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  • Scientists in the nineteenth century discovered a lot about life and matter. But exactly what

  • kind of stuff is the human brain? That one wasand remainstricky.

  • The brain scienceswith experiments and therapies tied to biological theories of the

  • bodyemerged in the nineteenth century and came into their own in the early twentieth.

  • I'm Hank Green and it's time to look at someupsetting stuff.

  • [INTRO MUSIC PLAYS]

  • People have always had theories of the mind and psychological disorder, ormadness.”

  • Madness was often thought to be a divine punishment, an act of possession by spirits, or the result

  • of an imbalance of the humors.

  • Doctors and priests cared for people dealing with mental disorders. And as capitalism took

  • off in Europe, the mentally ill were moved from villages, where they were looked after

  • by families, to hospitals in citiespicture Bedlamrun by a new class of professional

  • mad doctors.”

  • But this wasn't psychology or psychiatry as we know it today. In fact, there really

  • wasn't a scientific study of the human brain or the astonishing mental activity it enables.

  • This only got going around the time of the Industrial Revolution, with the rise of the

  • therapeutic asylum, or mental hospital aimed at helpingand studyingthe mentally ill.

  • Doctor Philippe Pinel of the Bicêtre hospital in Paris often gets credit for creating the

  • modern asylum in the late 1700s by ordering the patients to be unchained.

  • Credit should actually go to the hospital superintendent, Jean-Baptiste Pussinbut

  • Pinel did advocate for moral treatment of patients rather than physical restraint. And

  • his generation of asylum doctors marked the beginning of a shift in thought from madness

  • to a medical condition of the mind.

  • But asylums and early psychiatry were only one part of the story. Nerve doctors treated

  • anxious private patients. And early neurology grew from doctors examining the brains of

  • criminals.

  • Over the 1800s, proto-neuroscientists shifted from offering moral explanations for madness

  • to material explanations tied to brains.

  • This interest in gray matter came in part from scientists such as Francis Galton who

  • looked for explanations about human behavior in physical bodies, and who sought to make

  • the life sciences more quantifiable and useful.

  • Unfortunately, Galton's version ofusefulwas eugenics, orimprovingthe human

  • species through selective breeding. And scientists in the 1800s tended to blur the lines between

  • mental illness, crime, low intelligence, and a difficult childhood. So moral explanations

  • for mental illness snuck back into medicine viabad brainsinstead of religion.

  • Several researchers looked for connections between the physical brain and the mind. English

  • neurologist John Hughlings Jackson, for example, studied epilepsy and influentially argued

  • that different bodily functions are tied to different regions of the brain.

  • And German doctors Gustav Fritsch and Eduard Hitzig electrically stimulated parts of the

  • exposed brains of dogs, making their paws twitch. This showed experimentally that specific

  • parts of the brain coordinate motor functions.

  • And then we've got a name you've heard!

  • Russian physiologist Ivan Pavlov focused on conditioned reflexes: he taught dogs to associate

  • the sound of a metronome with being fed, causing them to salivate when presented with the sound

  • alone.

  • Pavlov's stimulusresponse work became foundational to the school of psychology called

  • behaviorism. With this approach, psychologists focused on environmental stimuli that affect

  • how someone behaves rather than what they're thinking and feeling.

  • Meanwhile, Spanish neuroscientist Santiago Ramón y Cajal developed a method of staining

  • brain tissue and discovered that it is made up ofwait for itindividual cells! Just

  • like the rest of the body.

  • After much painstaking lab work, he convinced the rest of the scientific community of this

  • idea, called theneuron doctrineafter the name of the brain cell.

  • Around this time, other researchers set up scientific laboratories to study the workings

  • of the human mind. BTW, we're mostly focusing on the mind today, but we'll talk more about

  • the brain after World War II.

  • German doctor Wilhelm Wundt founded the first psychology lab, at the University of Leipzig,

  • in 1879, establishing psychology as a discipline separate from other sciences.

  • Wundt's student, British psychologist Edward Bradford Titchener, developed a structuralist

  • psychological theory based on Wundt's ideas starting in 1892. Structuralism is a philosophy

  • that tries to understand things by seeing how their parts fit together, regardless of

  • what they do. Titchener tried to define theunit elementsof consciousness, hoping

  • to work out a periodic table for the mind.

  • Meanwhileheavily influenced by Charles DarwinAmerican philosopher William James

  • developed functionalism theory, writing the Principles of Psychology in 1890. Functionalism

  • is a philosophy that tries to understand things by working out the purpose for them.

  • Finally, American psychologist G. Stanley Hall, who studied under both Wundt and James,

  • set up the experimental psychology lab at Johns Hopkins and went on to professionalize

  • the whole field. He started the American Journal of Psychology in 1887 and founded the American

  • Psychological Association in 1892.

  • Thus, by the early 1900s, both the scientists studying brains and nerves, and those studying

  • consciousness and human behavior had set up professional labs to explore shared research

  • questions.

  • But the sciences of the brain and mind became more well known due to the application of

  • psychological theories outside of the lab. Y'all know who I'm talking about, right?

  • Austrian physician-turned-talk therapist-turned-controversial philosopher Sigmund Freud became so famous

  • that historians sometimes call the twentieth centurythe Freudian century.”

  • To introduce him, let's head back to 1862, when Europe's most famous brain doctor,

  • JeanMartin Charcot, worked at Paris's Salpêtrière hospital, then the largest in

  • the world.

  • Charcot saw patients but was also a big-time brain collector. And he realized that maybe

  • there were other, new ideas worth trying. His blend of brain research-plus-therapy,

  • the clinico-anatomical method, was the basis for Freud's work.

