SOCIAL NETWORK TIES: HOW SIZE AND DIVERSITY IMPACT OUR WELLBEING

We all play multiple roles in life. Some days it may even feel like an identity juggling contest. You are a mother and a daughter, a colleague, a mentor, a sister, a friend, a neighbor, a congregation member, a coach, a wife or significant other. Most US adults have social ties with many people, including friends, family, co-workers, and other acquaintances. It is nearly impossible for most people to reliably list all the people they know, but using a mathematical model, social analysts estimate that, on average, a US adult has approximately 634 social ties with people, including social media, and for heavy social media users, that number is higher. 

Humans are driven by a fundamental need for social connection, that is, perceiving that one belongs in a social network and can rely on others for support. At any given time, most of us manage several relational ties or roles within our social network. The quantity and quality of our relational ties and the perception of accessible social support within our social networks are robustly associated with better mental and physical health across the lifespan.

SOCIAL NETWORKS

A social network is a pattern of interpersonal relationships, generally defined by who knows who or who communicates with whom, through which resources and benefits are shared and obtained. Participation in social networks is considered by many to be fundamental to human survival and therefore an essential component of psychological well-being. In this respect, personal networks are particularly valuable. But quality is not the only social network element that influences wellbeing. The structural elements (the size, density, and diversity) of our social networks are critically associated with physical and mental well-being. Here we look at the social network characteristic of relational diversity.

Not to be confused with ethnic and social diversity, relational diversity refers to the number of types of social ties an individual has within his network. This reflects the many types of different people one interacts with such as family, friends, co-workers, acquaintances, and strangers. It is a measure of the varied relationships and roles that the people in a social network play or fulfill. Indeed, the link between social connection and well-being is well-documented. The amount of social interaction in an individual’s daily life is one of the most consistent predictors of psychological well-being.

THE SOCIAL BRAIN & THE SOCIAL BRAIN HYPOTHESIS

In 1990, neuroscientist Lesley Brothers proposed that there are specific brain regions dedicated to social cognition, which she called the social brain. She identified the amygdala, orbital frontal cortex, and temporal cortex as the main components of the social brain. Current social neuroscience conceives of the social brain as comprised of two network systems: the amygdala network and the mentalizing network. A network system in the brain is a collection of brain regions that are connected and interact with each other to perform a specific function. In the case of the social brain, these complex networks work together to enable us to interact with others, to understand and respond to others. Today, such regions within these networks are thought to include the amygdala, the orbital frontal cortex, the medial prefrontal cortex, the para-cingulate cortices, the temporal lobes, and the posterior superior temporal sulcus. Key functions of the social brain are social cognition, empathy and theory of mind, and social decision making.

In the latter half of the 1990s, the social brain hypothesis was built upon the concept of the social brain. This hypothesis, as presented by Barton and Dunbar (1997), explains the link between the large brains of anthropoid primates and their intense sociality. Research has shown a correlation between the size of the neocortex (involved in higher order functions) and the size of social groups in primates. The hypothesis suggests that the cognitive demands of living in large, complex social groups, such as the ability to sustain many individual relationships, drove the evolution of large brains and superior socio-cognitive skills. Primates, including humans, live in intricate social systems that involve forming alliances, understanding social hierarchies, and managing relationships. Such social systems necessitate a larger brain to process and manage these interactions.

The hypothesis offered by Dunbar and since echoed by other researchers, suggest that social cognition is linked to specialized brain systems that help humans and other primates evaluate the intentions and dispositions of others, to form attachments and establish a social identity, and to execute within and between group behaviors of cooperation and competition.

The oft quoted “Dunbar’s number” of 150 is a number derived from the correlation between primate brain size and average social group size. Dunbar extrapolated this relationship to humans, using the average human brain size to predict a social group size of approximately 150. Inherent in Dunbar’s number is a theoretical cognitive limit to the number of stable social relationships one can maintain and suggests that humans can comfortably maintain about 150 stable relationships. His theory of concentric circles of relationships, with larger circles correlating with a larger number of individuals but with a decrease in level of closeness or intimacy is based on the idea that each social layer has three times as many relationships as the previous layer. Dunbar’s numbers are supported by evidence across cultures, even with the rise of social media. While other research has sometimes suggested numbers lower and others upwards of 160, the 150 is an approximation from which researchers have not deviated far.

