The Lonely Brain

The brain is a mysterious and intriguing organ. There are many parts that specifically control certain movement, behaviors, and bodily functions. There are various mysteries about the brain that occur today, including the idea of loneliness and isolation. Social development has a large impact on the brain’s development and its vulnerability to abnormalities such as anxiety and depression. Much of the research gathered on social development and where loneliness in the brain occurs, comes from traumatic brain injuries. Exploration of loneliness and how it develops in the brain will give insight to the development of anxiety and depression.

“Experts estimate that one-fifth of Americans define themselves as lonely”
(Henig, 2014).

Social Development

Naturally, humans are social beings. They require human contact and interaction. The development of the social brain starts in infancy and continues through adolescence and early adulthood (Grossman, 2015). The primary mechanism that begins to develop in all humans socially is the theory of mind. Theory of mind is a person’s understanding that other people have goals, desires, and attitudes other than their own. Theory of mind can be a building block for a person’s social brain and it is developed through other factors. One of these factors is a major focus of Grossman’s (2015), joint engagement. It is described by the “The primary cues that infants use to detect joint engagement are referential visual, auditory, or body cues (gaze, voice, and body direction/orientation)” (Grossman, 2015). Simple human interaction early in life is essential for infants to develop social skills before they can communicate verbally. These interactions form the foundation of the social brain. Joint engagement is one of several essential ingredients to develop a social brain. In addition to the development of joint engagement, predictability becomes part of second nature as the social brain develops. Predictability refers to the anticipation of someone else’s actions or goals (Grossman, 2015). This relates back to the theory of mind and being aware that other people have differing goals and aspirations. As infants, humans will develop a knowledge and memory of certain actions which then become predictable to them. They are able to more easily guess what will come next and actively participate in social interaction.

Figure 1

After infancy, development continues and is changed throughout adolescence. In this TED talk, Sarah-Jayne Blakemore describes the fascination of the social brain in her lab. Blakemore describes the social brain as the networking regions in the brain that control our interactions with others and how we interpret others’ behavior, expressions, and attitudes (Blakemore, 2012). In adolescence and adulthood, social development occurs in the prefrontal cortex. In the talk, Blakemore elaborates that “activity in this medial prefrontal cortex area decreases during the period of adolescence” (Blakemore, 2012).

Figure 2

This would account for the stereotype of adolescents exemplifying risky and deviant behaviors. Their brains are different during development and go through various changes. Blakemore addresses the difference in thought process when stating, “adolescents and adults use a different mental approach, a different cognitive strategy, to make social decisions” (Blakemore, 2012).

Anatomy wise, there are many parts of the brain that involve social processing. Not only are there many parts, but they are all scattered throughout the brain and not in a central region. Beauchamp and Anderson (2010) refer to higher order social skills being located in the frontal regions of the brain (Beauchamp and Anderson, 2010). This would include the theory of mind complex mentioned earlier in the text. In addition to higher order social skills, facial recognition is something essential that develops when humans are infants. Facial recognition has been linked to the fusiform gyrus, which is located in the occipital lobe. On the other hand, recognizing others’ emotions is found in the control of the amygdala (Beauchamp and Anderson, 2010). As highlighted in figure 2, most of the areas are scattered throughout the brain and control other functions as well as social development.

Nature vs. Nurture

In addition to neuropsychological reasoning, social development depends a lot on nature and nurture of a person when developing. Much of the research indicates that social development is reliant upon the raising of a child and support they receive. Factors of environment such as family, social support, and attachment are essential in the development in the social brain. Interestingly enough, “socioeconomic status (SES) dictates the frequency and quality of social interactions and opportunities, with children in deprived social contexts disadvantaged in terms of their access to stimulating social environments” (Beauchamp and Anderson, 2010). If someone is exposed to more social situations early in development, they will be more social people.

Disruptions in the development of social skills discussed can lead to psychological distress, reduced self-esteem, and isolation or loneliness.


Figure 3

As mentioned prior, humans are social animals by nature and “loneliness is thought to arise because an innate need to belong to a group is unmet; therefore, loneliness signals a need to form a meaningful connection with others, motivating the development and maintenance of social relationships that facilitate survival” (Lim, Rodebaugh, Zyphur, & Gleeson, 2016). There are various factors that contribute to loneliness as shown in the picture above. One common misconception of loneliness is that quantity in one’s support system is more important than the quality of those relationships. Loneliness has a lot to do with perceived social support and interestingly enough, “Both human and animal research suggests that loneliness (perceived isolation) reflects the discrepancy between the preferred and actual social conditions rather than objective social isolation” (Cacioppo et al., 2014) Loneliness is seen as a problem or a result of an abnormality in a person’s social ability and has been argued as a precursor and as a result of many mental health issues.

