by Ivo I. Gyurovski
Humans are intensely social, because we evolved to function in groups. Our tall, weak, and hairless bodies do not protect us from the exigencies of the environment. The evolutionary advantage of our species is rooted in its obligatory interdependence, where success is predicated on the ability to plan, reason, and work together. The outbreak of COVID-19 has impacted every aspect of life. In this article, I explore how social distancing and stay-at-home measures can impact individuals’ behavior and mental processes.
The Science of Isolation
Historically, humans have tackled big and difficult questions through the sharing of individually possessed knowledge as well as the collective efforts of groups of individuals, making our history the product of co-evolution between genetic endowment and social structure.
As a result, human sociality encompasses those characteristics most associated with group identity, such as cooperation, group loyalty, adherence to socially learned norms, and fear of social isolation.
Yet the current pandemic has left many of us isolated at home alone, as 28 percent of all U.S. households are single-person. Others are quarantined with family members, but nonetheless experience a variation of loneliness, unable to spend time with friends, colleagues, or extended family. Therefore, it is sensible to ask how social isolation shapes the way we think, feel, and act.
Our brains have evolved to be highly responsive to aversive signals that are designed to motivate survival behavior. For example, when the brain detects changes in energy (e.g. low levels of sugar) it correspondingly triggers a cascade of metabolic and biological processes aimed at restoring energy homeostasis (e.g. eating and feeling satiety).
Social isolation represents another aversive signal. In fact, an overlapping set of brain regions–dorsal anterior cingulate cortex; insular cortex—is responsible for processing both the emotional response to physical pain and the social pain that comes from being isolated from others. Unlike in the case of hunger, however, where aversive signaling makes us engage in behaviors that make us less hungry, the aversive signaling in the case of social isolation does not trigger behaviors that make us less isolated.
Paradoxically, experiencing social isolation or perceived loneliness brings about a vigilant state of mind, where our brain is preoccupied with self-preservation in negative circumstances. We become more focused on ourselves and our own needs, and we allocate more attention to potentially negative social situations, such as competition or conflict. 
To some extent this occurs because of changes in activation of the temporoparietal junction (TPJ). This region enables mentalizing or theory of mind, which is our ability to peek into the minds of others in order to appreciate their point of view. The greater the loneliness people experience, the less activation is observed in the TPJ, meaning that it is that much harder for people to engage in perspective taking, empathy, and shared experiences.
The brain region associated with the processing of rewards and appetitive behavior, the ventral striatum, also responds strongly to pleasant social stimulation—essentially, the lonelier the brain, the less activation that occurs in the ventral striatum. This means that in a state of isolation we experience diminished pleasure from typically pleasant social experiences.
Experimental manipulations have shown that isolation also changes the way we view others. We tend to form more negative impressions of others, and we fear negative evaluation by others. Interestingly, the capacity of our social skills does not change, but isolation and loneliness along with the corresponding self-preservation focus make us less likely to express the social skills that usually characterize our behavior. We are more likely to find faults in others and act more coldly towards them.
Changes in the way we form impressions of others impact not only interpersonal interactions but also intergroup relations. At the best of times, we have problems with stereotypes and prejudice. The current pandemic will exacerbate not only individual prejudices, but also issues of structural inequality, such as evidence that shows minorities and people of color are disproportionately affected by the virus.
Coping with Isolation
It is also important to watch for issues related to mental health. For many of us it has been hard to adjust to the new normal. We are not only stuck at home but also confronted with having to live together in a confined space. Having to juggle occupational and family obligations can be a challenge anytime, but doing so currently will bring additional stress. In many households, technology and internet access are limited, so coordinating their use may lead to frustration. Not only are our home and work environments drastically different but also the number one topic of conversation and on the news is the pandemic. Therefore, people are much more likely to experience stress, frustration, negative moods, and anger. We are likely to observe increases in the incidences of both anxiety and depression.
Nevertheless, there might be a light at the end of the pandemic tunnel. People do not consistently act either selfishly or altruistically. The evolution of human sociality favors a balance between self-oriented and group-oriented motivations. We are all united in how isolated we are.