THE IMPORTANCE OF SOCIAL TIE DIVERSITY

In the biological sciences there are few topics as important as the consequences of diversity for the functioning and transformation of ecosystems. Ecosystems with greater biodiversity are more resilient, healthy, and live longer than their less diverse counterparts. As humans, our social networks are not unlike ecosystems when defined simply as the network of living organisms that live or work or otherwise interact together creating communities and connections between people. Just like natural ecosystems, social networks are complex, dynamic, and interconnected systems. Our networks exhibit the symbiotic relationships and the food chain of ecosystems: our social world is flush with collaborations, partnerships, and mutual support between users; and just as energy flows from one organism to another in a food chain, information and influence flow from one user to another in a social network. So, when our networks are undersized with fewer varied connections, our ability to physically and emotionally thrive is just as much at risk as any other ecosystem.

"As humans, our social networks are not unlike ecosystems when defined simply as the network of living organisms that live or work or otherwise interact together creating communities and connections between people."

PHYSICAL AND MENTAL WELLBEING:

The importance of social relationships for health and well-being has been extensively demonstrated. The relationship between social connectedness and health outcomes rivals that of well-established health risk factors such as smoking and obesity. Researchers have found the most consistent and provocative results in groups of studies focusing on social integration. Social integration is defined as one's membership in a diverse social network. Prospective community studies indicate that those with more types of relationships live longer. More types of relationships include a variety of connections such as being married, having close family members, friends, and neighbors. Furthermore, membership within groups --a type of relational or social tie, defined as belonging to social, political, and religious groups --is associated with reduced mortality and higher reports of satisfaction and happiness. 

Social connectedness is especially of importance to vulnerable groups such as the elderly and the disabled. Perceived social support from a variety of relationships seems to offer a sense of security and reliance for those with physically disabilities. While true for middle aged adults, even more so with the elderly we see that more diverse social networks are associated with a lower risk of mortality and higher physical functioning. It may be that the diversity of social networks in the elderly are even important to their wellbeing than the quality of their relationships, a finding that some researchers interpret as diverse social roles offer meaning or purpose in life, which is then linked to better quality of life measures.

Diverse social network ties are a known protector of mental health. The amount of social interaction in one’s life may be the most consistent predictor of psychological wellbeing. Research suggests that being connected to more types of people can make one more resilient to depression and anxiety. This is especially true for young adults who may have experienced disruptions to their social lives. Studies have shown that social connectedness is associated with decreased anxiety, loneliness, suicidal ideation, and depression. Increased social connection during the pandemic was also shown to improve mental health indicators.

But more than a shield against psychiatric disorders, the characteristics of social networks such as size and diversity may be a factor in how happy people report themselves to be. Evidence demonstrates that happier people spend more time with close others. But it is not just our close circle of social ties that impact our sense of wellbeing and happiness. Colleagues at Harvard Business School evaluated 4 different surveys from around the world and reported that people with more diverse social contacts, regardless of degree of intimacy, reported greater happiness than those with fewer contacts or restricted networks.  Moreover, recent work suggests that individuals have important conversations with their “weak” social ties (distant others); and laboratory experiments demonstrate that everyday social interactions with strangers can elicit as much happiness or satisfaction as interacting with one’s significant other.

COGNITIVE FUNCTIONING & ALZHEIMER’S DISEASE:

Healthy social connections are increasingly linked to brain health. Engaging in social interactions can help keep our brains flexible and boost brain resilience. Perhaps the most striking positive correlation is that of diverse social ties and reduced risk of developing Alzheimer’s disease and other forms of dementia. Studies indicate that maintaining strong social connections and staying mentally active as we age may lower the risk of cognitive decline and dementia. 

Studies suggest that social network characteristics impart these benefits through increased gray matter density. Gray matter is essential for many human functions, including controlling movement, regulating emotions, and retaining memories. Gray matter density in specific brain regions linked to social cognition, empathy, and emotional processing is greater in individuals with larger and more diverse social networks than individuals with more restricted social networks. Studies have shown a correlation between the density of gray matter in the amygdala--a brain region vital to emotional and social processing, attention to social cues, and memory formation--and the size of both online and offline social networks. The orbitofrontal cortex (OFC), a key player in social decision making, evaluating rewards and punishments, and understanding social cues, is associated with social wellbeing. Research demonstrates greater OFC gray matter density among highly socially engaged seniors than their counterparts. 

The brain’s neural plasticity is thought to be one of the mechanisms responsible for increased gray matter density: engaging with diverse social circles stimulates the brain to form new connections and adapt, leading to increased gray matter density in relevant regions. Also suggested is that greater and more diverse social networks likely offer more social support options: strong social bonds can reduce stress, which has a positive impact on brain health, including gray matter density.

