Jerry Mosemak for Al Jazeera America

More than six decades later, Timothy Friedman easily recalls the jostling on the bus that took him across the frozen Volga River in southwest Russia to the orphanage. He was 14 years old when he was sent 530 miles away from Moscow to live in Engels, a small town named after the co-founder of communism. “It was February 1953. There was no bridge, but the Volga freezes over in the winter and vehicles drive on it. A river freezes in a peculiar way,” explained the 75-year-old retired engineer on a recent afternoon at his home near Chatham, New Jersey. “It first freezes near the shore, where the current is slower, then the water breaks the ice and it refreezes in ice-drifts. I still remember how hard the bus rocked. It was the first time I was away from Moscow on my own. A Jewish boy arriving in a small town — I thought, How will they treat me? I can recall the fear today.” Yet some memories make him smile. “There was a boy living near the orphanage with whom I walked to school a few kilometers away. The roads were unpaved. In spring and fall, there were puddles everywhere. The boy carried me piggyback over the puddles. His parents gave him money to treat me to ice cream. What did they care about me, the child of people who were declared enemies of the state and arrested by the Soviet government? But they did. I still remember the taste of the vanilla ice cream, the feeling of being cared for.” After reaching adulthood in the Soviet Union, Friedman immigrated to the United States, where he has lived for the past 35 years. His recollections of his youth are troubled because “the Soviet government ruined too many lives to allow me to remember the past fondly,” he explains. Yet these memories won’t let themselves be forgotten. They may not qualify as trauma, but they surface easily and have an immediacy unmatched by recollections of other, more recent events.

Our memories are the things that make us who we are. They give us a sense of ourselves and inform our behavior. Joseph LeDoux professor of neuroscience

According to Clay Routledge, associate professor of psychology at North Dakota State University, who studies how people bring meaning to their lives through memory, “Nostalgia can be seen as part of the bigger story of how emotions get stored in our memories, neither all positive or negative but as complex, bittersweet feelings.” They stay with us because of the way that the memories were formed, more intensely than other impressions. What makes it nostalgia, he says, is the strong grasp that a memory has on the psyche and how it keeps affecting us. “Our memories are the things that make us who we are,” says Joseph LeDoux, professor of neuroscience at New York University and author of numerous popular books that explore emotional memory. “They give us a sense of ourselves and inform our behavior.”

Storage of intense memories

The term “nostalgia” was coined in the late 17th century by a Swiss physician named Johannes Hofer. He used the roots of two Greek words, “nostos” and “algos” — meaning “suffering” and “origins” — to describe what he thought was a neurological disorder affecting Swiss mercenaries. Although the clinical definition of nostalgia has evolved — it is now considered a psychological condition, and similar to melancholy — scientists agree it does have some neurological underpinnings. LeDoux suggests that although little is known about the neuroscience of nostalgia, it probably has something to do with how memory and emotions are stored in the brain. Short-term memories contain information such as the location of car keys or a clever twitter handle and are stored in the frontal lobe. But long-term memories — such as a friend’s name or how to ride a bike — are moved via neurotransmitters (through a process called “consolidation” that often happens during sleep) to the hippocampus, a part of the brain located deeper in the cranial cavity. Neuroscientists have traced memory to particular brain circuitry, showing how a stable long-term memory is formed through connections between nerve cells. But when a memory is stored at a time of emotional arousal, the imprint is more powerful, possibly due to the neurotransmitters — comparable to hormones in the endocrine system — that the brain secretes in that moment. LeDoux thinks that the process of forming the mental imprint of an event may be closely linked to what is known as “flashbulb memory.” This ultra-clear memory was first identified in 1977 by Roger Brown, professor at Harvard University, and his graduate student James Kulik, currently professor emeritus at the University of California, San Diego. In a telephone interview, Kulik says that at the time, people didn’t think of memory and emotions as closely linked. “Memory research involved primarily memory for words, syllables and other nonemotional stimuli that wasn’t personally meaningful. Roger and I were interested in how intensely personal memories are stored, so to have a common reference point for respondents, we focused on personal memories for public events.” Asking individuals to recall the assassination of John F. Kennedy, they discovered that these memories captured the event with such clarity and vividness that they thought it triggered a unique mechanism in the brain similar to taking a picture, hence the “flashbulb.” Kulik notes that in bringing the study of emotion and memory together, they helped launch the study of autobiographical memory and, more generally, the explosion of research on emotion, which continues to this day. In 2007, NYU psychologist Elizabeth Phelps identified the brain circuitry involved in the creation of flashbulb memories. Her team took scans of people’s brains as they recalled the events of September 11, 2001, and saw that the amygdala, the brain’s emotional center, was lit up. Her work uncovered that the closer one was to the event, the stronger the recollection and the easier it was to retrieve. Although the idea that the brain takes a photograph has been debunked, neuroscience is exploring how emotions drive memories and give them an almost cinematic quality.

I only remember crying once, when they first took me and my brother down to the children’s distribution center in the middle of the night. Timothy Friedman

Friedman agrees that many of his memories are so strong they are hard to forget even if he wanted to. With the same vividness with which he recalled his trip to Engels, he can conjure the memory of the night they took away his mother. It was January 17, 1951. The KGB officers showed up in the middle of the night, as the family slept in the single room assigned to them in their communal apartment. “I woke up, the light was on. Two men in black suits were there, standing and waiting. I understood that they were there to arrest my mother. She was in her nightclothes and asked them to step out while she dressed. They said, ‘No, we’ll wait here.’” He recalls that there was a quick hug. And then his mother was gone. Although today the memories are strongly imprinted, Friedman says he felt no emotion about the events as they transpired. “I only remember crying once, when they first took me and my brother down to the children’s distribution center in the middle of the night. But afterwards, the emotions didn’t get to me. I grew up like a weed, doing what I needed to do.” he added. Friedman is careful not to let his childhood sound too positive and come off as an endorsement of life in the Soviet Union. But there were “many wonderful memories from childhood before my parents’ arrest,” he says, “eating ice cream, picking mushrooms and berries in the forest.” As a result the memories are strong and complicated and have stayed with him, driving his actions as an adult.

Memories give meaning