The Genetics of Intelligence

Published: 6.23.2017
Level 6   |   Time: 8:06
Accent: Canadian
Source: Quirks & Quarks (6.03.2017)

TOEFL: Two professors offer contrasting opinions on recent research concerning how genetics affects a person's intelligence.


You can download the file [ HERE ].


triangle Directions

  1. REVIEW the vocabulary.
  2. LISTEN to the audio above.
  3. ANSWER the questions.
  4. CHECK your answers (Show Answers)

triangle Vocabulary

  • a notion [n] - an idea
  • DNA [n] - part of a chromosome that carries genetic information (deoxyribonucleic acid)
  • exploit [v] - take advantage of / use
  • violate [v] - breaks / doesn't follow
  • inheritability [n] - ability to be inherited (genetically)
  • general cognitive ability [exp] - intelligence
  • substantially [adv] - largely / significantly
  • a gene [n] - the physical unit of genetics
  • delving deep [exp] - examining closely
  • ghosts of the past [exp] - problems in the past
  • eugenics [n] - the science of improving humans by controlling breeding
  • pick (stuff) up [phv] - learn
  • variance [n] - difference / variability
  • grit [n] - courage / strength
  • literacy [n] - ability to read
  • numeracy [n] - ability to do math
  • seedy history [exp] - negative/ugly history
  • grizzly apex [exp] - violent climax/high point
  • nature-nurture [exp] - genetics vs. environmental
  • schizophrenia [n] - a mental disorder
  • intervene [v] - interfere / affect
  • carve up [phv] - divide / separate
  • a genome [n] - a complete set of genes
  • strikes me [exp] - makes me think
  • a genotype [v] - the genetic composition of an individual
  • lead [exp] - a heavy metal (Pb)
  • racial groups [exp] - ethnic groups / races
  • genetically predisposed [exp] - have a tendency due to genetics
  • offensive [exp] - causing someone to feel upset or angry
  • oppressive narrative [exp] - a well-known but unfair/racist set of beliefs
  • less well-off [exp] - not rich
  • lurking in the shadows [exp] - (a negative thing) hiding and waiting to attack

[n] - noun,  [v] - verb,  [phv] - phrasal verb,  [adj] - adjective,  [adv] - adverb,  [exp] - expression

triangle Comprehension Questions

  1. How does the host describe the idea that some people's DNA makes them smarter?

  2. What is the movie Gattaca about?
    The origins of space travel
    People's genetic advantages
    How to become smarter

  3. How long have scientists been studying the (in)heritability of intelligence?
    less than 100 years
    100 years
    more than 100 years

  4. According to Professor Plohman, what percentage of people's differences in intelligence come from differences in their DNA?
    Almost none
    At least half
    Almost all

  5. According to Professor Plohman's study, how many genes are related to intelligence?

  6. What aspects does the host say the talk will focus on?
    Economic aspects
    Social aspects
    Ethical aspects
    Geographic aspects

  7. What does the host mean by "genetic discrimination"?
    Choosing the best genes when making babies
    Using genetic information to discriminate against people
    Supporting antipoverty ideas
    Studying the genetics of only some races

  8. Which of these statements does Professor Plohman make?
    Intelligence is the ability to learn.
    Some children learn faster than others.
    The best class size is 30 students.
    Class size has very little effect on children's ability to learn.
    Boys are better at math than girls.
    Genetics is the most important single factor for intelligence.
    We should blame schools and teachers instead of children when children have trouble learning.
    Children with low intelligence are usually unmotivated.
    Some children require a lot more effort to educate than others.
    Teachers should stop some children from reading so much.

  9. What has Dr. Tavery mainly studied?
    The manipulation of genes
    The genetic differences between races
    The ethics of studying genetics

  10. Who was Francis Galton related to?
    Charles Darwin
    James Tavery
    Robert Plohman

  11. What was the original meaning of the word "eugenics"?
    Gene study
    Good birth
    New genes

  12. What does Dr. Tavery say about the history of eugenics?
    It has a dark (negative) history.
    It was related to the (Jewish) holocaust in Nazi Germany
    It was started by Francis Galton.
    It was never studied in the US or Canada.

  13. What is the nature-nurture debate?
    The debate over the origin of eugenics
    Whether genetics or environment factors are more important in shaping your personality
    The way in which people inherit their genetic traits

  14. How does Dr. Tavery describe the study of genetics related to intelligence?

  15. What is Dr. Tavery afraid of?
    Children will be judged and separated based on their genes.
    Children will lose access to good education.
    Children will be forced to change their genes.

  16. What does Dr. Tavery think are the best ways to help children?
    Put genetically superior children in special schools.
    Give extra help to children with fewer intelligence genes.
    Improve the quality of children's drinking water.
    Give children more books.