THE PRACTICAL IMPLICATIONS FOR ALL:

There is a Chinese proverb that says, "More friends, more ways," meaning the more friends you have, the more solutions you will find to your difficulties. The idea that the larger and more diverse your network, the more connections you have that can transmit information, provide support, and encourage a variety of activities and memberships is perhaps intuitive. That it can protect your health and extend your longevity as much as any other healthy behavior, revolutionizes the way we conceive of healthcare indicators and outcomes.

According to the World Health Organization (WHO), since the outbreak of the COVID-19 pandemic, anxiety and depression prevalence increased by 25% globally. And despite their drop in 2022, they remain higher than pre-pandemic levels. For individuals aged 35 to 44, there has been a significant increase in mental health diagnoses reported in 2023 compared with 2019 (45% vs. 31%). The CDC reports that chronic diseases are a significant public health threat, and their burden is expected to continue to grow in the coming years. In 2023, an estimated 6.7 million Americans were living with a chronic disease, and that number is projected to nearly triple to 14 million by 2060. Also threatening the wellbeing of the population is the alarming rate at which Alzheimer’s disease is increasing due to the growing number of citizens aged 65. Research increasingly points to social isolation as a significant risk factor for Alzheimer's disease and social engagement as protective. Understanding the neural mechanisms underlying social connection and its effects can inform prevention strategies and may identify early markers of many diseases, allowing for earlier interventions.

Measures of our social networks and our social connectedness are more important today than ever. Much like Dunbar’s concentric circles of relationships that grow in number as distance increases, the Self-Centric Relational System (SCRS) is a screenshot of the number, type, and degree of closeness of an individual’s or client’s social network at any given time. It affords those in the helping field an opportunity to evaluate, along with their clients, if their networks may be too restrictive and, in the process, provides provider-client discussion of how and where to make relational changes. The exploration of people’s social networks on a practical and research level is a vital avenue in preventing and treating mental and physical disease in the clinical and community populations. Achieving good health indicators necessitates the use of the SCRS and other quality social network measures.

References

1. Hampton K, Goulet LS, Purcell K. Part 3: Social networking site users have more friends and more close friends. Pew Research Center. https://www.pewresearch.org/internet/2011/06/16/part-3-social-networking-site-users-have-more-friends-and-more-close-friends/. Published June 16, 2011. Accessed August 5, 2024.

2. Cohen S, Wills TA. Stress, social support, and the buffering hypothesis. Psychol Bull. 1985;98(2):310-357. doi:10.1037/0033-2909.98.2.310

3. Thoits PA. Mechanisms linking social ties and support to physical and mental health. J Health Soc Behav. 2011;52(2):145-161. doi:10.1177/0022146510395592

4. Cohen S, Janicki-Deverts D. Can we improve our physical health by altering our social networks? Perspect Psychol Sci. 2009;4(4):375-378. doi:10.1111/j.1745-6924.2009.01141.x

5. Collins HK, Hagerty SF, Quoidbach J, Norton MI, Brooks AW. Relational diversity in social portfolios predicts well-being. Proc Natl Acad Sci U S A. 2022;119(43):e2120668119. doi:10.1073/pnas.2120668119

6. The brain benefits of social connection. Psychology Today. https://www.psychologytoday.com/us/blog/the-modern-brain/202303/the-brain-benefits-of-social-connection. Accessed August 5, 2024.

7. Brothers L. The social brain: A project for integrating primate behavior and neurophysiology in a new domain. In: Foundations in Social Neuroscience. The MIT Press; 2002:367-386.

8. Han M, Jiang G, Luo H, Shao Y. Neurobiological Bases of Social Networks. Front Psychol. 2021;12. doi:10.3389/fpsyg.2021.626337

9. Manchella MK, Logan PE, Perry BL, et al. Associations between social network characteristics and brain structure among older adults. Alzheimers Dement. 2024;20(2):1406-1420. doi:10.1002/alz.13534

10. Adolphs R. The social brain: neural basis of social knowledge. Annu Rev Psychol. 2009;60(1):693-716. doi:10.1146/annurev.psych.60.110707.163514

11. Dunbar RIM. The social brain hypothesis. Evol Anthropol. 1998;6(5):178-190. doi:10.1002/(sici)1520-6505(1998)6:5<178::aid-evan5>3.0.co;2-8

12. Dunbar RIM. The social brain hypothesis and its implications for social evolution. Ann Hum Biol. 2009;36(5):562-572. doi:10.1080/03014460902960289

13. Neuroscience News. Dunbar’s number: Why the theory that humans can only maintain 150 friendships has withstood 30 years of scrutiny. Neuroscience News. https://neurosciencenews.com/dunbars-number-social-brain-19210/. Published August 28, 2021. Accessed August 5, 2024.

