Do you have wistful memories of the cookies that came from your grandmother’s oven? Do you enjoy recalling the jokes and pranks that you and your school friends used to find hilarious? On a restless night, does the whoosh of a train on a long-ago journey linger in your mind? If your recollections sometimes evoke a sentimental yearning for the past, then you know what it means to experience nostalgia.

You are in good company, too. In a 2006 study conducted at the University of Southampton in England, 79 percent of the 172 students surveyed said that they have nostalgic thoughts at least once a week; 16 percent reported having such moments every day. Nostalgia is not limited to any culture, stage of life or state of mental health. Our Southampton team has found the emotion in healthy adults and children, as well as patients suffering from dementia.

What may surprise you, though, is that nostalgia has an important function. Rather than being a waste of time or an unhealthful indulgence, basking in memories elevates mood, increases self-esteem and strengthens relationships. In short: nostalgia is a source of psychological well-being.

Systematic research into nostalgia was unknown until about 30 years ago, but physicians have used the term since the 17th century. It derives from the Greek words nstos (“return”) and lgos (“pain”), so that nostalgia means, literally, the suffering that results from a desire for return—to a place, to a time, to a way of life. Swiss physician Johannes Hofer coined the term to describe the behavior of Swiss mercenaries in the service of European monarchs. These soldiers were reportedly plaguedby an obsessive longing for their homeland, which manifested itself in hysterical fits of crying, anxiety, heart palpitations, diminished appetite and insomnia. Hofer considered nostalgia a disease.

In the 19th century nostalgia took on a Freudian cast. Psychoanalysts interpreted sentimental yearning as a pathological form of melancholy. Some called it “immigrant psychosis,” a now discredited disorder of recently transplanted people; others attributed it to unresolved grief and depression. A number of these dour characterizations remained in currency as recently as the 1980s.

Stories of Redemption The turning point in psychologists’ understanding of nostalgia came in 1979, when American sociologist Fred Davis discovered that people associate nostalgia with positive words such as “warm,” “old times” and “childhood”; in contrast, homesickness has predominantly sad connotations. Yet it was not until 2006 that scientists first examined nostalgic thoughts in detail. A research team that included one of us (Sedikides) and that was led by Dutch psychologist Tim Wildschut, our colleague at Southampton, analyzed articles published in Nostalgia, an American magazine dedicated to portraying life in the mid-20th century. The investigators next asked students to summon a nostalgic memory and describe it as precisely as possible. Then they categorized the students’ statements by subject matter and compared them with a similar breakdown of the magazine articles.

The analyses of the magazine articles and the students’ responses both yielded similar results. Nostalgia, it appears, is a specific form of autobiographical memory: most people give themselves the starring role in nostalgic flashbacks. These glances back often focus on relationships: a third of nostalgic thoughts involve other people. And nostalgic memories quite often feature a so-called redemption theme or mastery sequence—a story line that begins with a bad experience out of which something good ensues. For example, one of our study subjects wrote: “My Nan died that weekend, and even though it was awful, it was a type of relief for my Nan and us. When I look back at this in my mind, I feel so proud of my Mum and the way she coped; it showed her immense love and devotion to her own mother.” Another example of an experience that might become a nostalgic memory: an apprehensive student calls the university for his exam results, learns that he passed, and feels tremendous joy and relief. When describing nostalgic memories, people were much less apt to report promising beginnings and disastrous ends.

Because mastery sequences occurred much more frequently than deterioration sequences, the Wildschut team classified nostalgia as a primarily positive emotion. And the spontaneous self-assessments of the test subjects confirmed this conclusion: they perceived most of their memories as pleasant. This statement from one study participant neatly sums up the positive biographical and social nature of nostalgic memory: “I felt like I was really important to him and that no one else was as close. We had our own sort of ‘code’ and would talk to each other so no one else knew what we were saying.”

Thoughts Born of Sadness Like any emotion, nostalgic feelings must be triggered by some external or internal event. One way to investigate its triggers is simply to ask people to describe the circumstances and mental states under which they experience the emotion. When Wildschut and his team put this question to participants in their study, the most commonly cited precursor of nostalgia, mentioned by 38 percent of the respondents, was dysphoria—a depressed, anxious or irritable mood—and 34 percent of the dysphoric participants cited loneliness as their trigger.