  • Charcot focused on trying to understand thelawsgoverning hysteriawhich has

  • a long, problematic history and isn't a disease today.

  • But back in the nineteenth century, it was a way of describing various problems, including

  • loss of motor control, paralysis, unexplained fears, fainting, emotional outbursts, and

  • a host of other ailments. It was a diagnostic trash can. Plus, a way to describe

  • women with independent ideas!

  • Charcot tried out a lot of methods: he was one of the first users of the camera in medicine,

  • moving toward mechanical objectivity, or trusting instruments over human senses.

  • A lot of his photos of hysteric patients were lurid and super weird by today's standards.

  • But the point of the history of science isn't to prove how awesome and ethical we are today,

  • but to understand how people in the past made sense of their worlds.

  • Charcot also explored mesmerism, or hypnosis. He showed that hypnosis can cause physical

  • symptoms, which he took to prove that hysteria was a neurological, not a psychological illness.

  • That is, he thought people with mental illnesses were more likely to be affected by hypnosis

  • because they had bad physical brains.

  • In 1885, the young Freud attended Charcot's lectures on hysteria and became obsessed with

  • mental illness.

  • Now, it's important to understand the halfway position that Freud occupied in medicine.

  • He couldn't take an M.D. in Germany because he was tooJewish. Instead, he became a

  • nerve doctor,” treating neurasthenia, or bad or exhausted nerveswhich was the

  • rich-person term for hysteria.

  • But he was open to new ideas. Freud learned a lot from Charcot. But then he found out

  • that Josef Breuer, a senior nerve doctor in Vienna, was using hypnosis to encourage patients

  • to talk rather than move.

  • Freud started working with talk therapy and realized that many hysterical patients were

  • smart and otherwisenormal.” And those suffering from hystericalparalysis

  • were paralyzed in ways that didn't make anatomical sense. He decided that hysterical

  • paralysis was not an anatomical problem.

  • In 1893, Breuer and Freud published Studies on Hysteria, theorizing that mental disorders

  • are not the result of bad biology but bad memories, such as sexual abuse. They suggested

  • that the best therapy was helping them recover those memories, which were often suppressed.

  • Breuer and Freud fell out, but from their work together, Freud developed a new form

  • of therapy, psychoanalysis, that caught on worldwide.

  • Help us out, ThoughtBubble:

  • Psychoanalysis was based on talking about early childhood experiences, relationships

  • with parents, early sexual encounters, and dreams. The couch became a therapeutic tool.

  • And dreams became important for therapists after Freud's influential 1900 book, Interpretation

  • of Dreams.

  • Through his work listening to patients and trying to decode their anxieties, Freud also

  • opened up the study of sexualityor, to coin another big question: where do funny

  • feelings come from? For Freud the answer was a form of psychic energy called libido that

  • floated around the brain and had to go somewhere.

  • Eventually, Freud's work led him to develop a three-part framework for how the human mind

  • functions and what it even is:

  • At the bottom, there is a fairly animalistic layer called the id or unconscious drives,

  • deep-seated fears and desires.

  • Above that sits the ego, or the waking, conscious mental interface with reality. Hey, it me!

  • And finally, metaphorically on top of the ego sits the superego, the mind's internalized

  • censor and the voice of society, religion, and moral norms.

  • For Freud, our minds are the outcome of a conflict between these basic desires, rational

  • desires, and social desires. Thisiceberg theoryof consciousnessthat we only

  • understand a small part of our own mindshas had an enormous influence on popular culture.

  • Thanks ThoughtBubble. Freud emphasized that this was not an anatomical model, but a medical

  • one, intended to help therapists access their patients' unconsciousness, and a sociocultural

  • one that accounted forall of history and religion.

  • To Freud, civilization represses sexual and aggressive drives, so it's a necessary evil.

  • Butwas this sort of theorizing even still science?

  • Regardless, psychoanalysis blew up. And Freud treated it as a foregone success: in 1914,

  • he publishedmaybe a little prematurelyOn the History of the Psychoanalytic Movement.

  • Something else happened in 1914: the Great War, or World War I, broke out. Over the next

  • four years, thousands of soldiers returned from the front complaining of sensory and

  • motor disorders and loss of memories, but with no obvious physical causes.

  • This becameshell shock,” later rethought of as post-traumatic stress disorder. Talk

  • therapists played a role in treating soldiers, and psychiatrists found a steady source of

  • patients.

  • Freud also continued to collaborate with other psychologists. His Swiss colleague Carl Jung

  • invented the word association test and the theory of the collective unconscious, or a

  • deep part of the mind supposedly derived from ancestral memory and myth, not individual

  • experience.

  • And Freudian ideas entered mainstream psychiatry through Swiss psychiatrist Eugen Bleuler,

  • who coined the termschizophrenia.”

  • The mind sciences found perhaps an even more fertile home in industry. Advertisers including

  • Freud's nephew, Edward Bernays, adopted theories of mind and behavior in order to

  • sell consumers increasingly mass-produced goods. And J. B. Watsonthe founder of behaviorismbecame

  • an advertising executive.

  • In a way, Freud helped sell Fords. And other industries looked to theories of mind in order

  • to make their organizations run more smoothly.

  • Next timelet's get radioactive with a legit family of geniuses: it's time to meet

  • Marie Curie.

  • Crash Course History of Science is filmed in the Dr. Cheryl C. Kinney Studio in Missoula,

  • MT and It's made with the help of all of these nice people. Our animation team is Thought Cafe