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  • Smarty pants, egg head, brainiac.

  • You've heard terms like these before, maybe you've even been on the receiving end of one

  • of them.

  • But actually, defining intelligence is a lot trickier than just coming up with new names

  • for smart people.

  • I mean, intelligence isn't like height or weight; you can't just toss them on a scale

  • and give it an exact measurement.

  • It has different meanings for different cultures and ages and skill sets.

  • So what is intelligence?

  • It's a question that doesn't give us a lot of answers, but it does open a bunch of other

  • equally important and interesting questions.

  • Like, what influences it?

  • And how can it be assessed?

  • Is it a single, general ability, or does it cover a range of aptitudes and skills and

  • talents?

  • How do things like creativity and innovation factor in?

  • Or genetics or environment, or education?

  • And what about emotional intelligence?

  • Most agree that it's best to think of intelligence not of a concrete thing so much as a concept,

  • the ability to learn from experience, solve problems, and use knowledge to adapt to new

  • experiences.

  • We've often used intelligence tests, to assess and compare mental aptitude, but these tests

  • have a long, complex and dark history.

  • I mean there are Nazis involved so, yeah.

  • So as you'll see, there are reasons that intelligence is one of the most hotly debated subjects

  • in psychology.

  • It's complicated and controversial.

  • [Intro]

  • What if I'm the world's greatest Rubik's cube solver but a terrible speller?

  • Or a truly gifted artist who's barely mastered long division?

  • Could anyone say I was intelligent or not based on those different aptitudes, or would

  • it be more accurate to measure my brainpower on several different scales?

  • Around the turn of the twentieth century, British psychologist Charles Spearman suggested

  • that yes, we do have one comprehensive general intelligence that underlies all of specific

  • mental abilities.

  • He called it the G-Factor.

  • Spearman conceded that while people may have special talents like basket weaving or saxophone

  • solos or doing crossword puzzles, those things still fell under "G".

  • And he helped develop a statistical procedure called factor analysis to try to determine

  • how certain clusters of skills might correlate with another one.

  • Like, say someone who tests well in spatial skills might be good with numbers.

  • We might then refer to that cluster of skills, that factor, as spatial-numeric reasoning.

  • But to Spearman, the G-factor was something of an uber-factor connected to all intelligent

  • behavior from architecture to healing to survival skills, and it's why people who do well on

  • one kind of cognitive test tend to do well on others.

  • But as you can imagine, reducing intelligence to a single numerical test score was and is

  • problematic.

  • L.L.

  • Thurstone, an American pioneer of psychometrics and one of Spearman's first challengers, was

  • not into ranking people on a single scale.

  • Thurstone administered 56 different tests to his subjects then used them to identify

  • seven clusters of mental abilities.

  • By this system, you might turn out to be great at like verbal comprehension but less stellar

  • at something like numerical ability.

  • Sounds fair.

  • But when researchers followed up on his findings, they actually did see that high scores in

  • one aptitude usually meant good scores in the others, essentially backing up some evidence

  • for some kind of G-factor.

  • Even though their ideas did not often align, Spearman and Thurstone together paved the

  • way for more contemporary theories on intelligence.

  • For example, American psychologist Howard Gardner views intelligence as multiple abilities

  • that come in different forms.

  • He references instances of brain damage where one ability may be destroyed while others

  • stay perfectly intact.

  • Savants usually have some limited metal abilities but one exceptional ability when it comes

  • to like, computing figures or memorizing the complete works of Shakespeare.

  • To Gardner, this suggests that we have multiple intelligences beyond the G-factor.

  • In fact, he believes that we have eight intelligences, ranging from our skills with numbers and words

  • to our ability to understand physical space and the natural world.

  • American psychologist Robert Sternberg tends to agree with Gardner, though he boils them

  • down into three intelligences: analytical, or problem-solving intelligence, creative

  • intelligence, or the ability to adapt to new situations, and practical intelligence for

  • everyday tasks.

  • Both of these models seem reasonable, too, and Gardner and Sternberg's work has helped

  • teachers appreciate students' variety of talents.

  • But research has suggested that even these different ways to be smart are also linked

  • by some underlying general intelligence factor.

  • So what about other less tangible forms of intelligence, like creativity, our ability

  • to produce ideas that are both novel and valuable?

