance the contributions of these path redundancies.     

A comparison of email networks and off-line social networks: A study of a medium-sized bank

Recently there has been a surge in the availability of online data concerning the connections between people, and these online data are now widely used to map the social structure of communities. There has been little research, however, on how these new types of relational data correspond to classical measures of social networks. To fill this gap, we contrast the structure of an email network with the underlying friendship, communication, and advice seeking networks. Our study is an explorative case study of a bank, and our data contains emails among employees and a survey of the ego networks of the employees. Through calculating correlations with QAP standard errors and estimating exponential random graph (ERG) models, we find that although the email network is related to the survey-based social networks, email networks are also significantly different: while off-line social networks are strongly shaped by gender, tenure, and hierarchical boundaries, the role of these boundaries are much weaker in the email network.     

Familial groups in social networks

Many structural definitions for social community have been proposed in attempt to characterize and further understand the structure of social relationships. Algorithms using quantitative concepts such as centrality measures, spectral methods and other clustering measures have been used to compute social communities. While these methods have had much success in extracting meaningful subgroups in social and biological (and other) networks, they do not necessarily reveal the defining structure of social attraction.     

Transitional appreciation of equilibrium exchange rates and the ERM II

A suitable parity for exchange rate fixing can be derived from an analysis of the equilibrium exchange rate. As the equilibrium exchange rates of the new EU 5 countries, the Czech Republic, Hungary, Poland, Slovenia, and the Slovak Republic, tend to exhibit appreciation trends, credibility of the potential commitment to fixed exchange rate parity with respect to the euro can be undermined. In order to investigate this issue, we estimate a behavioral model of real exchange rates for EU 5 countries and derive the respective equilibrium real exchange rates. Using the linear-quadratic filter we estimate permanent equilibrium exchange rates and their stationary points. We find that as of 2004 fixing of the national currencies to the euro should not be undermined by further significant trend appreciation in the equilibrium exchange rates of the EU 5 countries, in aggregate.     

Value provided by interfamily economic exchange of goods and services in two cultures

The value of goods and services provided through interfamily economic exchange is examined from a household survey. The existence of an exchange system in society was documented. Over half of the respondents reported that economic transfers between families were important to the quality of their life. Estimated values varied with personal health conditions, importance attached to providing goods and services, years of residence in the community, primary recipient of services, ethnic culture, sex of respondent, and type of service provided. Estimated values can be used for calculating economic loss in community disruption and relocation, measuring family full income, and estimating the importance of nonmarket economic activity in society.The study contributes to interregional Agricultural Experiment Station Research Project NC-128 Quality of Life as Affected by Area of Residence. Cooperating States: Arizona, California, Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, Nevada, and Texas.Dr. Williams is an Associate Professor in the Department of Consumer Sciences and Retailing, Purdue University, West Lafayette, Indiana 47907. Her Ph.D. was received from Purdue in Family Economics and Management. Current research areas are income adequacy, economic security, financial problems, and financial counseling.     

The regionalization of intergovernmental organization networks: A non-linear process

We use a computationally intensive approach to explore how the world polity is becoming more fractured along regional lines. We discover that regionalization is a non-linear process and show that the world polity oscillates between fracturing and re-contracting. We do so by applying the technique of Hierarchical Link Clustering (HLC) to yearly intergovernmental organization (IGO) networks from 1971 to 2005. The mechanism for explaining this seemingly contradictory result lies in the behavior of IGOs, which depends largely on the organizations’ geographic focus: regionally focused IGOs create more communities, thereby fracturing the world polity, while globally focused IGOs create relationships across communities, thereby bringing communities together. Every year, different percentages of global and regional IGOs enter the network, thereby producing oscillations in the overall structure.     

Community e-gateways: locating networks and learning for social inclusion

The provision of community e-gateways (community-based facilities providing public access to computers and the Internet) has been seen as a way to address the 'digital divide', particularly for people from deprived neighbourhoods. In the UK, policy and practitioner literature has stressed that for these centres to be successful they need to have strong social connections and be able to provide opportunities for interactive learning and content creation. Through a detailed analysis of one community e-gateway, which formed part of a wider study of public access provision, this article analyses the strengths and weaknesses of this advice drawing on broader sociological literature relating to social networks, network mapping and communities of practice. It concludes that greater attention needs to be paid to the significance of weak ties, two-way boundary spanning and the resource requirements of social networks for the policy objectives to be fully achieved.     

