Anni Bergman, an Austrian-born psychoanalyst who worked with autistic children and contributed to a landmark study of early childhood development, died on Oct. 2 at home in Manhattan. She was 102.

Her son Tobi confirmed the death.

Dr. Bergman was a 40-year-old mother and music teacher when she was hired by Margaret Mahler, a child psychiatrist and psychoanalyst, to help with a study of mothers and babies at a therapeutic nursery in the West Village. (A friend had turned down the job — Dr. Mahler was known to be difficult — and Dr. Bergman, who was interested in the field, applied.)

For more than a decade, starting in 1959, Dr. Bergman and others watched as the babies found their legs, as it were — or didn’t. They observed how many ventured out on their own, and the various ways their mothers supported, or inhibited, such explorations.

“It’s that moving away and coming back that’s very important,” Dr. Bergman told an interviewer in 2012. “We learned that separation isn’t always difficult. It isn’t always the baby that is left. Sometimes it is the baby that is leaving.”

The study was groundbreaking at the time. Freudian theory, which still dominated therapeutic practices, had long dictated that the proper setting for learning about what Dr. Bergman called the internal world was in the analyst’s office, and that in any case babies couldn’t tell us much about that world until they began to talk.

“Pre-Oedipal development was seen as a prelude to the main Oedipal drama,” she wrote in 2000 in her introduction to a reissue of “The Psychological Birth of the Human Infant: Symbiosis and Individuation,” written with Dr. Mahler and Fred Pine, another noted psychoanalyst, and first published in 1975. The book detailed the group’s work, which came to be known as separation-individuation theory.

The group’s other big idea was to use observation and not theory to organize such a study — observation without judgment, as Dr. Bergman liked to say. And Dr. Bergman turned out to be an extraordinary observer, able to interpret a baby’s behavior with uncanny skill.

This made her especially adroit at understanding autistic children, which became her calling. In a separate study, she and her colleagues worked with mothers and their autistic or psychotic children. Tripartite treatment — working together with parents and their children — was a rare practice at the time.

“We felt like explorers in an obscure realm of preverbal and presymbolic development,” Dr. Bergman wrote. “A spirit of excitement prevailed.”

Anna Emilie Rink was born on Jan. 10, 1919, in Vienna. Her father, Ernst, owned a factory. Her mother, Marta (Haas) Rink, a homemaker, died of influenza when Anni was 10; two sisters also died from the disease. Her father died when she 17. The family was well off, and Anni was cared for by a household staff that included a chauffeur, a cook and a nanny.

She left Vienna in 1939, traveling by ship from Italy to Los Angeles.

“When she would tell of her escape from the Nazis,” her son Tobi said, “people would say how horrible and frightening it must have been to be torn from home and thrown as a young woman all alone into an unknown world. She always told people that on the contrary, she was leaving a sheltered and repressive world behind and embarking on a great adventure. She was going to America!”

In Los Angeles, Anni found work as an au pair and assistant to Christine Olden, a psychoanalyst who, like Anni, was from Austria, and attended the University of California, graduating with a bachelor’s degree in music. (She would later earn a master’s degree at the Bank Street College of Education.) Among the group of European expatriates who made up Dr. Olden’s circle was Peter Bergman, a Polish-born activist, publisher and writer who had worked to help people escape the Nazis. Anni and Peter fell in love and married soon after moving to New York in 1943.

Anni worked as a music teacher at a progressive school in the East Village and co-wrote a children’s primer on playing the recorder. Peter opened a publishing company, the Polyglot Press, in a four-story brick townhouse in Chelsea. When he bought the building, the family moved in.

Dr. Bergman’s office was on the top floor, and she decorated it with zest and flair, with flower-patterned wallpaper, brightly colored textiles and shelves overflowing with books and other collections.

With its riot of colors and objects, being in her office “was like stepping into a magical world,” said Sebastian Zimmerman, a psychiatrist and photographer who included Dr. Bergman in “Fifty Shrinks,” his 2014 book of portraiture showing therapists in, as he put it, their natural habitats. Dr. Bergman explained that she had designed her office to be “a secluded world where the children have the complete freedom to express themselves and explore.”

In 1978, Dr. Bergman co-founded a therapeutic nursery for autistic and psychotic children at the City College of New York. She earned her Ph.D. in clinical psychology from the City University in 1983. She was a faculty member and supervisor there and at New York University and the Contemporary Freudian Society.

In the late 1990s, with Rita Reiswig, a psychoanalyst who also focused on mothers and babies, she founded a program for parent-infant studies that in 2006 was renamed the Anni Bergman Parent-Infant Training Program.

“Anni could put into words the experience of a child in a way that was extraordinary,” said Sally Moskowitz, the program’s co-director. “She could reach any child and make a connection.”

Dr. Bergman was among a group of therapists directed by Beatrice Beebe, a researcher of mother-infant communication and a clinical professor of psychology at Columbia University Medical Center, who worked with pregnant mothers widowed by the Sept. 11 terror attacks. In 2005, she also began collaborating with Miriam Steele, director of the Center for Attachment Research at the New School, and Inga Blom, then a graduate student, on a follow-up study of the children who had been part of Dr. Mahler’s study and were then in their mid-40s.

“You could see the aspects they carried forward,” Dr. Steele said, noting that some of the anxious babies had developed into grown-ups “avoidant in attachment context,” while others, thanks to Dr. Bergman’s early interventions, were secure adults.

Colleagues described Dr. Bergman as fearless and said they were awed by her athleticism, which was unchecked by her advanced age. Until she was 92, she rode a bicycle through the chaotic Manhattan streets. She swam weekly until she was 97.

Late in life, she became a muse to another photographer-therapist, Ann Steiner, who began taking photographs of Dr. Bergman in 2014, when she was 96, and continued until she was past her centennial. For years, Dr. Steiner photographed Dr. Bergman in her Chelsea townhouse and throughout the city, capturing her in a series of animated portraits.

In addition to her son Tobi, Dr. Bergman is survived by another son, Kostia; a stepdaughter, Vera Buettner; five grandchildren; 10 great-grandchildren, and six great-great-grandchildren. Mr. Bergman died in 1995.

One of Dr. Bergman’s innovations in the treatment of autistic children was to add a helper to the mix: a therapeutic companion, as she described it, who could help the child navigate his or her world. One oft-told example of how this relationship worked was that of a child who wanted to take down all the items from the shelves of a grocery store.

Dr. Bergman persuaded the shop’s manager to allow the behavior, explaining that the companion would put everything back. She knew that behind the child’s impulse was a need to establish her own sort of order on the world.