  17. In a 2014 study, how many genes did scientists find related to intelligence?

  18. What did other scientists use the 2014 study for?
    To show that some racial groups had more of the intelligence genes than others.
    To improve education for different racial groups
    To demonstrate the value of genetic engineering

  19. Why does Dr. Tavery say that using the study is problematic?
    People will use the study to show that some races are more intelligent than others.
    People will use the study to show that some people are poor because of genetic factors.
    People will use the study to stop research into genetics.

  20. What does Dr. Tavery promise will happen next?
    Further research on the genetics of intelligence will be stopped because of fear of racism.
    Someone will do a study to determine which racial group has the highest number of the 52 intelligence genes.
    Schools will start using the research to start making special classes for more intelligent students.

triangle TOEFL Questions

  1. What is the main topic of the lecture?
    (A) The ethics and usefulness of studying intelligence
    (B) How children differ genetically
    (C) The history of unethical scientific study
    (D) The origins of eugenics

  2. The host mentions the movie Gattaca in order to ____.
    (A) show some of the problems that can arise from studying genetics
    (B) give an example of an undemocratic future
    (C) show how DNA affects intelligence
    (D) tell the audience about one of his favorite movies

  3. According to Professor Plohman, the inheritability of intelligence ____.
    (A) has been clearly understood for a long time
    (B) has recently been discovered
    (C) is still in doubt
    (D) is not important

  4. Professor Plohman states that up to 50% of general cognitive ability ____.
    (A) is controlled by the quality of education
    (B) is genetically different
    (C) is determined by class size
    (D) is determined by genetics

  5. 52 genes have been shown ____.
    (A) to control all human intelligence
    (B) to be connected to human intelligence
    (C) to be present in only intelligent people
    (D) to be present in only certain racial groups

  6. Why does the host mention eugenics?
    (A) He wants to show a difference between past and present research into intelligence.
    (B) He wants to show a connection between intelligence and poverty.
    (C) He wants to show how this research can be used for unethical purposes.
    (B) He wants to show Charles Darwin's connection to this research.

  7. Professor Plohman states that ____.
    (A) intelligence is the ability to learn
    (B) children need good teachers to become intelligent
    (C) most children have similar learning abilities
    (D) intelligence is impossible to measure

  8. According to Professor Plohman, class size ____.
    (A) greatly affects a student's ability to learn
    (B) has little effect on a student's ability to learn
    (C) should be limited to improve the learning of students
    (D) should be limited to 30 students or less

  9. What does Professor Plohman mean when he says this?

    (A) It is difficult to stop children from studying.
    (B) Teaching children requires a lot of effort.
    (C) Most children have the same intelligence.
    (D) Children differ in their ability to learn.

  10. Dr. Tavery is mainly concerned with ____.
    (A) how children learn
    (B) what factors improve education
    (C) how people use intelligence research
    (D) why some racial groups are more intelligent than other racial groups

  11. Which of these statements about Francis Galton are true?
    [Click on three answers.]
    (A) He was related to Charles Darwin.
    (B) He was a Nazi.
    (C) He created the study of eugenics.
    (D) He was interested in the nature-nurture debate.
    (E) He believed intelligence was related to when you were born.

  12. Dr. Tavery suggests that it is a good idea _____.
    [Click on two answers.]
    (A) to put less intelligent students in special programs.
    (B) to try to make people more intelligent through genetics.
    (C) to help students by improving their water quality.
    (D) to determine which racial groups have genes related to intelligence.
    (E) to give students more books.

  13. Dr. Tavery states that intelligence studies ____.
    (A) should be stopped
    (B) can be used for unethical purposes
    (C) can help improve education
    (D) require more funding to be effective

  14. A similar study conducted in 2014 ____.
    (A) identified 13 genes related to intelligence
    (B) showed how some racial groups are more intelligent than others
    (C) was used by other authors to show racial difference in intelligence
    (D) helped schools improve their curriculums

  15. What does Professor Plohman mean when he says this?

    (A) The idea that poverty is related to genetics is racist.
    (B) There is a strong connection between intelligence and wealth.
    (C) Poor people are often oppressed because of genetics.
    (D) Poverty cannot be prevented.

triangle Script

It's hard to imagine an idea more uncomfortable than the notion that some people's DNA means they were born to be smarter than others. It's a discomfort exploited in the Hollywood science fiction thriller Gattaca. It paints a picture of a future in which your place in society is determined by the supposed advantages written into your DNA. It's a disturbing notion unfair, even undemocratic. It violates our notions of equality. And yet if you ask almost any behavioral scientist this is what you're likely to hear.

The heritability of intelligence has been studied for almost 100 years, and by now it's one of the most well documented findings in the behavioral sciences that individual differences in intelligence, say learning ability or general cognitive ability as it's called. Those individual differences are very substantially, at least 50 percent, are due to DNA differences between us. That is genetic differences, inherited DNA differences.