A Nash bargaining model for simple exchange networks

Starting from exogenously given negotiation networks, sociological exchange theories explain bilateral divisions of fixed surpluses (e.g., cake, dollar) as consequences of the partners’ structural embeddedness. In accordance with the available experimental evidence, we focus on simple exchange networks and present a formal model for predicting profit splits from such structures. In contrast to other approaches, we combine the generalized Nash bargaining solution from game theory with the assumption that both relational features and network positions affect exchange outcomes. The resulting point predictions for profit splits correspond closely with experimental results obtained by Cook et al. [Cook, K.S., Emerson, R.M., Gillmore, M.R., Yamagishi, T., 1983. The distribution of power in exchange networks: theory and experimental results. American Journal of Sociology 89, 275–305], Lovaglia et al. [Lovaglia, M.J., Skvoretz, J., Willer, D., Markovsky, B., 1995. Negotiated exchanges in social networks. Social Forces 74, 123–155], Markovsky et al. [Markovsky, B., Willer, D., Patton, T., 1988. Power relations in exchange networks. American Sociological Review 53, 220–236], Simpson and Willer [Simpson, B., Willer, D., 1999. A new method for finding power structures. In: Willer, D. (Ed.), Network Exchange Theory. Praeger, Westport, CT, pp. 270–284], Skvoretz and Fararo [Skvoretz, J., Fararo, T.J., 1992. Power and network exchange: an essay toward theoretical unification. Social Networks 14, 325–344], Skvoretz and Willer [Skvoretz, J., Willer, D., 1993. Exclusion and power: a test of four theories of power in exchange networks. American Sociological Review 58, 801–818] as well as Yamagishi et al. [Yamagishi, T., Gillmore, M.R., Cook, K.S., 1988. Network connections and the distribution of power in exchange networks. American Journal of Sociology 93, 833–851].     

Power in politically charged networks

We offer a theory and measure for determining powerful nodal positions based on potential inter-actor control in “politically charged” networks, which contain both allies and adversaries. Power is derived from actors that are dependent on the focal actor and sociometrically weak, either due to a lack of alternative allies or from being threatened by others. We create a new Political Independence Index (PII), compare it to other established measures, and illustrate its use in the setting of an international network of alliances and military conflicts from 1946 to 2000. Results show that politically independent nations as measured by PII have smaller increases in military personnel than others over time.     

Assessing harmfulness and vulnerability in global bipartite networks of terrorist-target relationships

In this paper we leverage a massive attack-focused terrorist database and we design a dynamic bipartite network analysis to examine the structural evolution of terrorists-targets relationships. We introduce two novel measures to jointly assess harmfulness and vulnerability of terrorist and target groups, both at local and global level. Statistical validation using null models provides evidence that the information contained in these measures is new and not included in other variables, thus emphasizing the usefulness of these topological indicators. Finally, a policy-support experiment designed as network dismantling-like drill is proposed to assess the effects of potential attack preventive strategies.     

The impact of negotiated exchange on trust and trustworthiness

Negotiated exchanges and trust problems can be regarded as two different forms of exchange, the former representing exchanges with negotiation and binding contracts, the latter representing asymmetric transactions in which one actor has the opportunity to deceive the other. Both forms of exchange have been extensively studied, but the two respective research traditions exhibit very little overlap. In this paper, we investigate the effects of negotiated exchanges in different network structures on the development of mutual trust. We derive hypotheses from various theories and test them by means of an experiment in which subjects first undertake a series of negotiated exchanges under different power conditions, and then face a trust problem with one of the actors that have been involved in the previous exchanges. The trust problem is operationalized by means of the Investment Game which allows us to look separately at trust and trustworthiness. Our results demonstrate that negotiated exchanges increase mutual trust, but not trustworthiness.     

Continental transnational activism and women workers' networks within NAFTA

In this article, I present some experiences of transnational networking among women workers, women's groups, and feminist organizations at both the transcontinental and transborder level in the FTAA and NAFTA areas. These transnational efforts are analyzed as forms of resistance to the encroachments of global capital. The record of these networks is both encouraging and problematic. Encouraging because certain issues have received greater attention from both the state and multinational companies, and Mexican organizations have received strategic support to empower themselves and even, in some cases, develop a feminist workers' perspective. The record is also problematic as cooperation is not always free from conflict, or asymmetric relations, among the organizations. Asymmetries often reflect unequal access to power and financial resources. In spite of this, it seems undeniable that transnational networks among women's organizations are modeling new forms of resistance to the processes of global restructuring.     

Assessing the bias in samples of large online networks

We consider the sampling bias introduced in the study of online networks when collecting data through publicly available APIs (application programming interfaces). We assess differences between three samples of Twitter activity; the empirical context is given by political protests taking place in May 2012. We track online communication around these protests for the period of one month, and reconstruct the network of mentions and re-tweets according to the search and the streaming APIs, and to different filtering parameters. We find that smaller samples do not offer an accurate picture of peripheral activity; we also find that the bias is greater for the network of mentions, partly because of the higher influence of snowballing in identifying relevant nodes. We discuss the implications of this bias for the study of diffusion dynamics and political communication through social media, and advocate the need for more uniform sampling procedures to study online communication.