20 juin 2017

Quotient intellectuel, intelligence et personnalité

Comme mes lecteurs de longue date le savent, j'adore qu'on bouscule mes idées préconçues. Et c'est ce qui est arrivé lorsque j'ai écouté cette fascinante conversation entre Sam Harris et Charles Murray.

Avant de l'écouter, si vous m'aviez demandé ce que je pense du quotient intellectuel, je vous aurais dit que c'est de la foutaise. Je vous aurais dit que l'intelligence n'est pas quelque chose qui peut être clairement définie et encore moins mesurée et chiffrée. Je vous aurais dit que l'intelligence d'un individu évolue pendant sa vie et que, comme un muscle, elle peut devenir plus efficace et plus puissante. Je vous aurais également dit que l'éducation des parents joue un rôle de premier plan dans le développement intellectuel des enfants.

Dans la même veine, je vous aurais affirmer sans hésiter que l'idée de comparer l'intelligence de différentes "races" est répugnante, que le concept même de race me semble périmé, que si un groupe ethnique réussit moins bien qu'un autre, cela est principalement dû à des problématiques sociales et pas à l'intelligence de ses membres.

Mais après avoir entendu cette conversation, je ne suis plus sûr de rien. Chacun des points ci-dessus est mis à mal par Murray et Harris, pour ne pas dire complètement anéanti. Et j'adore ça. Il faut absolument que je me tape ce livre.

Voici la conversation ainsi que quelques extraits notoires:

(31:12) "There is just this fact which is one of the most well attested facts in psychology that a person's ability to reason logically and mathematically and visual spacially along with their semantic knowledge of the world, the size of their vocabulary for instance, all of these abilities are highly correlated. It's this correlation which has been dubbed "general intelligence" and this is what IQ tests measure."

(35:05) "The role of IQ in explaining success, IQ has the same role as weight does in an offensive line in the NFL. If you take the starting linemen in the NFL and you correlate their productivity with their weight, the correlation's basically going to be zero. Because the heaviest linemen are not the best linemen. But you have to be 300 pounds to get the job. And that's the way with IQ. Motivation, what they now call grit, and a variety of other things are decisively important but if you're going to be a theoretical physicist, you have to weigh 300 pounds to begin with. And then, among theoretical physicists, these other qualities will be really important in determining how good you are." 

(38:34) "There is this notion that if traits are genetically determined, that's bad. And if traits are environmentally determined, that's good because we can do something about them. And if there is one lesson that we have learned from the last 70 years of social policy, it is that changing environments in ways that produce measurable results is really, really hard. We actually don't know how to do it, no matter how much money we spend."

(39:07) "Virtually everything important psychologically, these traits are highly heritable. This includes the big five personality traits: extraversion, agreeableness, conscientiousness, neuroticism and openness. A person's personality is about 50% ascribed to genetic inheritance and the rest to environment."

(39:45) "There's the shared environment and there's the non-shared environment. That's one of the things that the twins study has elucidated. It's the non-shared environment that takes up almost all of that 50% of personality characteristics that is not explained by genes. Non-shared environments can be all sorts of things. It can be you had different teachers in school, it can be you ran with different peer groups. It can also be that parents treat children differently. So the maternal warmth that a mother shows to one twin is sometimes much different than the warmth shown to another. But the thing about the non-shared environment is that it's not susceptible to systematic manipulation. It's idiosyncratic, it's non-systematic."

(41:10) "It is true that parents, (...) we resist that. With the non-shared environment and the small role left for parenting, I will say it flat out, I read that research with the most sceptical possible eye. I was looking for holes in it assiduously. (...) I don't know of anyone who's familiar with the litterature who thinks there's that much of a role left of the kind that parents thought they had in shaping their children."

(44:06) "There are many other things that IQ is correlated with. High IQ is correlated with things like liberal values, being less racist, less authoritarian, less sexist, even less religious, in particular less fundamentalist in your religiousity."

