What happens in the brain when you’re alone

So what exactly goes on in the mind when we’re alone, and why do so many people both crave and fear solitude? “The brain is always on,” says Dr. Marcus Raichle, professor of radiology and neurology at Washington University. “It’s running at about 95 percent of its maximum most of the time. It’s got this tremendous background activity. So then the big question that comes up, is what in the dickens is your brain doing?”

In the late 1990s, Raichle and his colleagues were studying the parts of the brain involved in various tasks when they were surprised to discover that several areas actually ramp up activity when there are no external tasks or distractions. These interconnected parts of the brain all focus on “self-referential” processes, such as recalling personal memories to navigate the future, feeling emotions, and evaluating incoming information. The researchers named these areas of the brain working in tandem the “default mode network.” “You add this all together, and you see there’s something very central, something that has to do with the fact that I have a self—it’s me,” says Raichle. When external distractions go away and we allow our minds to wander, the default mode network is working at full capacity and may play an important role in forming our sense of identity. Being alone can also free the mind from a phenomenon called the spotlight effect. When in public, we tend to overestimate the extent to which others notice our accomplishments and mistakes, and when alone, our brains can stop imagining that our actions are on full display. “As one's experience of viewing a painting in a museum changes when another person walks up, our subjective experience is influenced by the slightest interaction with another person,” wrote Christopher Long in a 2003 review of research on the benefits of solitude. “We become conscious not only of the object we are viewing but also of ourselves as viewers.” In a 2012 New York Times trend piece about living alone, people admitted to developing a variety of quirks when they no longer had roommates—from talking to the cat to singing in the shower.

Despite the benefits of solitude, being left truly alone with our thoughts can be uncomfortable or even stressful. In one study, people were left alone for 6 to 15 minutes with no distractions—except a device that administered electric shocks. To the researchers’ surprise, nearly 70 percent of men and 25 percent of women chose to shock themselves. In another version of the study, participants were told to sit alone in their home with their thoughts for 10 to 15 minutes. More than half confessed to cheating by getting up from the chair or distracting themselves with phones or music. Like many good things, too much solitude can be damaging. One study found that older people who are socially isolated have a 26 percent higher mortality rate than their socially connected peers—although the researchers attributed this more to the physical complications of isolation than the actual feeling of loneliness. Extended isolation can raise stress levels and affect the way the mind interprets stimuli. One study used an EEG (a device that measures electrical activity of the brain) to measure participants’ reactions to positive and negative words—some of which had social connotations like “accepted” and “unwanted.” Lonely people’s brains lit up much more quickly than those of their peers when shown socially negative words, suggesting their brains have adapted to pay heightened attention to social threats and dangers.

Sarah Shourd was one of three American hikers who were apprehended by Iranian border guards on the Iraq-Iran border in 2009 and detained until 2011. She later described her experience of solitary confinement in the New York Times: “After two months with next to no human contact, my mind began to slip. Some days, I heard phantom footsteps coming down the hall … In the periphery of my vision, I began to see flashing lights, only to jerk my head around to find that nothing was there.” Shourd’s frightening hallucinations are not surprising. A 2000 study found that prisoners in solitary confinement are subject to extreme stress, which causes them to develop psychiatric disorders at a much higher rate than those housed in the general prison population. Too much solitude can actually cause people to lose their minds. Alan Kay, who won the History Channel’s survival reality show “Alone” by spending 56 days in isolation on Vancouver Island, experienced these effects to a lesser extent. “You start to see these human characteristics superimposed on the vocalizations of these animals,” he told Thrillist. “When I heard seagulls, they sounded to me like my children when they were discontent. When I heard ducks, they sounded like old men arguing with each other.” One of the reasons solitude is difficult to describe and measure is because it is experienced differently by different people—and even by the same person in different situations. “The observation that people claim to want more solitude and yet often experience solitude negatively is not as contradictory as it might seem,” wrote Christopher Long. “People often idealize conditions that, if realized, they would find intolerable. But despite potential difficulties associated with solitude, the research and theory … suggest that achieving a capacity for positive solitude is a desirable goal.”