To test whether nostalgia does occur more frequently when a person is sad, the Wildschut team invited 62 psychology undergraduates to its lab. The subjects were randomly assigned to read one of three newspaper articles. A third of the subjects read an article about the birth of a polar bear at a zoo, selected to put them in a happy frame of mind. Another  third read a depressing article, about the tsunami that hit Asia and Africa in December 2004. The remaining subjects read an article with neutral content, about the landing of the Huygens probe on Titan, one of Saturn’s moons. The volunteers were then asked to report how much they missed certain aspects of their past. Among the choices were “the way people were,” “holidays I went on,” “my pets,” “past TV shows and movies,” and “feelings I had.” Those who had read the sad article clung more tenaciously to the past than did those from the other groups—particularly to thoughts of people they were close to: their family, someone they loved, their friends.

Feelings of abandonment can also trigger nostalgia. In a later experiment, the Wildschut team asked the test subjects to fill out a questionnaire and told them it had been designed to assess how lonely they were. The researchers then gave the participants bogus feedback about their responses. Half of the volunteers were told that their answers reflected a sense of abandonment; the other half were told the opposite. Manipulated this way, both groups filled out a nostalgia checklist to see how much they missed 18 elements of their past, such as family, schools and childhood toys.

The results were almost identical to the findings of the previous study. The test subjects who were convinced they felt lonely showed the same yearning for past relationships as did the people who had read the sad article.

These studies yield a consistent picture: people tend to become nostalgic when they feel low-spirited or lonely. But why should this be the case? Does sadness lead people to dwell unproductively on the contrast between their present situation and earlier, happier times? Or do people use nostalgia as a kind of mood enhancer? We decided to find out.

Connecting to Others In 2006 the Southampton team conducted an experiment focusing on how nostalgia affects psychological well-being. Wildschut and his colleagues first asked the test subjects to recall circumstances that were particularly tinged with nostalgia. Then, as a measure of how these reveries affected their disposition, participants reported their current emotions, specifically the degree to which they were feeling “loved,” “protected,” “significant,” “high self-esteem,” “happy,” “content,” “sad” and “blue.” The most nostalgic of the subjects showed high scores in the three measures of happiness, social integration and self-esteem. In other words, nostalgic thinking—which we had earlier found was often triggered by sadness and feelings of disconnection—breeds happier moods.

Our co-workers suspected that one factor in particular accounted for the positive effect of nostalgia on mood: the feeling of social integration. We set out to test whether nostalgia makes people feel a sense of belonging. In our laboratory, we asked participants to evaluate their social competence in three areas: their adeptness in building relationships; their openness with other people about their feelings; and their ability to give a friend emotional support. The participants most likely to engage in nostalgic thinking did better in all three measures of social skills than those in the control group.

This social-glue effect appears to be a universal phenomenon and not simply an artifact of how nostalgia plays out in Western culture. For a 2008 study the Southampton team collaborated with researchers at Sun Yat-sen University in Guangzhou, China. The experimental setup was similar to the earlier study in Southampton, except now with Chinese undergraduates as the test subjects. The researchers asked some of the students to indulge in nostalgic reverie and others to conjure an ordinary memory. The participants then assessed how much support they thought they could count on from friends and family if times grew hard. Once again the results showed that the simple act of recalling a nostalgic memory was enough to make people more certain of the support of their friends. Yearning for the past seems to increase our sense of social support, independent of cultural background.

Happy Endings “To be able to look back on one’s past life with satisfaction is to live twice,” wrote first-century Roman poet Marcus Valerius Martial. And indeed, not only can nostalgia help people recover from sadness and isolation, but golden memories can inoculate against future bad moods. In a 2008 study psychologist Clay Routledge of North Dakota State University and the Southampton team confronted volunteers with the thought of their own death to see if nostalgia could allay this archetypal fear.

In a three-part experiment, the researchers asked half the volunteers to write a short essay about a particular circumstance that made them feel nostalgic. The other participants wrote about a commonplace event from their past. Next, participants were shuffled into two new groups. The first group was asked to answer two questions in writing: “What emotion triggers the thought of your own death?” and “What, in your opinion, occurs in your body when you die, and what happens after you have died?” The second group was asked to write about failing an important test in the past.

Finally, participants were asked to work on a task that tests the extent to which the psyche is unconsciously preoccupied with the question of death. They had to take 28 word fragments (such as “coff”) and suggest a complete word that incorporated the fragment. Six of these fragments could be either part of a word that has something to do with dying (“coffin”) or part of a more neutral term (“coffee”).