(46:00) "The right used to be kind of boosterish about IQ testing because it seemed to promise a direct road to meritocracy. It would get us out of these class differences and people could just be judged on their own merit."

(47:40) "Now ordinary people are perfectly comfortable with the idea that some people are smarter than others. They're perfectly comfortable that what we call smart gets you kinds of jobs you can't get otherwise. It's the elites who are under the impression that, oh, IQ tests only measure what IQ test measure, and nobody is really able to define intelligence (...) it's culturally biased, on and on. And all of these things are the equivalent of saying the Earth is flat. These are not opinions that you can hold in contest with the scientific litterature. (...) This stuff is not subject to debate anymore. The elite wisdom in colleges is that what I'm saying is pseudo-science. It's very frustrating."

(48:45) "You just referenced two things which are widely believed which are certainly known to be false. (...) The first claim is that IQ tests simply measure people's ability to take IQ tests. That is a shibboleth that is rattling around the brains of many of our listeners. No one in touch with the litterature has thought that was true for a generation. And then there's the idea that these tests are well known to be culturally biased, so that you just cannot get valid data on certain groups (...) That also is not the current opinion of psychometricians anywhere."

(49:35) "It's a matter of predictive validity. (...) If you're an employer and you have only one datum that you can get (...) You are better off knowing an IQ score than you are having a personal interview, having grades, having degrees or anything else. The single most informative thing you can have is an IQ score."

(54:08) "It's also widely believed that race is not a valid biological concept, it's a social construct. There are many ways to see this is untrue (...) It's not an accident that you can generally predict where a person's ancestors came from by sumply looking at his face. There are phenotypic differences between people that have genetic underpinnings and it's not just merely skin deep. There are genetic diseases that various racial groups have or are more prone to. (...) This is just straight biology."

(1:07:45) "To have political equality, you have to treat people as individuals. (...) The variance between individuals will be much higher than the variance between groups (...) The truth is that I learn nothing about a person's intelligence simply by being told that he's black or white or Asian. (...) There will be many many blacks who will be far more intelligent than most whites."

(1:10:48) "To give people a taste of the reaction you got to this book, the sociologist Steven Rosenthal called the book "a vehicle of Nazi propaganda wrapped in a cover of pseudo-scientific respectability, an academic version of Adolf Hitler's Mein Kampf." This was the tenor of the response even among intellectuals and academics who were reviewing the book."

(1:13:21) "We now have social policy embedded in employment policy, in academic policy which is based on the premise that (...) all groups are equal above the neck, whether it's men and women or wheter it's ethnicities. And when you have that embedded into law, you have a variety of bad things happen. (...) What social policy is doing in an employer's mind when it is a black candidate walking into that office is all sorts of things that are raising the cost of hiring that person (...) in terms of vulnerability to discrimination lawsuits, vulnerability to a variety of other regulatory penalties (...) because that person cannot be evaluated on that person's merits and the decision made solely on those merits without encurring risks."

(1:15:15) "There is a strong argument to be made that my colleague at AEI Christina Hoff Sommers has made, that education in recent years has been taken over by essentially an elite wisdom which has feminized education and changed k-12 education into something that boys don't thrive in and girls do. And the answer to that is not to go back into an old form of education which was based on how boys learned, rather it's important to recognize differences between men and women, boys and girls, that exist to do a good job of educating them. Throughout the way that we conduct our economic and educational lives and a lot of other institutions, the equality premise, that all groups of people only have differences in outcomes because of racism or sexism or inappropriate institutions, that assumption has created huge harm."

(1:22:24) "How would I feel if I were a black kid my age, going into college and everybody thought I was there because I was an affirmative action kid? I would hate that. How would I feel if, on the job, I knew that everybody assumed I got that job because of affirmative action? I would hate that. And I would try to do my best to prove them wrong but I find that morally repugnant."

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