14. Stiller J, Dunbar RIM. Perspective-taking and memory capacity predict social network size. Soc Networks. 2007;29(1):93-104. doi:10.1016/j.socnet.2006.04.001

15. Feeney BC, Collins NL. A new look at social support: A theoretical perspective on thriving through relationships. Pers Soc Psychol Rev. 2015;19(2):113-147. doi:10.1177/1088868314544222

16. Santini ZI. The impact of social networks and social support on mental disorders and mortality. 2016. doi:10.13140/RG.2.2.17298.25282

17. Stephen G, Muldoon Orla T, Bennett Kate M. Multiple group membership, social network size, allostatic load and well-being: A mediation analysis. J Psychosom Res. 2021;151(110636):110636. doi:10.1016/j.jpsychores.2021.110636

18. Tough H, Siegrist J, Fekete C. Social relationships, mental health and wellbeing in physical disability: a systematic review. BMC Public Health. 2017;17(1). doi:10.1186/s12889-017-4308-6

19. Godman H. Can varied social interactions boost well-being? Harvard Health. https://www.health.harvard.edu/staying-healthy/can-varied-social-interactions-boost-well-being. Published April 1, 2023. Accessed August 5, 2024.

20. Ali T, Nilsson CJ, Weuve J, Rajan KB, Mendes de Leon CF. Effects of social network diversity on mortality, cognition and physical function in the elderly: a longitudinal analysis of the Chicago Health and Aging Project (CHAP). J Epidemiol Community Health. 2018;72(11):990-996. doi:10.1136/jech-2017-210236

21. Wickramaratne PJ, Yangchen T, Lepow L, et al. Social connectedness as a determinant of mental health: A scoping review. PLoS One. 2022;17(10):e0275004. doi:10.1371/journal.pone.0275004

22. Grühn AMH&. The Differential Effects of Social Integration Components on Depressive and Anxious Symptomology.; 4/2018. https://www.researchgate.net/publication/334623310.

23. Good social relationships are the most consistent predictor of a happy life. The Center for Compassion and Altruism Research and Education. https://ccare.stanford.edu/press_posts/good-social-relationships-are-the-most-consistent-predictor-of-a-happy-life/. Published October 19, 2019. Accessed August 5, 2024.

24. Relational diversity in social portfolios predicts well-being. Hbs.edu. https://www.hbs.edu/faculty/Pages/item.aspx?num=62955. Accessed August 5, 2024.

25. Gunaydin G, Oztekin H, Karabulut DH, Salman-Engin S. Minimal social interactions with strangers predict greater subjective well-being. J Happiness Stud. 2021;22(4):1839-1853. doi:10.1007/s10902-020-00298-6

26. Social determinants of health and Alzheimer’s disease and related dementias. Cdc.gov. https://www.cdc.gov/aging/disparities/social-determinants-alzheimers.html. Published May 3, 2024. Accessed August 5, 2024.

27. Kwak S, Joo WT, Youm Y, Chey J. Social brain volume is associated with in-degree social network size among older adults. Proc Biol Sci. 2018;285(1871):20172708. doi:10.1098/rspb.2017.2708

28. Von Der Heide R, Vyas G, Olson IR. The social network-network: size is predicted by brain structure and function in the amygdala and paralimbic regions. Soc Cogn Affect Neurosci. 2014;9(12):1962-1972. doi:10.1093/scan/nsu009

29. Felix C, Rosano C, Zhu X, Flatt JD, Rosso AL. Greater social engagement and greater gray matter microstructural integrity in brain regions relevant to dementia. J Gerontol B Psychol Sci Soc Sci. 2021;76(6):1027-1035. doi:10.1093/geronb/gbaa173

30. Hostinar CE, Gunnar MR. Social support can buffer against stress and shape brain activity. AJOB Neurosci. 2015;6(3):34-42. doi:10.1080/21507740.2015.1047054

31. American Psychological Association. Stress in America 2023. Apa.org. https://www.apa.org/news/press/releases/stress. Published November 2023. Accessed August 5, 2024.

32. Benavidez GA, Zahnd WE, Hung P, Eberth JM. Chronic disease prevalence in the US: Sociodemographic and geographic variations by zip code tabulation area. Prev Chronic Dis. 2024;21(230267). doi:10.5888/pcd21.230267

33. About Alzheimer’s disease. Cdc.gov. https://www.cdc.gov/aging/alzheimers-disease-dementia/about-alzheimers.html. Published July 13, 2023. Accessed August 5, 2024.