Participants who had earlier been pondering their own deaths were more apt to select morbid words. This tendency, though, was not evident among the nostalgics. Those who at the start of the study had reflected on beautiful memories completed the word fragments in a manner that was similar to the participants who in the second part of the experiment had looked back on their flunked exam.

As effective as nostalgia appears to be as a natural mood enhancer, for one large group the benefit can be more elusive: people with depression. A 2007 investigation led by psychologist Jutta Joormann of the University of Miami showed that in contrast to healthy people, patients who suffer from severe depression do not become happier when they think about happy moments from their school days. In fact, exactly the opposite occurs.

The reason appears to be that depressed people do not easily identify with the happier self of their past. A 2008 study led by one of us (Gebauer) at Cardiff University in Wales found that chronically sad people perceive very little similarity between the positive “I” of their memory and their negative self-perception in the present. Instead they believe that this positive “I” is located in a remote past and conclude, “In comparison to the person I was back then, I’m an absolute loser today.” So depressed people can feel even worse after recalling a happy memory.

But not all happy thoughts are equal. Indeed, nostalgia has characteristics that make it different from other positive memories, and these distinctions point to ways in which nostalgia could help depressives. According to the studies by Wildschut and his colleagues, nostalgic recollections are more multifaceted, complex and vivid than mere positive memories. The redemption sequence they often contain could potentially hearten chronically unhappy people; after all, if something turned out well in the past, it could happen that way again.

We are preparing a study to test whether this is the case. We intend to ask both depressed and healthy people to summon three images from the past: an image of themselves as they were five years ago, cast solely in terms of their positive attributes; an image from the same time that casts them solely in terms of their negative attributes; and a purely nostalgic episode, involving a sense of yearning for the past and a mastery or redemption sequence. We expect that only the nostalgic episode will help improve the self-image of people who are depressed, whereas the other two kinds of memories, including the positive one, may worsen it.

For most of us, it seems, nostalgia not only fosters a sense of well-being but, like armor shielding the mind from dark thoughts, protects against psychological onslaughts in the future. Our research shows that nostalgic memories are especially detailed and vivid, in part because we tend to nurture them more assiduously than other memories. Indeed, the more we see how nostalgia provides balm for the wounded psyche, the farther the view of nostalgia as a pathological weakness recedes into the distant, and in this case less rosy, past.

You are in good company, too. In a 2006 study conducted at the University of Southampton in England, 79 percent of the 172 students surveyed said that they have nostalgic thoughts at least once a week; 16 percent reported having such moments every day. Nostalgia is not limited to any culture, stage of life or state of mental health. Our Southampton team has found the emotion in healthy adults and children, as well as patients suffering from dementia.

What may surprise you, though, is that nostalgia has an important function. Rather than being a waste of time or an unhealthful indulgence, basking in memories elevates mood, increases self-esteem and strengthens relationships. In short: nostalgia is a source of psychological well-being.

Systematic research into nostalgia was unknown until about 30 years ago, but physicians have used the term since the 17th century. It derives from the Greek words nstos (“return”) and lgos (“pain”), so that nostalgia means, literally, the suffering that results from a desire for return—to a place, to a time, to a way of life. Swiss physician Johannes Hofer coined the term to describe the behavior of Swiss mercenaries in the service of European monarchs. These soldiers were reportedly plaguedby an obsessive longing for their homeland, which manifested itself in hysterical fits of crying, anxiety, heart palpitations, diminished appetite and insomnia. Hofer considered nostalgia a disease.

In the 19th century nostalgia took on a Freudian cast. Psychoanalysts interpreted sentimental yearning as a pathological form of melancholy. Some called it “immigrant psychosis,” a now discredited disorder of recently transplanted people; others attributed it to unresolved grief and depression. A number of these dour characterizations remained in currency as recently as the 1980s.

Stories of Redemption The turning point in psychologists’ understanding of nostalgia came in 1979, when American sociologist Fred Davis discovered that people associate nostalgia with positive words such as “warm,” “old times” and “childhood”; in contrast, homesickness has predominantly sad connotations. Yet it was not until 2006 that scientists first examined nostalgic thoughts in detail. A research team that included one of us (Sedikides) and that was led by Dutch psychologist Tim Wildschut, our colleague at Southampton, analyzed articles published in Nostalgia, an American magazine dedicated to portraying life in the mid-20th century. The investigators next asked students to summon a nostalgic memory and describe it as precisely as possible. Then they categorized the students’ statements by subject matter and compared them with a similar breakdown of the magazine articles.

