Good Point

Taking a pragmatic stance: Believing that people are blank slates leads to better results when teaching. I'd be interested in an argument to the contrary.
I'd also be interested in any examples outside the field of education where believing that people are blank slates is sub-optimal, or even more interestingly, harmful.

I don't think anyone, anywhere, really believes the strong version of the blank slate theory, but I think that, sometimes at least, it can be a useful stance to take, while the opposite stance seems to me to be a lot less useful, and potentially a lot more harmful.

Assuming that people are blank slates in teaching will result in all students being taught the same, regardless of the fact that they may have different ways and rates of learning. It will bore the intelligent, and frustrate those who are having trouble keeping up. In other words, it will work the way the public school system does, with a lot of failure.

Belief that there is no difference in the genders, and that it is all social conditioning, results in things like treating a boy who was accidentally fully castrated like a girl, until he rebels later in life and recaptures his masculinity. This actually happened. It also results in nonsense like Title IX, where the assumption is made that not as many women like sports because of societal disapproval, rather than it simply being an average trait of women to not be interested in sports.

Believing that people are blank slates leads to better results when teaching.

Ugh. As someone who has taught thousands of students, I think you are disastrously wrong. On the contrary, you get much better results if you adapt the style, pace, and content of your teaching to the natural abilities, learning styles, and interests of your students.

And as a parent, I've also seen the unfortunate result of a foolish ignorance among teachers of the natural cognitive development of children. They seem to figure the time at which you can teach a child something has only to do with his preparation (prior teaching) and zero to do with how his brain's wired up at that particular age. Really stupid. You might as well try to teach them about sex in kindergarten.

And if you believe in cognitive development -- which you have to be an idiot not to -- I don't see how you can escape the corollary that cognitive development is very unlikely to be exactly the same (follow the same path at the same pace with the same end result) for everyone.

Really, I think intelligent people can only believe in "blank slates" as much as they seem to when they are blinded by some powerful other ideology. In the case of the Left, it seems to be the ancient "scientific socialist" canard that human beings are, or can be made to be, perfectly functioning smoothly interchangeable cogs in the social machine. But that kind of self-delusion can happen when you worship at the altar of collectivism, when you think the "we" is in every way and always better and more important than the "I" and "you" that comprise it.

Rand and Carl, I agree completely with both of you: teaching should be tailored to each student's individual abilities, and, ideally, their interests.

Let me offer the story that motivated my original comment. Most likely, you've both heard it, and I believe it is actually true, and not apocryphal: A class of students were given an IQ test at the beginning of the year, and teacher was given the scores, the stated rationale being that the teacher should know which students really did have great academic potential, even if they didn't always demonstrate it. At the end of the year, all of the high scoring students did, in fact, show marked improvement, even the ones who had been very poor students the previous year. It was then revealed that the IQ scores had been assigned to the class randomly. The teacher had simply given the students who had been assigned a high score extra attention. I'm sure I don't have to spell out the moral of this story.
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I don't believe even a strong advocate of the blank slate theory would need to subscribe to the idea that all students should be taught the same way. A blank slate theory advocate who was also a good teacher would simply presume that any differences in childrens' abilities had occurred because each child had had different learning experiences before they met that particular teacher.

I can see why you would find the blank slate theory ripe for abuse in a totalitarian regime that controlled its slaves from cradle to grave, but in a modern free society, a blank slate stance needn't dull a teacher's receptiveness to individual learning styles and individual cognitive differences among students.

What I was really getting at was the idea that rather labeling kids "gifted" or "average" or whatever, a teacher can benefit his or her students by assuming that all of them have very high potential. (And, fortunately, I don't think that makes me an evil collectivist!)

A blank slate theory advocate who was also a good teacher would simply presume that any differences in childrens' abilities had occurred because each child had had different learning experiences before they met that particular teacher.

But in that case, the advocacy of the blank slate theory is entirely irrelevant, since the teacher isn't teaching as though the slate is blank. The teacher is assuming that someone else has already written on it. So how does this square with your original statement that believing in blank slates leads to better results?

What I was really getting at was the idea that rather labeling kids "gifted" or "average" or whatever, a teacher can benefit his or her students by assuming that all of them have very high potential.

That's different than the tabula rasa theory, which is that all are the same. And even that's not optimal, because if the teacher wastes time on the kids who don't have high potential (and sadly, they do exist), time is take from those who actually do, and can use or need the attention of the teacher. We see this problem writ large in society with the large numbers of people in college who don't belong there, either because they can't handle it, or because they can be successful without it, or both.

