History of psychology & its thinkers

In ancient Egypt, healing was closely tied to religion. Priests often served as healers, and illness was frequently explained by curses, spirits or the anger of gods. Alongside this, Egyptian physicians built up practical knowledge.

The Ebers Papyrus, from around 1550 BCE, is one of the oldest medical texts known. It collects hundreds of remedies and spells. Egyptian care also used gentle approaches such as massage, baths and changes in diet.

Hippocrates and the doctors who followed him in ancient Greece looked for natural explanations for illness, based on careful observation, rather than only blaming the gods. He is often called the father of Western medical science.

Their theory said the body holds four fluids, or “humours”: blood, phlegm, yellow bile and black bile. Health meant balance; illness meant imbalance. Too much black bile was linked with melancholia, an old word for deep, lasting sadness. Treatments aimed to restore balance through diet, bloodletting, purging and other methods of the time.

The Roman doctor Galen later expanded these ideas. Humoural theory then guided medical care in Europe and the Muslim world for well over a thousand years.

Ayurveda, meaning “science of life”, is India’s traditional system of healing, rooted in very old Vedic traditions. It sees health as balance and harmony between body, mind and spirit, and uses diet, daily routines, yoga, meditation and spiritual guidance.

A classic Ayurvedic text, the Charaka Samhita, describes ways to care for the mind. A 2025 review found it encourages spiritual awareness, wisdom, fortitude (inner strength) and meditation, and a balanced, ethical life. The reviewers noted how these ideas echo today’s focus on strengths and flourishing.

The Yellow Emperor’s Inner Canon (Huangdi Neijing) is a founding text of traditional Chinese healing. Its compilation was probably completed during the Han dynasty, roughly 2,000 years ago. It saw health as harmony between the person and nature, and as a smooth flow of life energy (qi).

The Inner Canon taught that too much of any emotion, even joy, could harm the body. Later Chinese physicians recorded an “emotion-overcoming” approach: helping a person move out of a stuck feeling by creating an experience that sparked a different, strong feeling. For example, a classic saying is “joy overcomes worry”.

Hunayn ibn Ishaq al-‘Ibadi was perhaps one of the first physicians in the Muslim world to extend the ideas of the Greek doctor Galen. His work influenced the physicians who came after him.

His “six non-naturals”: things that shape health

• Air
• Emptying the body (the cleansing methods of the time)
• Food and drink, taken regularly
• Waking and sleep
• Whatever affects us emotionally, such as worry, fear, anger and joy
• Work (including exercise) and rest

Al-Balkhi was a scholar who wrote Sustenance of the Body and Soul (Masalih al-Abdan wa al-Anfus). In it, he discussed illnesses of the body and of the mind (the “soul”, or nafs) and argued that each can cause problems in the other. Researchers describe him as one of the first to write in depth about this two-way link.

Ideas from his book that researchers highlight

• He described different kinds of sadness: everyday sadness, sadness that comes from within a person, and sadness caused by outside events. Researchers compare this with how depression is understood today.
• He wrote about fear and anxiety, anger, sadness, and obsessions (repeated, unwanted thoughts) as separate problems.
• He offered coping methods for each one, including working with thoughts, keeping active and getting support from others.
• He noted the importance of clean air, pure water, good housing, food and exercise for wellbeing.

A 2025 study in a psychiatry journal found that al-Balkhi noticed thinking patterns like catastrophic thinking (expecting the worst), an idea now central to cognitive behavioural therapy (CBT). Scholars say he described ideas similar to today’s cognitive therapy. They also caution against claiming he “invented” CBT, since his world and words were very different from ours.

Al-Razi was a Persian physician who studied and worked in Baghdad, the great centre of learning in his time, and later led the hospital in his home city of Ray, near today’s Tehran.

He wrote al-Tibb al-Ruhani, a book on healing the soul, about mental health and healthy habits of mind and behaviour. He also kept records of patients from diagnosis to outcome, an early form of case notes. A 2020 review notes he described problems like low mood and delusions, and used talking approaches for problems such as obsessions.

A 2024 medical history review credits him with setting up one of the first psychiatric wards, in Baghdad, giving people with mental illness a place in the hospital for medical care.

