Neuroimaging Studies Reveal the Subtle Difference Among Social Network Size Measurements and Shed Light on New Directions

Abstract

Social network size is a key feature when we explore the constructions of human social networks. Despite the disparate understanding of individuals’ social networks, researchers have reached a consensus that human’s social networks are hierarchically organized with different layers, which represent emotional bonds and interaction frequency. Social brain hypothesis emphasizes the significance of complex and demanding social interaction environments and assumes that the cognitive constraints may have an impact on the social network size. This paper reviews neuroimaging studies on social networks that explored the connection between individuals’ social network size and neural mechanisms and finds that Social Network Index (SNI) and Social Network Questionnaires (SNQs) are the mostly-adopted measurements of one’s social network size. The two assessments have subtle difference in essence as they measure the different sublayers of one’s social network. The former measures the relatively outer sub-layer of one’s stable social relationship, similar to the sympathy group, while the latter assesses the innermost layer—the core of one’s social network, often referred to as support clique. This subtle difference is also corroborated by neuroimaging studies, as SNI-measured social network size is largely correlated with the amygdala, while SNQ-assessed social network size is closely related to both the amygdala and the orbitofrontal cortex. The two brain regions respond to disparate degrees of social closeness, respectively. Finally, it proposes a careful choice among the measurements for specific purposes and some new approaches to assess individuals’ social network size.

Behavioral and neural correlates of social network size: The unique and common contributions of face recognition and extraversion

“…Given the stable individual differences in SNS, the neural bases of SNS and its behavioral relevance (e.g., personality and social cognition) may be manifested in the structural and functional variables, which could be detected by structural magnetic resonance imaging (MRI) and resting state functional MRI (rs-fMRI; DeYoung, 2010; Mar et al, 2013). Consistent with the social brain hypothesis (Dunbar, 2012;Liu et al, 2018;Mars et al, 2012), structural MRI studies have found correlation between the self-reported SNS and grey matter volume/density of the brain regions subserving social behaviors, including the amygdala (Bickart et al, 2011;Liu et al, 2018;Von Der Heide et al, 2014), ventromedial prefrontal cortex (vmPFC; Lewis et al, 2011;Noonan et al, 2018), superior temporal sulcus (STS; Kanai, Bahrami, Roylance, et al, 2012), precuneus (Noonan et al, 2018), and orbitofrontal cortex (Lewis et al, 2011;Von Der Heide et al, 2014).…”

“…Better social abilities and larger network size may help humans to cooperate with each other (Tomasello, 2001). Research on human's social networks has expanded greatly in the sociological and psychological fields, and it has been shown that different factors may result in individual differences of social network size (SNS; Liu et al, 2018;Totterdell et al, 2008). In many cases, the SNS has been found to be related to particular traits of people's personality (Fang et al, 2015;Roberts et al, 2008;Selden & Goodie, 2018).…”

Individual differences in social reward and threat expectancies linked to grey matter volumes in key regions of the social brain

“…63 Our results may reflect a neural embedding of such self-related affective valuation, perhaps accounting for the link between vmPFC macrostructure and adaptive social functioning and well-being. 181,182 Funding This work was funded by an ESRC PhD studentship and Wellcome Trust Institutional Strategic Support Fund…”

The cross‐sectional association of cognitive stimulation factors and cognitive function among Latino adults in Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

“…To our knowledge, there are no family‐based interventions that focus on cognitive health, but there are family‐based interventions that focus on health outcomes [37]. There is evidence on the benefits of stronger social networks and cognitive function using neuropsychological tests [38] and neuroimaging data [39]. Although educational attainment is considered to be static, there is an opportunity for adult educational programming and continued support for health educational opportunities.…”