Eleanor Maccoby

Introduction

Eleanor Emmons Maccoby (15 May 1917 – 11 December 2018) was a developmental psychologist who spent six decades asking how much the evidence behind confident claims would actually carry.

She is best known for The Psychology of Sex Differences (1974), written with Carol Nagy Jacklin, which reviewed the entire literature on psychological differences between the sexes claim by claim. The book is routinely described, usually by people who have not read it, as having proved that men and women are the same. It said no such thing. What it found was that a great many accepted differences rested on evidence too sparse, inconsistent, or contradictory to support them — and that a smaller set survived as more consistently observed. That qualification was the finding, not a hedge on it.

The book's most consequential discovery was methodological. Maccoby and Jacklin noticed that studies finding no sex difference were systematically missing from the literature, because they could not get published. They went looking for them and included as many as they could find. The result was probably the first large-scale attempt to correct for publication bias in psychology — two decades before the term existed.

Early Life and Education

Eleanor Emmons was born in Tacoma, Washington. She spent two years at Reed College before transferring to the University of Washington, where she took her bachelor's degree with Phi Beta Kappa honours. In 1938 she married Nathan Maccoby, also a student and later a psychologist in his own right.

She took her master's degree in 1949 and her doctorate in 1950, both in experimental psychology at the University of Michigan. The research for the doctorate was done at Harvard with B.F. Skinner, which is a useful thing to know about her: the person who went on to challenge the field's confident stories about gender was trained in the most rigorous and least interpretive tradition in American psychology.

She later said she had experienced very little sexism early in her career. That changed during the Vietnam War protests, when student activists published faculty salaries and she discovered she was among the lowest paid on the Stanford campus. "Feminist concerns then began to resurface in a hurry," she said. The shift was sharpened by working with her postdoctoral fellow Carol Jacklin, who she recalled was "much more intensely feminist than I was" at the time.

Academic and Professional Career

Maccoby taught at Harvard's Department of Social Relations from 1950 to 1957, working on large-scale studies of whether specific parental practices were associated with specific personality characteristics in children. That work produced Patterns of Child Rearing (1957), which became influential and which she would later help overturn.

In 1958 she and Nathan were both offered positions at Stanford. Anti-nepotism rules meant they had to be placed in different departments — he in Communication, she in Psychology, where she was hired to teach child psychology. The appointment was part-time, which suited her at the time because she had three children, and she recalled being Stanford's first half-time tenured professor. She did much of her research late in the evening in order to protect family time.

She became a full professor in 1964 and, from 1973 to 1976, was the first woman to chair Stanford's psychology department.

She served as president of the Western Psychological Association, of the APA's Division 7 (Developmental Psychology) from 1971 to 1972, and of the Society for Research in Child Development from 1981 to 1983. She received the G. Stanley Hall Award in 1982 and the American Psychological Foundation's Lifetime Achievement Award in 1996. APA Division 7 now awards the Maccoby Award in her name.

She remained intellectually active into her nineties, completing a memoir shortly before her hundredth birthday. She died of pneumonia on 11 December 2018, aged 101.

Major Contributions to Psychology

The Psychology of Sex Differences

The project began in exasperation. Reading the clinical literature on sex differences, Maccoby encountered the claim that males are active and females are passive. "'Passive!' What in the world could anybody mean?"

What she and Jacklin found as they reviewed the literature was worse than weak evidence. They knew colleagues who had looked for sex differences, found none, and either never published or had the analysis dropped from the final manuscript. She gave a specific example: a widely cited claim that women betrayed their partners more often in prisoner's dilemma games, against which there existed nearly thirty replications finding no difference, none of them published.

So they did something unusual for 1974 — they went and found the unpublished null results and put them in. The resulting book ran to over six hundred pages with an annotated bibliography of well over a thousand studies, and it assessed each claimed difference against the whole of the available evidence rather than the published part of it.

The verdicts were mixed, and that was the point. Differences in sociability, suggestibility, self-esteem, analytic ability, and achievement motivation did not hold up. Her summary: "most of what we think about as essential differences in the sexes are myths. They aren't true."

But other differences did hold up more consistently, and the book said so. The reputation the book acquired — as having proved that the sexes are the same — is a distortion that has been equally useful to people who wanted to celebrate it and people who wanted to dismiss it.