Melancholia, a deep and lasting sadness, was perhaps the most discussed mental health condition of the era. Physician Ishaq ibn ‘Imran described it as sadness linked to excess black bile and a loss of ‘aql (reason).

Writers of the time linked melancholia to feelings of powerlessness, dejection, isolation and sadness (al-huzn). Many of these words still describe how low mood feels today.

Ibn Sina was a physician and philosopher. His great work, The Canon (al-Qanun fi al-Tibb), is a five-book encyclopaedia of medical knowledge. It was translated into Latin in the Middle Ages and stayed a key medical authority in Europe and the Muslim world until about the 1600s.

In The Canon, he linked different body states with mental troubles such as anxiety, obsessions and melancholia, following the humoural ideas of the time. In other writing, he explored how reason and philosophy could help a troubled mind.

Al-Ghazali was a renowned philosopher and theologian. He described the inner self as made up of the heart (qalb), spirit (ruh), intellect (‘aql) and self (nafs). He argued that balance and connection between them is essential, and that losing this balance leads to trouble.

Islamic writing on the nafs describes stages from a self pulled by impulses, to a self that reflects and corrects itself, to a self at peace. Some modern writers have compared these stages with Freud’s id, ego and superego, but other scholars question whether such a like-for-like match really fits.

Bimaristans were hospitals in the medieval Muslim world, often funded by charitable endowments. They were known for caring for the poor and marginalised, often at little or no cost. Doctors of different faiths, including Christian and Jewish physicians, worked side by side.

Famous examples

• The ‘Adudi hospital in Baghdad (982), with around two dozen doctors, a library and lecture halls
• The Nuri hospital in Damascus (1146)
• The Mansuri hospital in Cairo (1284), with separate wards for men and women, open to everyone whatever their wealth

Historians believe wards for people with mental illness likely existed from the earliest hospitals. Care for mental illness included music, pleasant scents and talking, alongside the medical treatments of the time. Patient records were used to train new doctors, a link between hospitals and teaching that Europe adopted much later.

Bimaristans were seen as places of healing (bayt al-shifa). Courtyards with fountains and plants were designed to feel calm, and patients were regularly fed and checked on. Restraints were sometimes used too; some historians argue this was meant as treatment rather than punishment. It was not a perfect system, but it was remarkably caring for its time.

By the 1700s, asylums were built across Europe to house people with mental illness. Their main aim was to keep people away from society, not to help them recover. Many people were chained and had little contact with caregivers.

French physician Philippe Pinel argued for humane care. In 1795, at La Salpêtrière hospital in Paris, he had patients unchained and spent time talking with them. Many improved, and some were able to leave.

In York, England, the Retreat was founded by and for the Quakers (Society of Friends), with William Tuke and Samuel Tuke among its leading figures. It opened in 1796 with 12 patients.

It became known for more compassionate methods: a calm, home-like setting, respect, meaningful work and daily routine instead of chains and harsh punishment. This approach became known as “moral treatment” and inspired reformers in other countries.

In the 1800s, American reformer Dorothea Dix investigated how poor people with mental illness were treated. She found an underfunded and abusive system and lobbied state lawmakers and Congress for change, which led to new public hospitals.

Sadly, many hospitals later became overcrowded and offered little real treatment, with harsh practices continuing into the 1900s. Reform is never finished.

German scientist Wilhelm Wundt set up the first psychology laboratory at the University of Leipzig in 1879. He studied conscious experience by training people to describe their own thoughts and sensations (introspection).

Introspection turned out to be very subjective; people often disagreed. But the idea of testing the mind with careful methods stuck. Around the same time, William James in the U.S. asked how the mind helps us adapt to life, an approach called functionalism.

Sigmund Freud (1856–1939) proposed that many problems come from the unconscious mind, which he explored through free association and dreams. Psychoanalysis dominated clinical psychology for several decades. Modern versions of his approach have been shown in research to help.

Russian scientist Ivan Pavlov showed that dogs could learn to link a sound with food (classical conditioning). In the early 1900s, American psychologist John B. Watson argued that psychology should study only behaviour we can observe. Later, B. F. Skinner studied how rewards and consequences shape behaviour.

