David R. Schaefer

Misery Does Not Love Company Network Selection Mechanisms and Depression Homophily

Conventional wisdom holds that friends protect against depression through the social support they provide; however, depression likely has a role in structuring friendship networks. In particular, we investigate friend selection mechanisms responsible for similarity in depression among friends (i.e., homophily). Preference is one explanation, yet several correlates of depression make homophilous selection among depressed individuals unlikely. We propose two alternative mechanisms—avoidance and withdrawal—that can produce depression homophily in the absence of preference. These alternative mechanisms create homophily indirectly by limiting friendship partners available to depressed individuals. We test the preference, avoidance, and withdrawal mechanisms using data from the National Longitudinal Study of Adolescent Health and a dynamic network model. Results provide support for the withdrawal mechanism. These findings help explain how depression affects friend selection and have broader implications for understanding selection mechanisms responsible for network patterns such as homophily.

Fragile and Resilient Trust: Risk and Uncertainty in Negotiated and Reciprocal Exchange*

Both experimental and ethnographic studies show that reciprocal exchanges (in which actors unilaterally provide benefits to each other without formal agreements) produce stronger trust than negotiated exchanges secured by binding agreements. We develop the theoretical role of risk and uncertainty as causal mechanisms that potentially explain these results, and then test their effects in two laboratory experiments that vary risk and uncertainty within negotiated and reciprocal forms of exchange. We increase risk in negotiated exchanges by making agreements nonbinding and decrease uncertainty in reciprocal exchanges by having actors communicate their intentions. Our findings support three main theoretical conclusions. (1) Increasing risk in negotiated exchange produces levels of trust comparable to those in reciprocal exchange only if the partners trustworthiness is near-absolute. (2) Decreasing uncertainty in reciprocal exchange either increases or decreases trust, depending on network structure. (3) Even when reciprocal and negotiated exchanges produce comparable levels of trust, their trust differs in kind, with reciprocal exchange partners developing trust that is more resilient and affect-based.

An assessment of the impact of quality-of-life policing on crime and disorder

In this paper we examine the impact of quality-of-life policing on crime and disorder. Specifically, we examine a quality-of-life initiative conducted by the Chandler, Arizona Police Department, which was grounded in an operational strategy of policing social and physical disorder. Using data on calls for service, we employ an interrupted time-series analysis to examine the effect of the intervention on 10 offense categories within the overall target area and within four zones that constitute the target area. The findings suggest that the quality-of-life initiative exerted the strongest effect on two categories of crime and disorder: public morals and physical disorder. Diffusion of benefit and displacement effects were also observed in nearby areas. We discuss the implications of the findings for policy makers and researchers.

Fundamental Principles of Network Formation among Preschool Children.

The goal of this research was to investigate the origins of social networks by examining the formation of childrens peer relationships in 11 preschool classes throughout the school year. We investigated whether several fundamental processes of relationship formation were evident at this age, including reciprocity, popularity, and triadic closure effects. We expected these mechanisms to change in importance over time as the network crystallizes, allowing more complex structures to evolve from simpler ones in a process we refer to as structural cascading. We analyzed intensive longitudinal observational data of childrens interactions using the SIENA actor-based model. We found evidence that reciprocity, popularity, and triadic closure all shaped the formation of preschool childrens networks. The influence of reciprocity remained consistent, whereas popularity and triadic closure became increasingly important over the course of the school year. Interactions between age and endogenous network effects were nonsignificant, suggesting that these network formation processes were not moderated by age in this sample of young children. We discuss the implications of our longitudinal network approach and findings for the study of early network developmental processes.

Health and the Structure of Adolescent Social Networks.

Much research has explored the role of social networks in promoting health through the provision of social support. However, little work has examined how social networks themselves may be structured by health. This article investigates the link between individuals’ health and the characteristics of their social network positions. We first develop theoretical predictions for how health may influence the structure of adolescent networks. We then test these predictions using longitudinal analysis of the National Longitudinal Study of Adolescent Health (Add Health). We find important relationships between the health status of adolescents and the characteristics of the social network positions within which they are embedded. Overall we find that adolescents in poor health form smaller local networks and occupy less central global positions than their healthy peers. These results also have implications for social network research, expanding the scope of factors responsible for the network positions individuals occupy.