The analyses of the magazine articles and the students’ responses both yielded similar results. Nostalgia, it appears, is a specific form of autobiographical memory: most people give themselves the starring role in nostalgic flashbacks. These glances back often focus on relationships: a third of nostalgic thoughts involve other people. And nostalgic memories quite often feature a so-called redemption theme or mastery sequence—a story line that begins with a bad experience out of which something good ensues. For example, one of our study subjects wrote: “My Nan died that weekend, and even though it was awful, it was a type of relief for my Nan and us. When I look back at this in my mind, I feel so proud of my Mum and the way she coped; it showed her immense love and devotion to her own mother.” Another example of an experience that might become a nostalgic memory: an apprehensive student calls the university for his exam results, learns that he passed, and feels tremendous joy and relief. When describing nostalgic memories, people were much less apt to report promising beginnings and disastrous ends.

Because mastery sequences occurred much more frequently than deterioration sequences, the Wildschut team classified nostalgia as a primarily positive emotion. And the spontaneous self-assessments of the test subjects confirmed this conclusion: they perceived most of their memories as pleasant. This statement from one study participant neatly sums up the positive biographical and social nature of nostalgic memory: “I felt like I was really important to him and that no one else was as close. We had our own sort of ‘code’ and would talk to each other so no one else knew what we were saying.”

Thoughts Born of Sadness Like any emotion, nostalgic feelings must be triggered by some external or internal event. One way to investigate its triggers is simply to ask people to describe the circumstances and mental states under which they experience the emotion. When Wildschut and his team put this question to participants in their study, the most commonly cited precursor of nostalgia, mentioned by 38 percent of the respondents, was dysphoria—a depressed, anxious or irritable mood—and 34 percent of the dysphoric participants cited loneliness as their trigger.

To test whether nostalgia does occur more frequently when a person is sad, the Wildschut team invited 62 psychology undergraduates to its lab. The subjects were randomly assigned to read one of three newspaper articles. A third of the subjects read an article about the birth of a polar bear at a zoo, selected to put them in a happy frame of mind. Another  third read a depressing article, about the tsunami that hit Asia and Africa in December 2004. The remaining subjects read an article with neutral content, about the landing of the Huygens probe on Titan, one of Saturn’s moons. The volunteers were then asked to report how much they missed certain aspects of their past. Among the choices were “the way people were,” “holidays I went on,” “my pets,” “past TV shows and movies,” and “feelings I had.” Those who had read the sad article clung more tenaciously to the past than did those from the other groups—particularly to thoughts of people they were close to: their family, someone they loved, their friends.

Feelings of abandonment can also trigger nostalgia. In a later experiment, the Wildschut team asked the test subjects to fill out a questionnaire and told them it had been designed to assess how lonely they were. The researchers then gave the participants bogus feedback about their responses. Half of the volunteers were told that their answers reflected a sense of abandonment; the other half were told the opposite. Manipulated this way, both groups filled out a nostalgia checklist to see how much they missed 18 elements of their past, such as family, schools and childhood toys.

The results were almost identical to the findings of the previous study. The test subjects who were convinced they felt lonely showed the same yearning for past relationships as did the people who had read the sad article.

These studies yield a consistent picture: people tend to become nostalgic when they feel low-spirited or lonely. But why should this be the case? Does sadness lead people to dwell unproductively on the contrast between their present situation and earlier, happier times? Or do people use nostalgia as a kind of mood enhancer? We decided to find out.

Connecting to Others In 2006 the Southampton team conducted an experiment focusing on how nostalgia affects psychological well-being. Wildschut and his colleagues first asked the test subjects to recall circumstances that were particularly tinged with nostalgia. Then, as a measure of how these reveries affected their disposition, participants reported their current emotions, specifically the degree to which they were feeling “loved,” “protected,” “significant,” “high self-esteem,” “happy,” “content,” “sad” and “blue.” The most nostalgic of the subjects showed high scores in the three measures of happiness, social integration and self-esteem. In other words, nostalgic thinking—which we had earlier found was often triggered by sadness and feelings of disconnection—breeds happier moods.