Behaviourism dominated experimental psychology for decades. Its ideas live on in behaviour therapy, exposure therapy and habit-building tools.

Max Wertheimer, Kurt Koffka and Wolfgang Köhler argued that we experience things as whole patterns, not just pieces. They brought these ideas to the U.S. after leaving Nazi Germany. Their work influenced how we study perception and problem-solving.

Humanistic psychology grew in reaction to the gloominess of psychoanalysis and the narrowness of behaviourism. Abraham Maslow described a hierarchy of needs reaching up to self-actualisation. Carl Rogers developed client-centred therapy, built on genuineness, empathy and unconditional positive regard.

By the 1950s, progress in language science, brain science and computing brought fresh interest in the mind. Ulric Neisser published the first cognitive psychology textbook in 1967, and linguist Noam Chomsky was an early influence.

In therapy, Albert Ellis created rational emotive behaviour therapy (REBT) in the 1950s, and Aaron Beck developed cognitive therapy in the 1960s, which grew into CBT. Both showed that changing how we interpret events can change how we feel.

Until the 1960s, psychology was largely run by men, and most research was done on men. Many pioneers pushed to make the field fairer and more accurate.

A few of them

• Margaret Floy Washburn: the first woman to earn a doctorate in psychology (1894).
• Francis Cecil Sumner: the first African American to earn a PhD in psychology in the U.S. (1920).
• Inez Beverly Prosser: the first African American woman to earn a PhD in psychology (1933).
• Mamie Phipps Clark and Kenneth Clark: their research with children was instrumental in the U.S. Supreme Court case that ended school segregation (Brown v. Board of Education).
• George I. Sánchez: challenged intelligence tests that were unfair to Mexican American children because of language and culture.
• Martha Bernal: the first Latina to earn a doctorate in psychology (1962).
• Naomi Weisstein: her 1968 article challenged psychology’s biased views of women.

Austrian neurologist Sigmund Freud proposed that hidden (unconscious) thoughts, memories and wishes shape our feelings and behaviour. He developed psychoanalysis, using free talking and attention to the relationship with the therapist.

Ideas you may know

• The unconscious mind
• Id, ego and superego
• Defence mechanisms like denial and repression (later organised by his daughter Anna Freud)
• Dreams as a window into the mind

Legacy and limits: he was one of the most cited psychologists of the 20th century, and talk therapy owes him a lot. But critics argue many of his ideas lacked scientific evidence, focused too much on sex, and relied on case stories. Modern psychodynamic therapy has kept some ideas and dropped others.

Swiss psychiatrist Carl Jung worked with Freud before founding “analytical psychology”. He introduced ideas like introversion and extraversion, archetypes (shared symbols such as the hero or the wise elder), the shadow (parts of ourselves we hide), and a “collective unconscious”.

Legacy and limits: introversion and extraversion live on in modern personality research. The collective unconscious, however, is strongly disputed by scientists. Jung’s ideas remain popular in art, storytelling and some therapies.

American psychologist B. F. Skinner studied how rewards and consequences shape behaviour, which he called operant conditioning. He showed that new behaviours can be built step by step, by rewarding small moves in the right direction (called “shaping”).

How it shows up today: praise charts for children, building habits with small rewards, and behavioural parts of many therapies. If you reward yourself after a workout, you are using Skinner’s ideas.

American psychologist Abraham Maslow helped found humanistic psychology, which focuses on human potential rather than just problems. He is best known for the hierarchy of needs, proposed in 1943.

Legacy and limits: research supports that his needs matter around the world, but not the strict order. See “Needs & motivation” in the “Psychology basics: big ideas” guide.

American psychologist Carl Rogers developed person-centred therapy in the 1940s. He believed people naturally grow toward their best selves when they feel understood and accepted. The client, not the therapist, is the expert on their own life.

His three core conditions

• Empathy: truly trying to understand the other person’s world.
• Unconditional positive regard: accepting the person, whatever they share.
• Congruence: being genuine, not hiding behind a role.

Legacy: his ideas shaped nearly all modern therapy and are useful for anyone who listens, from parents to friends to teachers.