Socialization and bidirectional influence

Patterns of Child Rearing, which she co-authored in 1957, belongs to the tradition that asked how parental practices shape children. Her later work was part of the movement that dismantled that assumption's one-directionality: children affect parents at least as much as parents affect children, and the correlation between a parenting practice and a child outcome does not establish which caused which.

Her 1983 chapter with John Martin, "Socialization in the Context of the Family," reframed the family as a system of mutual influence and set the terms for the following decades of socialization research. It also consolidated the parenting framework organised around responsiveness and demandingness, including the fourth category — neglectful — that she and Martin added to the typology then in use.

Across her later work, culminating in The Two Sexes (1998), Maccoby argued that gender operates as a social category rather than only as an individual trait. Her research on childhood peer groups showed that children segregate by sex spontaneously and early, and that gendered behaviour is activated by the company a child is in rather than being a fixed property carried around — a child who behaves one way in a same-sex group behaves differently in a mixed one.

Divorce and custody

In the 1980s and 1990s she co-led one of the largest studies then conducted on the effects of divorce on children, following families over years and examining outcomes under different custody arrangements. Dividing the Child (1992), with Robert Mnookin, examined the social and legal dilemmas of custody and fed directly into family law reform in California and elsewhere.

Major Publications

Patterns of Child Rearing (1957, with Robert Sears and Harry Levin)
The Development of Sex Differences (ed., 1966)
The Psychology of Sex Differences (1974, with Carol Nagy Jacklin)
Social Development: Psychological Growth and the Parent–Child Relationship (1980)
"Socialization in the Context of the Family" (1983, with John Martin)
Dividing the Child: Social and Legal Dilemmas of Custody (1992, with Robert Mnookin)
Adolescents After Divorce (1996, with Christy Buchanan and Sanford Dornbusch)
The Two Sexes: Growing Up Apart, Coming Together (1998)

Impact and Legacy

Maccoby's review changed how the field handles claims about group differences generally, not just sex differences. The method — assemble everything, including what was not published, and ask whether the evidence bears the weight of the claim — is now standard, and her discovery that the published literature systematically overstates differences is the canonical example of publication bias in psychology. The book has been cited more than five thousand times.

Her work on divorce reshaped custody practice, and her reframing of parent–child influence as bidirectional is now assumed rather than argued.

Criticism. Her method was the best available in 1974 and has been superseded. Counting studies that do and do not find a difference — vote-counting — was replaced by meta-analysis, which aggregates effect sizes rather than tallying significance, and the difference matters: a literature can contain many null results and still contain a real effect that each individual study was too small to detect.

The framework is also binary by construction. Comparing males against females, and treating each as a homogeneous category, leaves no room for the variation within each sex or for how gender intersects with other social categories — an absence that is particularly conspicuous in work that became foundational for gender studies.

Her peer-culture account of gender development has been criticised for being better at explaining group patterns than individual trajectories. It describes why boys and girls segregate and why behaviour shifts with company, but it is thinner on why two children in the same environment diverge.

The parenting typology she helped consolidate is now used far beyond what the evidence supports. The four categories are a useful teaching device, and their application to predict individual outcomes in individual families considerably exceeds their demonstrated validity.

There is also a question about attribution. Much of her best-known work was done with collaborators — Jacklin, Martin, Mnookin, Sears — and her reputation has grown in part by absorbing theirs. Carol Jacklin, in particular, was a junior collaborator on the book that made both their names, and the subsequent distribution of credit has not been even.

What is hardest to dismiss. She trained under Skinner, in the tradition most hostile to unverifiable interpretation, and spent her career applying that discipline to claims that everyone, including her, had reasons to want to be true. Her own summary of the disposition is the best thing in the record: "You have to care about how experiments come out and let yourself be guided by their results."

Learn More

B.F. Skinner — with whom she did her doctoral research, and whose rigour she applied elsewhere
Leta Hollingworth — who attacked the male-variability hypothesis a generation earlier with the same method
Anne Anastasi — who worked the same territory from inside psychometrics
Developmental Psychology — the field she spent six decades shaping

References

Maccoby, E. E., & Jacklin, C. N. (1974). The Psychology of Sex Differences. Stanford University Press.