I have to say, I would be just fine if you viewed my comments through a political lens. I think I'm representing _why_ Democrats might be more apt to believe in a blank slate theory - because they are hopeful about the human race; because they believe that given the right oppportunities, anyone can learn, and anyone can be a success. Your ruggedly indvidualistic ideology leads you to want to give up on people, liberals keep on hoping that improvement is possible, and the fake IQ story demonstrates that this hope can pay off.

P.S. Rand, I wrote this before I saw, in the preview, that you had already responded. I'll post this, and then I'll think about what you wrote.

But in that case, the advocacy of the blank slate theory is entirely irrelevant, since the teacher isn't teaching as though the slate is blank.

Rand, the original post posited that liberals don't believe in biology. I followed the links from the NRO post, but I must admit I didn't get much out of them (I stopped when I saw the comment that Jews and Chinese are smart because of genetics rather than culture....)

I took the "liberals don't believe in biology" to imply that a liberal teacher wouldn't believe that any of his or her students are inherently stupid or unable to learn. Now, obviously, in an extreme case of mental retardation, or worse, any liberal certainly would believe in biology, so I interpreted the argument as being about the classic "nature vs nurture" question. And I'm arguing that it is pragmatic for a teacher to come down on the side of "nurture", and be part of that nurturing experience, even if it is a scientific fact that genetics plays an enormous role in determining human cognitive abilities.

Your point of view leads to giving up on students. Since your original post was about political ideology and not education, I'll be deliberately provocative: your point of view has the potential to lead people to give up on democracy - after all, if some people are inherently inferior to other people, why should their voices count as much?

I think I'm representing _why_ Democrats might be more apt to believe in a blank slate theory - because they are hopeful about the human race; because they believe that given the right oppportunities, anyone can learn, and anyone can be a success.

Yes, and as in many other cases when policy and good intentions are out of alignment with reality, mischief, and even catastrophe can ensue.

I stopped when I saw the comment that Jews and Chinese are smart because of genetics rather than culture...

That's exactly what I mean. You don't believe that some people are smarter than others, and you don't believe that some genetic groups of people can be smarter than others on average. Do you have any reason to believe this, other than wishful thinking, and you simply don't want to believe it? Again, policies should be based on reality, not on feel-good ideology.

Your point of view leads to giving up on students.

No, my point of view means dealing with them appropriately. You try to treat everyone so that they can maximize the potential of their lives, but it makes no sense to attempt to teach calculus to someone with an IQ of 80. To assume that everyone has the same potential is disastrous, because resources, including instructors' time, are finite.

your point of view has the potential to lead people to give up on democracy - after all, if some people are inherently inferior to other people, why should their voices count as much?

So I should indulge others in a fantasy because otherwise people might draw bad policy conclusions from reality? That's like the argument of creationists that even if evolution is true, it makes people not believe in God or morality, so we shouldn't teach it.

In any event, this is not about "inferiority." When Jefferson wrote that all men were created equal, he didn't mean that they all had equivalent physical and mental capacity. He meant that they all had equal and unalienable natural rights. Those are what the franchise derives from, not from intelligence level.

I'm a firm believer in science, and having a world view that is in accord with evidence.

I'm just saying that you can get better results as a teacher if you believe in your students and keep trying pedagogically appropriate approaches. If you want to teach a poor student calculus, first, assume he isn't really a dullard, and second, walk before you run. It helps if you figure out how calculus is going to help the student acheive his goals, and present even the most introductory mathematics lessons with those goals in mind. I'm not convinced that someone who gets an 80 on an IQ test couldn't be successful at calculus. People don't have IQs, except in the sense that they take IQ tests at different times in their lives, and receive various scores.

The challenge for me is to make sure my first paragraph is in accord with my second paragraph. The challlenge for you is much harder: you have to stop thinking silly things about liberals!

I'm just saying that you can get better results as a teacher if you believe in your students and keep trying pedagogically appropriate approaches.

I agree. That has nothing to do with belief in a blank slate, which is that all people are born with equal capabilities, and that all learning and ability is cultural. You continue to shift back and forth.

The challenge for you is much harder: you have to stop thinking silly things about liberals!

No one has mentioned the word "liberal" in this post, or comments, except you.

I'm a firm believer in science, and having a world view that is in accord with evidence.

There is no evidence that everyone is born with the same intrinsic intelligence type and level, and ability to learn all subjects (one of the tenets of the blank slaters). All of the evidence is to the contrary.

