Together: The Healing Power of Human Connection in a Sometimes Lonely World

Based upon the research of Dr. Robin Dunbar, an evolutionary psychologist, Murthy posits that social connections occur primarily within three “circles.” The inner circle is comprised of a handful of one’s closest friends and confidantes, including romantic partners and family members to which one feels close. These relationships promote intimate connection. The middle circle includes casual relationships, such as friends from camps, clubs, schools, and one’s neighborhood; the middle circle encompasses up to 150 people. Middle-circle relationships prevent relational loneliness. Outer circle relationships include colleagues as well as acquaintances, such as relationships formed through community work or at church. The outer circle of connection prevents collective loneliness and may expand one’s social network to about 500 people.

Hypervigilance occurs when the sympathetic nervous system reacts to a perceived threat in one’s environment. In a hypervigilant state, one experiences physical reactions due to the activation of the hypothalamic-pituitary-adrenal axis, which releases hormones, such as epinephrine, that dilate the pupils, elevate the heart rate, and increase blood sugar levels. Murthy draws upon Dr. John Cacioppo’s evolutionary theory of loneliness, which suggests that hypervigilant reactions to isolation—such as feeling anxious—are hardwired into the human nervous system. While isolation from one’s group is no longer the lethal threat it was for early humans, these imprinted tendencies still give rise to stress hormones, cardiac stress, and other biological processes that impact physical and mental health.

Murthy defines isolation as “the objective physical state of being alone and out of touch with other people” (25). The author identifies isolation as a risk factor for loneliness because people are more likely to feel lonely when they don’t interact with others. Murthy also notes that isolation leads to hypervigilance, which leads to a stress response from the sympathetic nervous system; in this way, isolation is connected to chronic health conditions, as well as mental health concerns.

According to Murthy, loneliness is “the subjective feeling that you’re lacking the social connections you need. It can feel like being abandoned, stranded, or cut off from others, even if you’re surrounded by other people” (24). Loneliness can manifest itself as alienation, sadness, anger, and other negative emotional states. Murthy describes three types of loneliness: intimate, or the lack of close friends and confidants; relational, or the lack of social companionship and support; and collective, or the lack of a community with a shared sense of purpose.

Perceptual narrowing is a process that reduces infants’ sensitivity to certain stimuli, such as the race or ethnicity represented in faces. Babies are born with the capacity to bond with anyone and learn any language. The capacity to differentiate among faces representing different races, or to learn a new language, reduces by the age of three months, as infants learn to home in and focus on caregivers’ characteristics. Perceptual narrowing evolved to create a sense of belonging and protect group members from outsiders.

According to Dr. Matthew Lieberman, self-processing refers to the engagement of the medial prefrontal cortex when one thinks about the self, such as deciding what to wear, thinking about one’s favorite hobby, or remembering one’s past. Self-processing helps to shape a person’s identity, but Murthy notes that the process is not actually totally self-centered: The medial prefrontal cortex is also engaged when one thinks about or socializes with others. Murthy uses self-processing as a way of demonstrating how the human brain is hardwired to seek social connection.