British psychiatrist John Bowlby challenged the view of his time that babies bond with mothers mainly because they are fed. He argued that the bond itself is a basic need, and that a caregiver acts as a secure base to explore from and a safe haven to return to.

He also described “inner working models”: mental maps of whether others will be there for us and whether we are worthy of care. These maps shape later relationships but can be updated.

American-Canadian psychologist Mary Ainsworth studied mothers and babies in Uganda and the United States. She developed the Strange Situation procedure and the idea that a caregiver’s sensitivity, noticing and responding to a baby’s signals, shapes how secure the baby feels.

Her work identified secure and insecure patterns of attachment, which later researchers extended to adult relationships.

Swiss psychologist Jean Piaget showed that children think differently from adults, not just less. He described four stages of thinking and the processes of assimilation and accommodation.

Legacy and limits: his ideas shaped education worldwide, though later research shows children are often more capable, earlier, than he believed.

German-American psychoanalyst Erik Erikson built on Freud’s ideas but focused more on social relationships and culture. He described eight life stages from infancy to old age.

Legacy: his view that adults keep growing, not just children, was groundbreaking. See “How we grow” in the “Psychology basics: big ideas” guide for all eight stages.

Austrian psychiatrist Viktor Frankl survived Nazi concentration camps, including Auschwitz. He founded logotherapy, built on the belief that the search for meaning is our main human motivation. His book Man’s Search for Meaning blends his camp experiences with his ideas.

Three paths to meaning

• Doing: work, creating, contributing.
• Experiencing: love, beauty, nature, connection.
• The attitude we take toward suffering we cannot avoid.

Frankl did not believe suffering is meaningful in itself. Meaning comes from how we respond to it. His ideas are widely used in grief support and counselling.

Canadian-American psychologist Albert Bandura is famous for the Bobo doll studies in the early 1960s. Children who watched an adult hit an inflatable doll were more likely to act aggressively themselves. It showed we learn by watching, not only through rewards and punishments.

In 1977 he introduced self-efficacy: your belief that you can do what is needed to reach a goal. People with high self-efficacy tend to set bigger goals and recover from setbacks more readily.

American psychologist Albert Ellis created rational emotive behavior therapy (REBT) in the 1950s. At first his ideas were widely rejected, but they became a foundation for today’s thinking-based therapies.

His key insight: our beliefs about events, especially rigid “musts”, drive much of our distress. See “Thoughts & feelings” in the “Psychology basics: big ideas” guide.

American psychiatrist Aaron Beck began by studying depression through a psychoanalytic lens. When the evidence didn’t support those ideas, he developed cognitive therapy, which became cognitive behavioral therapy (CBT). He also created widely used questionnaires about mood and hopelessness.

Legacy: CBT is one of the most researched talking therapies in the world. See “Thoughts & feelings” in the “Psychology basics: big ideas” guide for how it works.

American psychologist Martin Seligman co-discovered learned helplessness in the 1960s and later updated the theory with brain research. He then studied how people can learn more hopeful ways of explaining setbacks.

In 2000 he helped launch positive psychology, the study of strengths, wellbeing and meaning. See “Thoughts & feelings” and “Wellbeing & resilience” in the “Psychology basics: big ideas” guide.

American psychologist Marsha Linehan developed DBT starting in the 1970s. “Dialectical” means holding two opposite ideas at once: accepting yourself as you are and working to change.

DBT’s four skill areas

• Mindfulness: being present.
• Distress tolerance: getting through hard moments without making things worse.
• Emotion regulation: understanding and managing feelings.
• Interpersonal effectiveness: asking for what you need and setting boundaries.

Legacy: DBT skills are now taught in schools, clinics and groups around the world, well beyond the people it was first designed for.

American psychologist Carol Dweck studied how people’s beliefs about ability affect how they handle challenges and failure. Her work on growth mindset became hugely popular in schools.

Later research found real but modest effects that depend on the setting. See the growth mindset card in the “Psychology basics: big ideas” guide for the honest picture.

Psychologists Amos Tversky and Daniel Kahneman studied how people make judgments when they can’t be sure. In a famous 1974 paper, they described mental shortcuts such as anchoring, availability and representativeness, and the predictable errors they cause.