Why are you resistant to the notion that (e.g., blacks) might be more intelligent, on average, than white? What scientific argument could you put forth to convince that all people are equal, and all genetic groups are equal?

Caveat: I am not a biologist. I'm going to do my best with this post. I will cheerfully accept getting shot down by someone who has verifiable mainstream biological information that contradicts what I'm about to write.

A good start would involve getting coming to an agreement on what you mean by "genetic group". Earlier in this thread, you seemed to be implying that "Chinese are smart" isn't completely laughable. Now you float the idea that you can compare "blacks" and "whites". Sorry, these categories don't have any meaning in biology, and moreover, in the case of "blacks" and "whites", there is no definition that makes any sense period. Pick any two "black" people at random. Now pick any "white" person at random. (You get to decide what counts as "black" and "white"). If the three people aren't closely linked by ancestry on a family tree, there is likely to be as much genetic difference between the two "black" people as there is between either of them and the "white" person.

In the case of "Chinese", you know full well that this category accounts for a sizable portion of the Earth's population and includes a vast number of genetic groups (for all likely definitions of "genetic group"). Again, the genetic diversity within the category is vast.

For "Chinese", "Whites", and "Blacks", if you stray outside the realm where political identity or self-identification are what defines group membership, you are doomed to talk nonsense at best, and you'll sound like a racist at worst.

In the case of "Jews", there are also no biologically relevent genetic defnitions. On the other hand, since it is true that most of the Jews you meet in the United States are Ashkenazim, and there have been genetic tendencies which have been found to be more widespread within that "group", the question of a genetic disposition for certain cognitivve abilities at least becomes worth asking about.

So, lets overlook questions involving recent conversion, and just suppose, for Ashkenazi Jews, it is true: lets suppose the genetic disorder that causes a risk of tay-sachs also selects for higher intelligence. So what? We know from personal experience that the generalization "Jews are smart" fails in individual cases. Until we can test for certain genes (or even engineer certain genes), the relevance to how we teach individuals seems pretty remote to me. And the point I was making wasn't that we should hide from science, but that our policies should be pragmatic.

A good start would involve getting coming to an agreement on what you mean by "genetic group".

It's a way of saying what most people think of as "race," even though that's not a biologically useful word.

Now you float the idea that you can compare "blacks" and "whites".

Shorthand for the above phrase, recognizing that it is horrifically imprecise.

On the other hand, since it is true that most of the Jews you meet in the United States are Ashkenazim, and there have been genetic tendencies which have been found to be more widespread within that "group", the question of a genetic disposition for certain cognitive abilities at least becomes worth asking about.

Yes, politically uncomfortable as it may be (and I have a great deal of that genetics myself on my father's side), that's what I am talking about.

So, lets overlook questions involving recent conversion, and just suppose, for Ashkenazi Jews, it is true: lets suppose the genetic disorder that causes a risk of tay-sachs also selects for higher intelligence. So what? We know from personal experience that the generalization "Jews are smart" fails in individual cases. Until we can test for certain genes (or even engineer certain genes), the relevance to how we teach individuals seems pretty remote to me. And the point I was making wasn't that we should hide from science, but that our policies should be pragmatic.

I agree with this entire paragraph. But that's because I'm an individualist, not a collectivist. Unlike most Democrats (and "liberals") I don't think that we should treat people as members of groups. I think we should treat them as individuals.

Yet despite that, you are uncomfortable with making general statements about the groups, to the point that you quit reading articles about them, even though there is a ton of empirical evidence that they are probably true.

I wonder why that is?

I should also note that in your long response you failed to answer the question: "What scientific argument could you put forth to convince that all people are equal, and all genetic groups are equal?"

Instead, you simply said that it didn't matter whether they were or not, because people are individuals. That is, you agree with me. Yet you persist in the blank slate fallacy.

You might want to think about that.

You lost me. If you're ideologically determined to be an individualist, what difference does this argument make anyway? And haven't you just flipped the whole post on its head? Wouldn't you, you personally that is, expect "the Right" to favor a blank slate theory, and wouldn't you expect "the Left" to shun it.