In the ted talk above, John Cacioppo supports the evidence that visual receptors will view images more negative if a brain is lonely (Cacioppo, 2014). In a study exploring the effects of loneliness on mortality, “Evidence from behavioral and functional magnetic resonance imaging (fMRI) studies also supports the notion that loneliness increases attention to negative social stimuli (e.g., social threats) and to self-preservation”(Cacioppo, Capitanio, & Cacioppo, 2014). Throughout this study, it was found that people who were lonely, did not gain energy from sleeping, which is problematic because sleep is the body’s way of restoring itself. In addition, he views loneliness as a biological warning sign similar to hunger or thirst. He describes loneliness as a warning that there is damage to a person’s social health and ability. In Cacioppo’s (2014) Ted Talk, he displays a graph that depicts loneliness as more deadly that excessive drinking, obesity, and air pollution (Cacioppo, 2014). Human’s bodies begin to go into a self preservation mode when feeling lonely which is their way of escaping problems or threats.

Figure 4

The picture on the left is a representation of neuron synapse release to cause the feeling of loneliness. The bottom portion relates to the visual cortices and why they view things negatively when feeling lonely. Photoinhibition is the term to describe our brains viewing situations and events negatively due to the feeling of isolation. There is more response to social stimuli in a normal brain compared to the lonely brain.

A better picture of what areas are associated with loneliness and isolation is featured in figure 5. The prefrontal cortex, Temporo-parietal junction, striatum, amygdala, hippocampus, and the visual cortex are labeled clearly as areas in relation to the lonely brain. Portion B displays the physiological effects of loneliness such as high blood pressure, HPA activation (the endocrine glands releasing in response to stress), low immunity, and decreased quality in sleep. Section D displays the effects that isolation and loneliness has on the specific brain structures involved.

Figure 5 (Cacioppo et al., 2014)

The brain functions differently when experiencing loneliness and isolation. Key brain structures are disturbed and decreased in functions that have to do with the social brain. With all of the areas in the brain highlighted that are associated with loneliness and isolation, it is essential to explore the outcomes in the change of brain functionality.

Outcomes of Loneliness and Isolation

Loneliness has negative health outcomes including mental health, sleep disorders, immune system deficiencies, and increased levels of stress. Loneliness in accordance with anxiety and depression has a interchangeable relationship. Some researchers beleive that loneliness causes these mental disorders. On the other hand, some neuro scientists believe that loneliness is a sign that anxiety or depression is occurring in the brain.

Depression has been addressed as an outcome of loneliness. The main difference between the two described by Lim and associates (2016) is that “loneliness relates to how one negatively perceives social relationships whereas depressive symptoms relate to how one feels more generally” (Lim et al., 2016). Depression as described by these researchers is more of an emotional feeling and loneliness is the perception of social relationships that cause the feeling of isolation. From this research, it could be concluded that loneliness is simply a symptom of depression. Furthermore , the research found that if loneliness was reduced for a long period of time it reduced overall depressive symptoms over time.

In a research study conducted by Lim, Rodebaugh, Zyphur, & Gleeson (2016), tested people using loneliness and depression scales with a follow up years later. Their findings determined that high feelings of loneliness and isolation are predictors for depression and anxiety later on. On the other hand anxiety was discussed as a precursor to higher levels of loneliness (Lim, Rodebaugh, Zyphur, & Gleeson, 2016). Social anxiety can be described as the fear of interactions with others and worry about minor situations. This mental disorder encourages higher rates of loneliness because it causes people to withdraw from social situations which causes them to be more lonely. The culmination of all of these symptoms together than begins to physically affect people’s sleep, fatigue, immune system, and stress levels. All of these factors weighing on a person can be detrimental in the physiological effects.

Limitations in this research includes the age difference among participants. The age would effect the level of development that the brain has accomplished and the vulnerability of the brain. With disruptions in social development, loneliness can occur and lead to larger problems such as depression and anxiety. The development of the social brain is essential early on in life and can be determined by the environment and care of a child. The lonely brain develops when the perception of social support is low and this occurs due to disturbances in development. Many brain mechanisms are involved in the feeling of loneliness and disrupts proper functioning of the brain. The stress of loneliness causes disturbances in sleep, hormone imbalance, and high blood pressure. This disruption occurs and if it continues for a long period of time can result in more serious mental disorders.


Beauchamp, M. H., & Anderson, V. (2010). SOCIAL: An integrative framework for the development of social skills. Psychological Bulletin, 136(1), 39–64.

Blakemore, S. (2012, June). Retrieved December 02, 2017, from

Cacioppo, S., Capitanio, J. P., & Cacioppo, J. T. (2014). Toward a neurology of loneliness. Psychological Bulletin, 140(6), 1464–1504.

Grossmann, T. (2015). The development of social brain functions in infancy. Psychological Bulletin, 141(6), 1266–1287.

Lim, M. H., Rodebaugh, T. L., Zyphur, M. J., & Gleeson, J. F. M. (2016). Loneliness over time: The crucial role of social anxiety. Journal of Abnormal Psychology, 125(5), 620–630.

Matthews, G. A., Nieh, E. H., Vander Weele, C. M., Halbert, S. A., Pradhan, R. V., Yosafat, A. S., … Tye, K. M. (2016). Dorsal Raphe Dopamine Neurons Represent the Experience of Social Isolation. Cell, 164(4), 617–631.

Ph.D, G. W. (n.d.). 10 Surprising Facts About Loneliness. Retrieved December 1, 2017, from

The Science of Loneliness. (n.d.). Retrieved December 2, 2017, from