  • How can a test that demands one correct answer account for more creative solutions, so-called

  • "divergent thinking".

  • Well, traditional intelligence tests can't, and so far, while we do have some tests that

  • look at creative potential, we don't have a standardized system for quantifying creativity.

  • But Sternberg and his colleagues have identified five main components of creativity, which

  • are useful for framing our understanding of what creative intelligence is and how it works.

  • If you go through the list, you know who I think is really great at almost all of them?

  • Sherlock Holmes.

  • Hear me out.

  • First we've got expertise, or a well-developed base of knowledge.

  • This just means knowing a lot about a lot.

  • Whether it's arcane poisons, jellyfish behavior, or how to recognize a secret passage behind

  • a book shelf, expertise provides the mind with all sorts of data to work with and combine

  • in new ways.

  • Obviously Sherlock has incredible imaginative thinking skills, too, which provide him with

  • the ability to see things in new ways, recognize patterns and make connections.

  • He loves nothing more than rehashing these breadcrumb trails for the dopey constables

  • at the end of the case.

  • Sternberg also thought a venturesome personality contributes to creativity.

  • By hanging around opium dens and chasing thugs and generally courting danger, Sherlock routinely

  • seeks new experiences, tolerates risk, and perseveres in overcoming obstacles.

  • And everyone knows he's driven by intrinsic motivation.

  • I mean, he wants to help the widow discover the thief and everything, but really, Sherlock

  • is driven by his own interest and sense of challenge.

  • He gets pleasure from the work itself.

  • And finally, Sherlock benefits from a creative environment which sparks, supports, and refines

  • his ideas.

  • For so affectionately maintaining this environment on Sherlock's behalf, we largely have Dr.

  • Watson to thank.

  • Sherlock was obviously an academic and creative genius, but he was pretty weak in another

  • form of intelligence: the emotional kind.

  • Emotional intelligence, defined in 1997 by psychologist Peter Salovey and John Mayer

  • -- no, not, not that one-- is the ability to perceive, understand, manage, and use emotions.

  • I don't know about you, but I know plenty of smart people who have a hard time processing

  • social information.

  • The most brilliant mathematician may struggle to communicate with colleagues, neighbors,

  • or staff at the local deli.

  • Likewise, Sherlock often annoys, offends, or even baffles those around him.

  • Perceiving emotions means being able to recognize them in faces, and even in music, film, and

  • stories.

  • Understanding emotions relates to being able to predict them and how they might change.

  • And managing emotions comes down to knowing how to appropriately express yourself in various

  • situations.

  • And finally, emotional intelligence also means using emotions to enable adaptive or creative

  • thinking; like knowing how to manage conflict or comfort a grieving friend or work well

  • with others.

  • Much like creative intelligence, emotional intelligence can be measured to some degree

  • through testing, but there's no standardized way to, like, assign a numerical value.

  • So if we can't perfectly quantify things like creativity or emotional smarts, how did we

  • come up with a way to measure intelligence?

  • Well, as I mentioned earlier, it's a sordid story.

  • The first attempts to do it in the western world began with English scientist Francis

  • Galton in the 1800s.

  • Taking a page from his famous cousin Charles Darwin's theories on natural selection, Galton

  • wondered how that premise might extend to humans' natural ability when it came to intelligence.

  • He suggested that our smarts have a lot to do with heredity, so if we encouraged smart

  • people to breed with each other, we could essentially create a master race of geniuses.

  • If that sounds a little sketchy, it's because it was, like, really, really sketchy!!

  • This study of how to selectively and supposedly improve the human population, especially by

  • encouraging breeding in some people and discouraging it in others, is called "eugenics".

  • A term Galton himself coined, and I'll get back to, in a minute.

  • But around the turn of the twentieth century when eugenics was taking off, the French government

  • mandated that all children must attend school.

  • Many of these kids had never been in a classroom and teachers wanted to figure out how they

  • could identify kids who needed extra help.

  • Enter Alfred Binet and Theodore Simon, two French psychologists who were commissioned

  • to develop a test to measure a child's so-called mental age.

  • The concept of a kid's mental age is essentially the level of performance associated with a

  • certain chronological age.

