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Teens tend go to bed later,get less sleep,and report more daytime sleepiness. Medical research emphasizes biological determinants of teens' disrupted sleep (i.e.,the timing of puberty and resultant drops in melatonin), rarely or inadequately considering youths' social ties as a determinant of sleep behaviors. Sociologists recognize how social ties affect health behaviors but have generally neglected sleep, especially among teens. Drawing on a sample of 974 teens from the Study of Early Child Care and Youth Development, this study controls for developmental and social relational factors to predict changes in youths' sleep patterns between 12 and 15 years of age. in general, social relational factors outperform developmental factors in determining youths' sleep patterns, particularly pointing to the importance of parental, peer, and school ties in promoting healthy sleep behaviors. The implications of these findings for further research are briefly discussed.

For a social media community to thrive and grow, it is critical that users of the site interact with each other and contribute content to the site. We study the role of social ties in motivating user preference expression, a form of user content contribution, in an online social media community. We examine the role of three types of ties, reciprocated , follower , and followee ties, and assess whether the structural and relational properties of a user’s social network moderate the social influence effect in user contribution. A unique disaggregate level panel data set of users’ contributions and social tie formation activities from an online music platform is employed to study the impact of social ties. To address identification issues, we adopt a quasi-experimental approach based on dynamic propensity score matching. The results provide strong evidence of the influence of online network ties in online contribution behavior. We find that the influence of reciprocated ties is the greatest, followed by influence from followee ties and then follower ties. Additional analysis reveals that reciprocated and followee ties have even greater influence when they contribute new information for a focal user. Structural embeddedness and tie strength among network ties are found to amplify the effect of social contagion in online contribution. We conduct several sensitivity and robustness checks that lend credible support to our findings. The results add to the greater understanding of social influence in online contribution and provide valuable managerial insights into designs of online communities to enable greater user participation. The online appendices are available at https://doi.org/10.1287/mnsc.2018.3087 . This paper was accepted by Anandhi Bharadwaj, information systems.

Recent years have seen a resurgence of interest in the relation between networks and spatial context. This review examines critically a selection of the literature on how physical space affects the formation of social ties. Different aspects of this question have been a feature in network analysis, neighborhood research, geography, organizational science, architecture and design, and urban planning. Focusing primarily on work at the meso- and microlevels of analysis, we pay special attention to studies examining spatial processes in neighborhood and organizational contexts. We argue that spatial context plays a role in the formation of social ties through at least three mechanisms, spatial propinquity, spatial composition, and spatial configuration; that fully capturing the role of spatial context will require multiple disciplinary perspectives and both qualitative and quantitative research; and that both methodological and conceptual questions central to the role of space in networks remain to be answered. We conclude by identifying major challenges in this work and proposing areas for future research.

Over the past 30 years investigators have called repeatedly for research on the mechanisms through which social relationships and social support improve physical and psychological well-being, both directly and as stress buffers. I describe seven possible mechanisms: social influence/social comparison, social control, role-based purpose and meaning (mattering), self-esteem, sense of control, belonging and companionship, and perceived support availability. Stress-buffering processes also involve these mechanisms. I argue that there are two broad types of support, emotional sustenance and active coping assistance, and two broad categories of supporters, significant others and experientially similar others, who specialize in supplying different types of support to distressed individuals. Emotionally sustaining behaviors and instrumental aid from significant others and empathy, active coping assistance, and role modeling from similar others should be most efficacious in alleviating the physical and emotional impacts of stressors.

This study presents results of a survey about social network website (SNW) usage that was administered to university students in China, Egypt, France, Israel, India, Korea, Macao, Sweden, Thailand, Turkey, and the United States. The offline and online social ties of SNW users were examined by nationality, levels of individualism-collectivism (I-C), gender, SNW usage, age, and access location. Contrary to existing literature, we found no differences in the number of offline friends between individualist and collectivist nations. Similarly, there was not a difference in the number of online social ties between individualist and collectivist nations. However, members of collectivist nations had significantly more online social ties never met in person. Heavy SNW users in individualist nations maintained significantly higher numbers of offline social ties; however, heavy SNW users in collectivist nations did not have higher numbers of offline social ties. Related implications and recommendations are provided.

We examine whether social ties between engagement auditors and audit committee members shape audit outcomes. Although these social ties can facilitate information transfer and help auditors alleviate management pressure to waive correction of detected misstatements, close interpersonal relations can undermine auditors' monitoring of the financial reporting process. We measure social ties by alma mater connections, professor-student bonding, and employment affiliation, and audit quality by the propensity to render modified audit opinions, financial reporting irregularities, and firm valuation. Our evidence implies that social ties between engagement auditors and audit committee members impair audit quality. In additional results consistent with expectations, we generally find that this relation is concentrated where social ties are more salient, or firm governance is relatively poor and agency conflicts are more severe. Implying reciprocity stemming from social networks, we also report some suggestive evidence that audit fees are higher in the presence of social ties between an engagement auditor and the audit committee. Collectively, our analysis lends support to the narrative that the negative implications—namely, worse audit quality and higher audit fees—of these social ties may outweigh the benefits.

We use 130 years of data on historical migrations to the U.S. to show a causal effect of the ancestry composition of U.S. counties on foreign direct investment (FDI) sent and received by local firms. To isolate the causal effect of ancestry on FDI, we build a simple reduced-form model of migrations: Migrations from a foreign country to a U.S. county at a given time depend on (1) a push factor, causing emigration from that foreign country to the entire U.S., and (2) a pull factor, causing immigration from all origins into that U.S. county. The interaction between time-series variation in origin-specific push factors and destination-specific pull factors generates quasi-random variation in the allocation of migrants across U.S. counties. We find that doubling the number of residents with ancestry from a given foreign country relative to the mean increases the probability that at least one local firm engages in FDI with that country by 4 percentage points. We present evidence that this effect is primarily driven by a reduction in information frictions, and not by better contract enforcement, taste similarities, or a convergence in factor endowments.

Because of the importance of human capital, a firm's choice of diversification targets will depend on whether these targets offer opportunities for leveraging existing human resources. We propose to quantify the similarity of different industries' human capital or skill requirements, that is, the industries' skill relatedness, by using information on cross-industry labor flows. Labor flows among industries can be used to identify skill relatedness, because individuals changing jobs will likely remain in industries that value the skills associated with their previous work. Estimates show that firms are far more likely to diversify into industries that have ties to the firms' core activities in terms of our skill-relatedness measure than into industries without such ties or into industries that are linked by value chain linkages or by classification-based relatedness.

Despite increasing attention to the role of social ties in emerging economies, few studies have explicitly distinguished the differential roles of business versus political ties. Drawing on relational governance and institutional theories, this study offers a contingent view of business and political ties in China. The findings from a survey of 241 Chinese firms indicate that business ties have a stronger positive effect on performance than political ties, and both effects depend on institutional and market environments. Business ties are more beneficial when legal enforcement is inefficient and technology is changing rapidly, whereas political ties lead to greater performance when general government support is weak and technological turbulence is low. These findings indicate that firms operating in China should be cautious in their use of business and political ties and adapt their tie utilization to changing institutional and market environments.