As a nostalgist in the truest sense, I found the following of particular interest to me...There is comfort in knowing that I am not alone.

SOUTHAMPTON, England — Not long after moving to the University of Southampton, Constantine Sedikides had lunch with a colleague in the psychology department and described some unusual symptoms he’d been feeling. A few times a week, he was suddenly hit with nostalgia for his previous home at the University of North Carolina: memories of old friends, Tar Heel basketball games, fried okra, the sweet smells of autumn in Chapel Hill.

“I told him I did live my life forward, but sometimes I couldn’t help thinking about the past, and it was rewarding,” he says. “Nostalgia made me feel that my life had roots and continuity. It made me feel good about myself and my relationships. It provided a texture to my life and gave me strength to move forward.”

The colleague remained skeptical, but ultimately Dr. Sedikides prevailed. That lunch in 1999 inspired him to pioneer a field that today includes dozens of researchers around the world using tools developed at his social-psychology laboratory, including a questionnaire called the Southampton Nostalgia Scale. After a decade of study, nostalgia isn’t what it used to be — it’s looking a lot better.

Nostalgia has been shown to counteract loneliness, boredom and anxiety. It makes people more generous to strangers and more tolerant of outsiders. Couples feel closer and look happier when they’re sharing nostalgic memories. On cold days, or in cold rooms, people use nostalgia to literally feel warmer.

Nostalgia does have its painful side — it’s a bittersweet emotion — but the net effect is to make life seem more meaningful and death less frightening. When people speak wistfully of the past, they typically become more optimistic and inspired about the future.

“Nostalgia makes us a bit more human,” Dr. Sedikides says. He considers the first great nostalgist to be Odysseus, an itinerant who used memories of his family and home to get through hard times, but Dr. Sedikides emphasizes that nostalgia is not the same as homesickness. It’s not just for those away from home, and it’s not a sickness, despite its historical reputation.

Nostalgia was originally described as a “neurological disease of essentially demonic cause” by Johannes Hoffer, the Swiss doctor who coined the term in 1688. Military physicians speculated that its prevalence among Swiss mercenaries abroad was due to earlier damage to the soldiers’ ear drums and brain cells by the unremitting clanging of cowbells in the Alps.

In the 19th and 20th centuries nostalgia was variously classified as an “immigrant psychosis,” a form of “melancholia” and a “mentally repressive compulsive disorder” among other pathologies. But when Dr. Sedikides, Tim Wildschut and other psychologists at Southampton began studying nostalgia, they found it to be common around the world, including in children as young as seven-years-of-age (who look back fondly on birthdays and vacations).

“The defining features of nostalgia in England are also the defining features in Africa and South America,” Dr. Wildschut says. The topics are universal — reminiscences about friends and family members, holidays, weddings, songs, sunsets, lakes. The stories tend to feature the self as the protagonist surrounded by close friends.

Most people report experiencing nostalgia at least once a week, and nearly half experience it three or four times a week. These reported bouts are often touched off by negative events and feelings of loneliness, but people say the “nostalgizing” — researchers distinguish it from reminiscing — helps them feel better.

To test these effects in the laboratory, researchers at Southampton induced negative moods by having people read about a deadly disaster and take a personality test that supposedly revealed them to be exceptionally lonely. Sure enough, the people depressed about the disaster victims or worried about being lonely became more likely to wax nostalgic. And the strategy worked: They subsequently felt less depressed and less lonely.

Nostalgic stories aren’t simple exercises in cheeriness, though. The memories aren’t all happy, and even the joys are mixed with a wistful sense of loss. But on the whole, the positive elements greatly outnumber the negative elements, as the Southampton researchers found by methodically analyzing stories collected in the laboratory as well as in a magazine named Nostalgia.