  • So if six year old Bruno tests as well as the average six year old, he'd have a mental

  • age of six.

  • Binet believed that his tests could measure a child's current mental abilities, but that

  • intelligence wasn't a fixed, inborn thing.

  • He believed a person's capabilities could be raised with proper attention, self-discipline

  • and practice.

  • In other words, he was no eugenicist.

  • He was hoping that his tests would improve children's education by identifying those

  • who needed extra attention.

  • But Binet also feared that these tests would, in the wrong hands, be used to do just the

  • opposite: labeling children as "lost causes", limiting their opportunities.

  • And wow, was he on to something because that is pretty much exactly what happened.

  • German psychologist William Stern used revisions of Binet and Simon's work to create the famous

  • intelligence quotient, or IQ measurement.

  • At the time, your IQ was simply your mental age, divided by your chronological age, multiplied

  • by a hundred.

  • So for example Bruno is six, and so is his mental age, so his IQ ranks at a hundred,

  • but his little sister Betty is a four year-old with a mental age of five, so her IQ would

  • be 125.

  • That formula works pretty well for measuring kids, but it falls apart when it comes to

  • adults who don't hit measurable developmental steps like kids do.

  • I mean there's no real difference between a mental age of 34 and 35.

  • But Stanford professor Lewis Terman started promoting the widespread use of intelligence

  • tests in the early 1900s, and with his help the US government began the world's first

  • massive ministration of intelligence tests, when it assessed World War I army recruits

  • and immigrants fresh off the boat.

  • Unlike Binet, Terman did use these numerical findings as a kind of label, and he thought

  • his tests could, as he put it: "ultimately result in curtailing the reproduction of feeble-mindedness".

  • This kind of testing played right into eugenicists' sensibilities, and soon the eugenics movement

  • in the US had a pretty good fanclub, raising money from the Carnegie's and Rockafeller's

  • and with proponents working at Harvard and Columbia and Cornell.

  • In the first half of the 21st century, intelligence tests were used to enforce the sterilization

  • of about 60,000 people, around a third of whom were in California.

  • Most were poor white women, often unwed mothers or prostitutes.

  • Other eugenics efforts persisted later into the century, and there is evidence of poor

  • African American, Native American, or Latina women being forcibly or covertly sterilized

  • in large numbers as recently as the 1970s.

  • But do you know who really loved their eugenics?

  • The Nazis.

  • Hitler and his cronies took the idea of intelligence testing to even darker conclusions.

  • The Nazis were all about selecting against so-called "feeble-mindedness" and other undesirable

  • traits as they sought to strengthen what they saw as their Aryan nation.

  • They sterilized or simply executed hundreds of thousands of victims based of their answers

  • to IQ test questions that were really more abut adhering to social norms than measuring

  • actual intelligence.

  • Questions like: "Who was Bismarck?"

  • and "What does Christmas signify?"

  • So you can see how this terrifying history still makes some people leery of how such

  • tests are administered, interpreted, and weighted.

  • Today we understand that intelligence, as defined by all the people we've talked about

  • here, does appear to be a real and measurable phenomenon.

  • But no one can say that they've disentangled all of the would-be genetic, environmental,

  • educational, and socio-economic components of it.

  • In the end, it's best to think of intelligence as something about which we've still got a

  • lot to learn.

  • And next week, we'll talk about how we test intelligence today and the problems we still

  • face in doing it.

  • Today, your intelligent mind learned about the history of how we think about and define

  • different types of intelligence, what the G-factor is, and how Sherlock Holmes is incredibly

  • intelligent but emotionally unintelligent.

  • You also learned about the history and methods of intelligence testing, IQ scores, and how

  • eugenics turned to the dark side, and has since made even talking about intelligence

  • kind of controversial.

  • Thank you for watching, especially fto our Subbable subscribers who make Crash Course

  • possible.

  • To find out how you can become a supporter, just go to Subbable.com/crashcourse.

  • This episode was written by Kathleen Yale, edited by Blake de Pastino, and our consultant

  • is Dr. Ranjit Bhagwat.

  • Our director and editor is Nicholas Jenkins, the script supervisor is Michael Aranda, who

  • is also our sound designer, and the graphics team is Thought Cafe.

Smarty pants, egg head, brainiac.

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