Their work laid the foundation for behavioural economics and influenced health care, law and public policy. Kahneman received the 2002 Nobel Prize in economic sciences. Tversky had died in 1996, and the prize is not given after death. Kahneman’s 2011 book Thinking, Fast and Slow brought these ideas to a wide audience.

American psychologist Elizabeth Loftus studied how memory can change after an event. In a 1974 study with John Palmer, simply changing one word in a question (“smashed” instead of “hit”) changed how fast people thought cars were going, and even made some remember broken glass that wasn’t there.

Why it matters: eyewitnesses can be honest, confident and still wrong. Mistaken eyewitness identification played a part in about three in four of the first 239 U.S. convictions overturned by DNA evidence.

In 1955, more than 558,000 people with serious mental illness lived in U.S. public psychiatric hospitals. New treatments and a push for community-based care changed this. In 1963, a U.S. law funded community mental health centres, and over the following decades the number of people in hospitals fell sharply.

The idea was good: people should live in their communities with support. But many community centres were underfunded, and housing, food and job support were often missing. Many people who left hospitals ended up homeless or without care.

In 2000, Martin Seligman and Mihaly Csikszentmihalyi called on psychology to study what makes life worth living. See “Wellbeing & resilience” in the “Psychology basics: big ideas” guide.

A trauma-informed service realises how widely trauma affects people and understands paths to recovery. It builds that knowledge into its policies and everyday practice.

Principles SAMHSA describes

• Safety: people and staff feel safe in body and mind
• Peer support: shared experience builds hope and trust
• Trustworthiness and transparency
• Collaboration and mutuality: sharing power
• Empowerment, voice and choice

Peer support specialists use their own experience of mental health struggles to support others. Research links peer support with better quality of life, more engagement with services and fewer hospital stays.

The World Health Organization’s Mental Health Gap Action Programme (mhGAP) aims to scale up care for mental, neurological and substance use conditions, especially in low- and middle-income countries. Its guidelines, first issued in 2009, help everyday health settings, not just specialist clinics, offer care.

This echoes something very old. Like the bimaristans, the goal is care that ordinary people can reach, whoever and wherever they are.

In Europe, people with mental illness were at times accused of witchcraft, chained in asylums or kept away from society. Fear and shame built up over centuries, and some of it lingers in jokes, words and silence today.

But history also shows change is possible. Reformers like Pinel, the Tukes and Dorothea Dix pushed for humane care, and today’s services increasingly focus on safety, choice and respect.

Small ways to help undo stigma

• Gently challenge myths, like mental illness being a curse or a weakness.
• Say “a person with depression” rather than defining someone by a condition.
• Share that you have sought help, if and when it feels safe.
• Use kind, plain words instead of slang like “crazy” or “psycho”.

Examples across time

• Bimaristans were often funded by charitable endowments and cared for the poor at little or no cost.
• Peer support today uses lived experience to help others recover.
• The York Retreat was founded by and for a faith community, the Quakers.
• WHO’s mhGAP programme helps everyday health workers, not just specialists, offer care.

How community helps today: faith groups, neighbours, support groups and peer workers can share the load so no one carries it alone. See the “Community care & belonging” guide for ideas.

Historians warn against reading the past only through today’s eyes. Many past healers were wise and caring for their time, even when their theories (like the four humours) turned out to be wrong.

The opposite mistake is over-claiming. For example, scholars say al-Balkhi described ideas similar to today’s cognitive therapy, but they caution against saying he “invented” CBT, since his world and words were very different from ours.

Questions to ask about any history claim

• Does it give credit fairly to people from many cultures?
• Does it judge people only by today’s standards?
• Is it based on historians and original texts, or on a meme?

Until the 1960s, psychology was largely run by men, and most research was done on men. Pioneers like Mamie Phipps Clark, Kenneth Clark, George I. Sánchez and Martha Bernal pushed the field to be fairer and more accurate.

Psychology’s history is also wider than Europe and North America. Healers and scholars in Egypt, India, China and the Muslim world all thought deeply about the mind, long before the first psychology lab opened.