Although many women in psychology have made essential and groundbreaking contributions to the field, female psychologists are often overlooked in textbooks.

According to the book A History of Modern Psychology, the only academic jobs typically open to women at the beginning of the 20th century were at women’s colleges. However, these schools often practiced their form of prejudice by refusing to hire married women. The reasoning was that a woman was incapable of managing both a husband and a teaching career.

Women who were early pioneers in psychology were not allowed to study with men. They were denied degrees or found it challenging to secure academic positions that would have enabled them to conduct research and publish papers. They faced discrimination and various obstacles. Yet, they managed to influence not only psychology but also culture in general.

The following list honors both early pioneers and scientists who are making contributions today.

Anna Freud

"How wonderful it is that nobody needs to wait even a single moment before starting to improve the world."

When hearing the last name Freud, many people have a single person in mind: Austrian doctor Sigmund Freud, the founder of psychoanalysis. But not many know that his youngest daughter created the field of child psychoanalysis.

Even though Sigmund Freud stated that children could not be psychoanalyzed, Anna Freud argued that claim. She suggested that child analysis could follow psychoanalysis's fundamental theories, but should have its own distinct therapy model.

She developed new techniques to help children and pointed out that children's symptoms varied from those displayed by adults. According to Anna Freud, this was a result of children's developmental stages.

Also, her writing on the ego's defense mechanisms is still considered fundamental. Anna Freud’s work is regarded as a significant contribution to both ego psychology and adolescent psychology.

Mary Ainsworth

"My advice to mothers is not to miss an opportunity to show affection to their babies."

Mary Ainsworth was a developmental psychologist who was a lead researcher in the field of attachment theory. Her work demonstrated the importance of healthy childhood attachments, and she pioneered the use of a technique known as the "Strange Situation Test."

The "Strange Situation Test" analyzes the pattern of attachment between a child and a mother or a caregiver. In her research, Ainsworth would have a mother and a child sit in an unfamiliar room. Researchers would then observe the child's reactions to various situations, including a stranger entering the room, being left alone with the stranger, and the mother's return to the room.

Mary Ainsworth identified four attachment areas: secure, anxious-resistant insecure, anxious-avoidant insecure, and disorganized/disoriented. This test is still used in psychiatry. Her findings significantly influenced our understanding of attachment styles and how they contribute to behavior later in life.

Mamie Phipps Clark

"A racist system inevitably destroys and damages human beings; it brutalizes and dehumanizes them, blacks and whites alike."

From a young age, psychologist and activist Mamie Phipps Clark was aware of racial segregation. "I became acutely aware of that in childhood because you had to have a certain kind of protective armor about you. You learned the things not to do to protect yourself," said Mamie Phipps Clark in an interview.

Even as a young child, Mamie Phipps Clark knew that she wanted to help other children. She studied psychology and developed a research methodology that combined the study of child development and racial prejudice.

Mamie Phipps Clark’s social psychology work crossed over into the Civil Rights Movement: Her research and expert testimony became instrumental to ending school segregation across the country in the landmark Brown v. Board of Education case of 1954.

One of the most influential studies that Mamie Phipps Clark conducted is "The Doll Experiment''. The researchers used four dolls, identical except for color, to test children's racial perceptions. Children were asked to identify both the dolls' race and which color doll they prefer. A majority of the children picked the white doll and assigned positive characteristics to it. The researchers concluded that "prejudice, discrimination, and segregation" created a feeling of inferiority among African-American children and damaged their self-esteem.

Mamie's Phipps Clark's research on racial identity and self-esteem also helped pave the way for future research on self-concept among minorities.

Leta Stetter Hollingworth

"Women are as intelligent and capable as men."

Leta Stetter Hollingworth is best known for her contributions to the psychology of women and the education of the gifted, the latter culminating in two books, Gifted Children and Children Above IQ 180.

One of her most important contributions was the research on the psychology of women. At the beginning of the 20th century, the prevailing opinion was that women were both intellectually inferior to men and semi-invalid when menstruating. The belief that menstruation made women incapacitated had a significant impact on women's rights since many employers refused to hire women because they believed they would be incapable of performing their duties for about one week each month.

Leta Stetter Hollingworth challenged these assumptions, and her research showed that women were as intelligent and capable as men were, no matter what time of the month it was. She also tested women and men on various tasks that tested mental abilities and motor skills. The conclusion was that there were no performance differences at any point in a woman's menstrual cycle.

Leta Stetter Hollingworth's work contributed to a revolution of the perception of women and eventually a push for women's rights.

Jennifer Eberhardt

"When people focus on not seeing color, they may also fail to see discrimination."

Jennifer Lynn Eberhardt is a social psychologist who is currently a professor in the Department of Psychology at Stanford University. Her work has revealed how racial imagery and judgments shape actions and outcomes in our criminal justice system, in addition to our neighborhoods, schools, and workplaces.

She has been contributing to investigating the consequences of the psychological association between race and crime. Eberhard also contributed to research on unconscious bias, including demonstrating how racial imagery and judgment affect culture and society within the domain of social justice. A cognitive bias is a systematic pattern of deviation from norm or rationality in judgment. Individuals create their own "subjective reality" from their perception of the input.

The results from her work have contributed to training law enforcement officers and state agencies to better their judgments through implicit bias training. These implicit bias training programs are designed to expose people to their implicit biases, provide tools to adjust automatic thinking patterns, and ultimately eliminate discriminatory behaviors.

Over the decades, Jennifer Lynn Eberhardt and her Stanford team have explored the roots and ramifications of unconscious bias, from the neuron level to that of society. In the experiments, she has shown how social conditions can interact with the workings of our brain to determine our responses to other people, especially in the context of race.

Jennifer Lynn Eberhardt is the author of the book Biased: Uncovering the Hidden Prejudice That Shapes What We See, Think, and Do. She was a recipient of the 2014 MacArthur "Genius Grant" Fellowship, been named one of Foreign Policy's 100 Leading Global Thinkers, and was elected to the National Academy of Sciences and the American Academy of Arts Sciences.

Melanie Klein

"The root of creativity is found in the need to repair the good object destroyed during the depressive phase."

Melanie Klein was a psychoanalyst known for her work in the field of child psychoanalysis. She was an inventor of “play therapy”, a technique that enables children to express themselves through toys. Klein was also a founder of the British object relations school of psychoanalysis and an early theoretician of emotions and their significance in human development.

Play therapy is a technique used to help children express their feelings and experiences in a natural and helpful way. Melaine Klein observed that children often utilize play as one of their primary means of communication. And since young children are not capable of some of the more commonly used Freudian techniques, she began to use play therapy to investigate children's unconscious feelings, anxieties, and experiences.

Klein's play therapy technique is still widely used today. Her emphasis on the role of the mother-child and interpersonal relationships on development also significantly influenced psychology.

What the future holds

At present, less than 30 percent of researchers worldwide are women. According to UNESCO data, only around 30 percent of all female students select STEM-related higher education fields.

“I’m always a female scientist. I’m never just a scientist,” said Caroline Simpson, an astronomer, and professor in the Department of Physics at Florida International University.

Even though women have made revolutionary scientific contributions throughout history, some still experience gender discrimination and lack of recognition in the scientific community. Retaining women in the sciences should probably include changing institutional cultures but also ensuring that women are included, recognized, and heard.