On race:
I quit reading an article that was making generalizations about "Chinese". And I was disagreeing with your notion that it might be worth talking about "whites" and "blacks" in a conversation about biology. Are you saying there is a ton (or even any) empirical evidence for the generalizations in question about "Chinese", "Whites", and "Blacks"? I wonder if you are thinking of "The Bell Curve". It has been years since I read various reviews completely debunking that book, and I'm not prepared to argue about that book specifically wihout doing some research (and reading the book!), but you can look for various debunkings online. Did it argue for a genetic basis for its findings? I can't remember. If so, without getting into the specifics of the book, the fact I described (but didn't cite) about the two randomly chosen "black" people and the randomly chosen "white" person should suffice to indicate how silly any genetic claims about "blacks" are. (If the fact about the randomly chosen people is true that is. I'm remembering it from a class in physical anthropology that I took in the 1980s.)

If you're ideologically determined to be an individualist, what difference does this argument make anyway?

Because there are many other reasons to shoot down the foolish notion that people are born as a blank slate?

And haven't you just flipped the whole post on its head? Wouldn't you, you personally that is, expect "the Right" to favor a blank slate theory, and wouldn't you expect "the Left" to shun it.

No, not at all. You'll have to explain this if you want it to make any sense.

I quit reading an article that was making generalizations about "Chinese". And I was disagreeing with your notion that it might be worth talking about "whites" and "blacks" in a conversation about biology. Are you saying there is a ton (or even any) empirical evidence for the generalizations in question about "Chinese", "Whites", and "Blacks"?

No.

I'm saying that there is no reason to think that there aren't average intelligence differences between genetic groups. That's a different thing that knowing what they are, or even caring what they are. But the fact that some people are in denial about the very possibility is interesting, given that it's likely at variance with reality.

You lost me. If you're ideologically determined to be an individualist, what difference does this argument make anyway?

I missed the boat on the response to this.

Robert, my ideological determination isn't the issue. The issue is the ideological determination of those who deny basic human nature, and the differences between individuals.

Of course I'm an individualist. My point is that everyone should be. But I notice that most of the people who deny individuality (i.e., blank slaters, who think that we are formed totally by our environment, and can be thus formed into the superior Soviet man or woman) and adhere to group rights (but not group traits) are also collectivists. They are the heirs of Rousseau. And the later fascists that followed him.

I don't think that this is a coincidence. That is why this is important.

I'm saying that there is no reason to think that there aren't average intelligence differences between genetic groups. That's a different thing that knowing what they are, or even caring what they are. But the fact that some people are in denial about the very possibility is interesting, given that it's likely at variance with reality.

I think people on "the Left" will vigourously oppose the notion that "blacks" could possibly be dumber than "whites" (or vice versa). They might be doing it for ideological reasons, but science backs them up. "Blacks" isn't a unitary genetic group. It includes countless genetic groups, encompassing the majority of humanity's genetic diversity.

I think people on "the Left" will not oppose the idea that intelligence is inheritable and that genetic groups can have intelligence differennces -- they don't really believe the tabla rasa theory - but this only becomes apparent when you make it absolutely clear that when you say "genetic group", you mean "a nuclear family". People on the left, the right, libertarians, and everyone else, will be pretty much united in their agreement when you say something like "wow, Hans Einstein was a really smart guy, he obviously got it from his parents".

If you are saying that the truth is that genetic groups larger than a nuclear family but much much smaller and much better defined than "whites" and "chinese" exist, and that they have differences in their average intelligence, ok, but I bet that the better defined you make the group, the less objection you'll find from "the Left". New findings about the intelligence of Ashkenazi Jews might be a good test case - I wonder if there was any more objection from "the Left" than from "the Right" about that finding... ...or maybe it is a bad test case, because of Jewish history. Can you think of an analogous situation with some other well-defined genetic group? I can't.

I think people on "the Left" will vigourously oppose the notion that "blacks" could possibly be dumber than "whites" (or vice versa).

No doubt, though they'd also doubtless fight much harder against the former proposition than the latter. Do you disagree?

They might be doing it for ideological reasons, but science backs them up.

You can say that if you want, but we still await some evidence for it.

I think people on "the Left" will not oppose the idea that intelligence is inheritable and that genetic groups can have intelligence differences -- they don't really believe the tabla rasa theory

Then you haven't been paying much attention. If it could be shown that you are wrong about this, would you change your opinion?

I would refer you to the writings of Stephen Jay Gould. He was a brilliant biologist and baseball fan, and an unrepentant Marxist who had a large blind spot in this area.

>If it could be shown that you are wrong about this, would you change your opinion?

Yes! Always. That's why I read blogs by people who don't believe what I believe.