The role of sex of peers and gender-typed activities in young children's peer affiliative networks: a longitudinal analysis of selection and influence.

A stochastic actor-based model was used to investigate the origins of sex segregation by examining how similarity in sex of peers and time spent in gender-typed activities affected affiliation network selection and how peers influenced childrens (N = 292; Mage = 4.3 years) activity involvement. Gender had powerful effects on interactions through direct and indirect pathways. Children selected playmates of the same sex and with similar levels of gender-typed activities. Selection based on gender-typed activities partially mediated selection based on sex of peers. Children influenced one anothers engagement in gender-typed activities. When mechanisms producing sex segregation were compared, the largest contributor was selection based on sex of peers; less was due to activity-based selection and peer influence. Implications for sex segregation and gender development are discussed.

Youth co-offending networks: An investigation of social and spatial effects

Abstract This research tests the relative contribution of social distance and spatial distance to the presence of ties between neighborhoods based on youth co-offending. Using official court data from a large U.S. metropolitan area, a set of dyad independence and exponential random graph models are estimated in order to investigate the characteristics of neighborhoods that foster co-offending. Results reveal significant effects of both social and spatial distance. Social distance contributes to network structure net of spatial proximity, though spatial factors better explain the overall network structure. These results have methodological implications for the analysis of spatial effects and criminal behavior.

The Validity of Police Gang Intelligence Lists: Examining Differences in Delinquency Between Documented Gang Members and Nondocumented Delinquent Youth

Over the past 15 years, the United States has seen a dramatic increase in the number of specialized gang units established by police departments across the country. The majority of these units were established for the purpose of gathering intelligence on gangs, gang members, and gang-related activity. The present study seeks to advance the understanding of the usefulness of gang intelligence systems. In particular, the authors focus on how successful the police are at identifying and documenting youth whom they believe pose a substantial threat to the community. Using data obtained from the Mesa, Arizona, police departments gang unit and the Maricopa County Juvenile Probation Department, the authors found that gang lists may be more helpful to the police than first believed. Policy implications are presented along with recommendations for future research.

Using Social Network Analysis to Clarify the Role of Obesity in Selection of Adolescent Friends

OBJECTIVES We used social network analysis to examine how weight status affects friend selection, with an emphasis on homophily and the social marginalization of overweight youths. METHODS We used an exponential random graph model to assess the effects of body mass index (BMI) on friend selection while controlling for several alternative selection processes. Data were derived from 58,987 students in 88 US middle and high schools who took part in the 1994 to 1996 National Longitudinal Study of Adolescent Health. RESULTS On average, overweight youths were less likely than nonoverweight youths to be selected as a friend; however, this effect differed according to the BMI of the person initiating the friendship. Nonoverweight youths were 30% more likely to select a nonoverweight friend than an overweight friend, whereas overweight youths were largely indifferent to the weight status of their friends. Friendship ties from overweight youths to nonoverweight peers were more likely than ties in the reverse direction. CONCLUSIONS We found evidence consistent with homophily and social marginalization but only for the selection behavior of nonoverweight youths. We conclude that avoidance of overweight friends is the primary determinant of friendship patterns related to BMI.

With a Little Help from My Friends? Asymmetrical Social Influence on Adolescent Smoking Initiation and Cessation

This study investigates whether peer influence on smoking among adolescents is asymmetrical. We hypothesize that several features of smoking lead peers to have a stronger effect on smoking initiation than cessation. Using data from the National Longitudinal Study of Adolescent Health we estimate a dynamic network model that includes separate effects for increases versus decreases in smoking, while also controlling for endogenous network change. We find that the impact of peer influence is stronger for the initiation of smoking than smoking cessation. Adolescents rarely initiate smoking without peer influence but will cease smoking while their friends continue smoking. We discuss the implications of these results for theories of peer influence and health policy.