That's Professor Robert Plohman. He's a behavioral geneticist at the Institute of Psychiatry at King's College London. Two weeks ago, he and his colleagues released a study identifying 52 genes linked to human intelligence. Genes where small differences in the DNA code made some people smarter than others. Today we're going to spend some time delving deep into what this means scientifically of course, but also from a social and ethical perspective because this is an area where these issues couldn't be more important. That's because whenever we talk about the genetics of intelligence, we bring in the ghosts of the past and the fears for the future. Like eugenics, using genetic technologies to make quote unquote improved humans. Or questions of genetic discrimination, like using people's supposed genetic disadvantages to support racist or antipoverty political agendas. So to start, let's return to Professor Plohman.

Basically, intelligence is learning ability. And any teacher knows that given a class of 30 students, some of them just pick stuff up very quickly, and others have to struggle to pick things up. And that could be skills like reading and math, or it could be more general comprehension. Children just differ a lot. And teachers know it isn't just how well they teach. By finding genes, it'll make the genetics more real. I mean as I say we've known that intelligence is heritable for decades. The things we worry about in school, like class size, it accounts for less than 1 percent of the variance. Gender differences, differences between boys and girls in math and verbal, less than 1 percent of the variance. So we get all bent out of shape about those things, and we ignore something that accounts for more than everything else put together. There's still a lot to play for in terms of getting people to understand first to recognize how different children are and the extent to which genetic differences account for those differences. And then secondly to respect those differences to a greater extent, not to assume that a child who has difficulty at school. You first blame the schools then you blame the teachers and you blame the parents and failing all that, you blame the child for not being motivated not having enough grit or whatever it is. But we need to recognize that children really do differ genetically. And that doesn't mean we give up on children. We just recognize that it's going to take a lot more effort to get some kids up to minimal levels of literacy and numeracy, whereas other children, you can't stop them from learning to read or doing math.

For a somewhat contrasting perspective, I’m now joined by Dr. James Tavery. Dr. Tavery works in applied ethics and the philosophy of science at the University of Utah. He's written on the ethical implications of studying genes for intelligence. Dr. Tavery, welcome to Quirks & Quarks.

Thanks. Happy to be with you.

Now you've studied how the controversies in the study of intelligence have evolved over the years, so can you give me a brief summary of that and take me up to where we are right now?

The father of the nature nurture debate and really the science of studying nature and nurture was Charles Darwin's younger cousin, Francis Galton. Interestingly, Galton was also the father of eugenics, and when Galton created that term it just meant good birth. But eugenics has a very seedy history in the US and Canada, overseas. And of course you know it reaches its absolutely grisly apex with the Holocaust in Nazi Germany. And so Galton wanted to develop a science of nature and nurture, and he wanted to do that because he wanted to change the world. That's a hundred or more years ago. What you see is throughout that history throughout the 20th century and into the present, lots of people trying to figure out, for whatever trait you're interested in intelligent schizophrenia criminality, what's genetic what's environmental. And that's they're interested in that question because they want to use the answer to intervene. Right? They want to see more intelligence and they want to see less criminality. But the very act of trying to you know carve up the world and decide who's better and who's best and to assess that based on what's in our bodies what's in our genome can lead to really really bad things.

Dr. Plohman said that this might help us identify those who need help or those who might be at a disadvantage.

And that strikes me as extremely optimistic. With the 52 genes that we're talking about, everybody is going to have you know sort of some set of what we might think of as better and worse variants in there. And the reality is you know what they did was they found genes that were associated with IQ. But none of the cases do we know precisely how they create that trait that we're interested in. The thought that we could sort of you know genotype kids and say, “Oh you've got more than 30 of the bad ones. Maybe we should think about putting you in a special program.” No way. If you want to help kids, get the lead out of their water. If you want to help kids, get more books in their home. I mean there's so many very straightforward environmental interventions that we know are going to have a positive impact on intelligence.

Does this work reduce or increase the ethical concerns around research into the genetics of intelligence?

Well I wouldn't say a single study reduces or increases it. But I do think it's certainly a study like this lends itself to abuses. So let me give you an example. Many of these same authors were on a paper that came out in 2014 that also looked for areas of the human genome that were associated with cognitive ability. And they found three at that time. Almost immediately afterwards the next year, other researchers came along to look for whether or not those three genes had different distributions in different racial groups because what they were interested in is whether or not minority groups are sort of genetically predisposed to being less intelligent than white people. It's offensive and it contributes to a kind of oppressive narrative that people who are less well-off are less well-off because of something in their genomes. I can guarantee you, within the next five years, the 52 genes that have been identified in this study, somebody is going to come along and try to see if those 52 genes are distributed differently in different racial groups. And so you can't blame the study authors for that, but there is a sense in which the research that they're doing opens the door. These people are lurking in the shadows waiting for these studies to be done so that they can pursue their more racialist interests.

Dr. Tavery thank you very much for your time.

It was my pleasure. Thanks for having me.

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