Eleanor Maccoby, the Barbara Kimball Browning Professor of Psychology, Emerita, at Stanford, recognized for scholarly contributions to gender studies and child and family psychology, died Dec. 11 at age 101 of pneumonia in Palo Alto.

Maccoby was the first woman to serve as chair of the Stanford Department of Psychology, a position she held from 1973 to 1976. At Stanford, Maccoby was associated with the Center for the Study of Families, Children and Youth. Through that work, she became known for research on social and intellectual development in children. She made key contributions to understanding differences in development between girls and boys, infants’ emotional attachments and how divorce and child custody affect children.

“Eleanor was one of the very few tenured women at Stanford in the 1970s, and she was a generous role model for new women faculty,” said Myra Strober, professor emerita at Stanford Graduate School of Education. “She was active in the formation of the Center for Research on Women, which is now the Clayman Institute, and her pathbreaking book with Carol Jacklin on sex differences was exciting and one of the first books in the field of gender studies. She wrote her memoir just before her 100th birthday, continuing to inspire us all.”

Maccoby earned her master’s degree and doctorate in experimental psychology at the University of Michigan. She did the work for her PhD with psychologist B.F. Skinner at Harvard University, where she later taught in the Department of Social Relations and did research from 1950 to 1957. At Harvard, Maccoby participated in large-scale studies investigating whether certain parental practices were related to children’s personality characteristics. The study resulted in the influential book Patterns of Child Rearing in 1957.

Maccoby was born May 15, 1917, in Tacoma, Washington, the daughter of Eugene and Viva Emmons. She attended Reed College for two years, transferring to the University of Washington, where she earned her BA with Phi Beta Kappa honors. She married fellow student Nathan Maccoby in 1938. He died in 1992.

In 1958, the two were offered positions at Stanford University, Nathan in the Department of Communication and Eleanor in the Department of Psychology, teaching child psychology. For a time, Maccoby worked part time to raise their three children and often pursued her academic research late into the evening to preserve family time. In an interview on her 99th birthday, Maccoby remembered that she was Stanford’s first half-time tenured professor. Colleagues remembered her as a tough but popular teacher.

At Stanford, Maccoby’s research turned to the psychology of sex differences. Working with Stanford psychologist Carol Jacklin, she focused on studies involving inequality between men and women, leading to research involving differences in boys and girls.

The author or co-author of 11 books, Maccoby is best known for the 1974 book The Psychology of Sex Differences , co-authored with Jacklin. For the book, they conducted the first large-scale review of the literature on gender differences in an effort to determine which accepted beliefs were based in fact. They also discussed major theories of how sex differentiation occurs, arguing that, in addition to being influenced by their biology and social environment, children engaged in what they called “self-socialization.” The book cast doubt on then widely held assumptions about innate abilities among girls and boys.

In a 2012 interview with Feministvoices.com, Maccoby remembered, “The upshot of that book and its basic message was that most of what we think about as essential differences in the sexes are myths. They aren’t true.”

Maccoby also co-led what was, at that time, one of the largest studies of the effect of divorce on children, published in 1992 as Dividing the Child: Social and Legal Dilemmas of Custody . Maccoby followed about 1,000 California families who began divorce proceedings in 1984-85 and found that fathers, even four years after divorce, stayed substantially involved with their children even though mothers remained the primary caretakers. That involvement was higher than in national studies conducted during the 1970s and 1980s.

Maccoby later wrote The Two Sexes: Growing Up Apart, Coming Together , in 1998, which explored an intriguing paradox: Despite being separated from one another through much of their childhood, most boys and girls form heterosexual unions as adults. To better understand the paradox, Maccoby explored the ways that gender identity helps shape our lives in families, schools, relationships and the workplace.

Dividing the Child was awarded the William J. Goode Award by the American Sociological Association for the most outstanding book on family scholarship. In addition to that award, Maccoby was elected to the National Academy of Sciences in 1993 and won the G. Stanley Hall Award from the American Psychological Association in 1982 and the American Psychology Foundation’s Lifetime Achievement Award in 1996. At Stanford, she was honored with the Walter J. Gores Award for Excellence in Teaching in 1981. In her honor, the American Psychological Association created the Eleanor Maccoby Book Award in Developmental Psychology. The American Psychological Association has listed her as one of the 100 most eminent psychologist of the 20th century.

Maccoby had a lifelong love of music, which began in her youth when she joined her mother and sisters in a professional group with its own radio program. She sang in various choral groups as an adult and, at her 100th birthday, belted out a jazz song from the 1930s, according to her longtime friend Marion Lewenstein, Stanford professor emerita of communication.

“She was a good friend, reaching out to others to be a service when you needed her,” said Lewenstein.

Maccoby is survived by her three children, Janice Carmichael, Sarah Maccoby Blunt and Mark Maccoby; grandchildren Aaron Carmichael, Seth Carmichael, Rebecca Boudreaux, Laura Washington, Nathan Bellina, Eleanor N. Maccoby and Jessica Maccoby; and nine great-grandchildren.

A celebration of life is being planned at the Vi in Palo Alto, a senior living community where Maccoby resided.