Our co-workers suspected that one factor in particular accounted for the positive effect of nostalgia on mood: the feeling of social integration. We set out to test whether nostalgia makes people feel a sense of belonging. In our laboratory, we asked participants to evaluate their social competence in three areas: their adeptness in building relationships; their openness with other people about their feelings; and their ability to give a friend emotional support. The participants most likely to engage in nostalgic thinking did better in all three measures of social skills than those in the control group.

This social-glue effect appears to be a universal phenomenon and not simply an artifact of how nostalgia plays out in Western culture. For a 2008 study the Southampton team collaborated with researchers at Sun Yat-sen University in Guangzhou, China. The experimental setup was similar to the earlier study in Southampton, except now with Chinese undergraduates as the test subjects. The researchers asked some of the students to indulge in nostalgic reverie and others to conjure an ordinary memory. The participants then assessed how much support they thought they could count on from friends and family if times grew hard. Once again the results showed that the simple act of recalling a nostalgic memory was enough to make people more certain of the support of their friends. Yearning for the past seems to increase our sense of social support, independent of cultural background.

Happy Endings “To be able to look back on one’s past life with satisfaction is to live twice,” wrote first-century Roman poet Marcus Valerius Martial. And indeed, not only can nostalgia help people recover from sadness and isolation, but golden memories can inoculate against future bad moods. In a 2008 study psychologist Clay Routledge of North Dakota State University and the Southampton team confronted volunteers with the thought of their own death to see if nostalgia could allay this archetypal fear.

In a three-part experiment, the researchers asked half the volunteers to write a short essay about a particular circumstance that made them feel nostalgic. The other participants wrote about a commonplace event from their past. Next, participants were shuffled into two new groups. The first group was asked to answer two questions in writing: “What emotion triggers the thought of your own death?” and “What, in your opinion, occurs in your body when you die, and what happens after you have died?” The second group was asked to write about failing an important test in the past.

Finally, participants were asked to work on a task that tests the extent to which the psyche is unconsciously preoccupied with the question of death. They had to take 28 word fragments (such as “coff”) and suggest a complete word that incorporated the fragment. Six of these fragments could be either part of a word that has something to do with dying (“coffin”) or part of a more neutral term (“coffee”).

Participants who had earlier been pondering their own deaths were more apt to select morbid words. This tendency, though, was not evident among the nostalgics. Those who at the start of the study had reflected on beautiful memories completed the word fragments in a manner that was similar to the participants who in the second part of the experiment had looked back on their flunked exam.

As effective as nostalgia appears to be as a natural mood enhancer, for one large group the benefit can be more elusive: people with depression. A 2007 investigation led by psychologist Jutta Joormann of the University of Miami showed that in contrast to healthy people, patients who suffer from severe depression do not become happier when they think about happy moments from their school days. In fact, exactly the opposite occurs.

The reason appears to be that depressed people do not easily identify with the happier self of their past. A 2008 study led by one of us (Gebauer) at Cardiff University in Wales found that chronically sad people perceive very little similarity between the positive “I” of their memory and their negative self-perception in the present. Instead they believe that this positive “I” is located in a remote past and conclude, “In comparison to the person I was back then, I’m an absolute loser today.” So depressed people can feel even worse after recalling a happy memory.

But not all happy thoughts are equal. Indeed, nostalgia has characteristics that make it different from other positive memories, and these distinctions point to ways in which nostalgia could help depressives. According to the studies by Wildschut and his colleagues, nostalgic recollections are more multifaceted, complex and vivid than mere positive memories. The redemption sequence they often contain could potentially hearten chronically unhappy people; after all, if something turned out well in the past, it could happen that way again.

We are preparing a study to test whether this is the case. We intend to ask both depressed and healthy people to summon three images from the past: an image of themselves as they were five years ago, cast solely in terms of their positive attributes; an image from the same time that casts them solely in terms of their negative attributes; and a purely nostalgic episode, involving a sense of yearning for the past and a mastery or redemption sequence. We expect that only the nostalgic episode will help improve the self-image of people who are depressed, whereas the other two kinds of memories, including the positive one, may worsen it.

For most of us, it seems, nostalgia not only fosters a sense of well-being but, like armor shielding the mind from dark thoughts, protects against psychological onslaughts in the future. Our research shows that nostalgic memories are especially detailed and vivid, in part because we tend to nurture them more assiduously than other memories. Indeed, the more we see how nostalgia provides balm for the wounded psyche, the farther the view of nostalgia as a pathological weakness recedes into the distant, and in this case less rosy, past.