People talk about the fact that black people score 15 points less than white people
What do you think of this kind of 'numbering'?
It's a fact, his meaning is totally unclear
and whose existence does not in any sense specify the cause.
Take the black-white difference in America which is on average 15 points
which is one standard deviation, by definition.
A test is standardized, so that 15 points will be the standard deviation.
That is true, nobody denies that, the issue is never been that,
the issue has been: "Why"?
And the existence does not tell you anything about "Why".
The existence of the 15 point difference is thoroughly consistent
with the two utterly extreme interpretations, namely nature and nurture,
that is in principal, it could be so - I don't think it is - 
that the differences due to inborn capacities that vary between the races,
and the other obvious explanation is
that the differences due to the enormous social disadvantages that the legacy in history of racism
continues to impose upon the lives of black people in the United States.
Either explanation would equally well account for the difference,
so it is a fact whose meaning is totally unspecified by the existence of the fact itself.
Why is the American society so obsessed with IQ?
I don't know if it is 'obsessed' by it,
but I think it arises largely in the context of the lamentable history of our racism.
I don't know that it is as much an issue in more homogeneous societies.
but we have a situation based on a legacy of racism
and continued oppression of people of African descent in this country
that has led, thus social reasons, to poor average performance of blacks on these tests.
That does not tell you why it happens.
But in a basically racist climate in a country with a strong racist history,
I suppose it is not surprising that particularly conservative social thinkers
would try to relate poor performances of blacks
to intrinsic biological limits.
Do you mean that measuring IQ is used as an instrument for racist...
It has been in the past, I don't think it is much used that way.
Now in fact I'm not sure that IQ in the old fashion sense
is much measured by mental testers at all today,
except if you read Herrnstein and Murray's "The Bell Curve" 
clearly these data still exist.
I just did not think that many people granted that number much meaning anymore.
As I like to put it,
the quick critique on "The Bell Curve" is that it is based upon four assumptions,
all of them have to be true,
if any one of them is false, the whole argument collapses.
First, there has to be a meaningful single number that can be given to intelligence,
and that is false.
Secondly, you have to be able to rank people in a singular linear order upon it,
and that order has to then correlate with social attributes
whether you are in prison or not, whether you have children out of wedlock, etcetera,
your income.
Thirdly that number has to be highly heritable,
and fourthly, it has to be unchangeable,
or effectively unchangeable.
A lot of people confused the third and the fourth,
they assume that when it is something inheritable, it means it is unchangeable.
But that's false.
Suppose the first three were true - and they are not:
suppose there was a legitimate number,
you could rank people and it was highly hereditary,
it still could be very mutable.
For example, the obvious example is
I may have an inherited defect of vision
which is hundred percent inherited,
I go to a drugstore and buy a pair of eyeglasses,
and my vision is fine.
All the things could be true about intelligence.
The equivalence of buying a pair of eyeglasses is namely 
programs of remedial education might boost IQ
and the whole argument would collapse.
What do you think about testing children
to see what would be the best school to go to?
It comes on what you want to use it for.
Again, if you look at Binet's original intentions
setting up the IQ test, in 1905, 1906, when he did the first ones
You see, Binet was a French psychologist
and he was commissioned by the committee  of Education in France to devise a test
to find students who needed help.
That's why he did the test,
and his motives we entirely benevolent.
In fact he specifically argued against giving a hereditarian interpretation
because he understood that if you did that,
you had misinterpret the number as a limit, rather than an aid.
He wanted to use the number as an aid to identify children who need help,
so that they can be given help
and everything could b done for them,
whereas if you give the hereditarian interpretation,
then you identify a low score with people who can't be helped. 
The exact opposite occurs, you invert the original purpose.
So as long as Binet's original purposes are honored
the test can be use benevolently, and sometimes they are.
For example, tests are used usefully to help identify
people who have specific difficulties, like dyslexia, autism
or other forms of disability and learning.
There is nothing wrong with that!
The human mind does not work very well for certain questions.
We are very bad at probability,
we always make the dichotomous divisions of things into two.
One of the things we are very bad at
is when we are faced to something that is very complex,
as intelligence is, because it involves lots of different independent abilities,
the relationship between heredity and environment
and all these complex questions.
We have this terrible tendency to try to make things simple,
trying to get a single number.
There is a whole history in subject after subject
of trying to encompass complex and independent attributes with a single number
My colleague for example wrote a very interesting article showing how in soil science,
this is a totally different field...
People for decades got hung up on trying to get a single number
to measure the quality of soil,
there's no such thing as THE quality of soil,
this one is 51, this one 76.2,
they are just different things that soils can do.
The human mind is even more comlpex,
there is no number that can capture the quality of mind.
It's almost humorous to think that there is, but unfortunately
the assumption that we can do such a thing,
tied to the use of such theories by conservative social ideologies
has had profoundly negative consequences for the lifes of millions of people.
There are millions of people, particularly in this country
who have been told they can't do this,
who have been denied admission to this or that program
on the basis of a number which was falsely interpreted
as representing an intrinsic limit upon them, based on their biology,
but was in fact only a measure of social influences upon their lifes.
So unfortunately it is not funny when it had such tragic consequences.
And that is of course where we are upset over the fact that the issue seems to keep coming up,
because it has consequences, it hurts people.