I read parts of "The Mismeasure Of Man" by Gould a long time ago. Gould didn't argue that intelligence wasn't inheritable, did he? Are you suggesting that Gould didn't believe that Albert Einstein & Mileva Mari? 's children were likely to be smart, even if taken away at birth and raised by a more normal set of parents?

(This might not be the best example: They had three children -- Hans was quite bright and successful, Eduard was bright but mentally ill, and Lieserl may have been mentally retarded.)

Anyway: we DO have some evidence that blacks are no more or less intelligent than whites! The lack of any coherent definition of "whites" and "blacks" is the first clue! The huge genetic diversity among both groups is the second. The only distinct difference between the two groups is skin color. Everything else is up in the air. Here is an example: Are the Dobe !Kung people black? Are the marsh Arabs of Southern Iraq white? How about the Ainu? Try to figure out who is white when you go to Brazil.
Read this: http://en.wikipedia.org/wiki/Caucasian_race
The whole concept doesn't make any sense. You might as well say we don't have any evidence that unicorns aren't smarter than horses.

Robert, are you denying that close interbreeding populations share genetic traits?

I'm not denying it at all. All interbreeding populations share genetic traits, whether they are close or not. The question is how much genetic diversity exists in the population. Oh, and did you mean "closed" or "close"? If close, how close really matters. "White" isn't close - it doesn't even exist as a meaningful category. My position is that "white" is like "unicorn". "Icelandic" is probably getting closer. (I recall that Jews and Icelanders are often used in genetic studies.) "Hungarian" isn't very close -- quite a bit of genetic diversity, despite the fact that their weird language isolates them a bit from the rest of Europe.

(We need a biologist.)

I'm not denying it at all. All interbreeding populations share genetic traits, whether they are close or not. The question is how much genetic diversity exists in the population.

You're evading the issue.

Are you, or are you not, a blank slater?

That is, do you, or do you not believe that a) all human beings are endowed at birth with the same physical and intellectual potential and b) all genetically-related populations have the same traits? (Note that (b) follows from (a)).

If you don't believe this, you are at variance with the beliefs (even if they haven't explicitly admitted it even to themselves) of many self-styled "progressives."

This is the old Bell Curve argument again. The Left jumped on the Bell Curve as being "racist," and, predictably, the Right responded by thinking they were on to something.

Unfortunately, as offensive as the "racist" slur is, I consider the Bell Curve to be deeply in error. Specifically, I disagree that the very intelligent have a huge natural advantage that ensure that they will do well and leave the less intelligent in the dust. It's not surprising that intelligent people do better in life than less intelligent people, on average, if you consider only income, for the following reasons:

First, intelligent people are far more likely to graduate from college. This enables them to get sinecure jobs afterward in business, not because they are especially good at those jobs, but simply because convention states that Businesses Should Go After College Graduates.

Second, many don't even go into the business world, but instead become academics who get paid very well to prove that the US only won the cold war because it cheated.

Third, a very small proportion of intelligent people really do make it big through some breakthrough and become millionaires or better. Those who do this are almost always on the high end of the Bell Curve. Their huge paychecks throw the average off. Therefore, if a 150 IQ works as a carpenter and barely holds on to his job, he may make $15 per hour less than a 110 IQ who excels as a carpenter. However, the 150 IQ inventor of a high tech device who makes $1000 per hour more than compensates when you consider all high IQ's as a set. This doesn't make the incompetent carpenter any happier as an individual, however.

As you can see, while all these facts tend to drive IQ upward, they make hash of the idea that we're headed for a nation in which natural supergeniuses will rule the world. If anything, many intelligent people are coasting on their overinflated reputations. Undoubtedly the Jesuits at the time of Philip II were smarter than almost any others of their time; but that didn't change the fact that they were a dated group, and that their status would soon take a nosedive.

I definitely do not believe (b). I don't know what "genetically related population" means, but if it means "white" or even "Hungarian", then I don't believe it. Hungarians don't have the same traits. Jews and Icelanders don't have the same traits. Family members don't have the same traits. You probably meant "some of the same traits", but all members of a species have some of the same traits. You need to define your terms better, but you, like everyone else, can't. All you can do is point to particular genes and talk about who inherits them. Focus on genes, and forget about populations.

Nobody believes (a). Every single liberal or leftist or progressive on the planet understands that someone with severe mental retardation will not have the same intellectual potential as a genius. Some people are short, some people are tall; all liberals/leftists/progressives know this too. The only grey area involves average intelligence. And as I've said, here, leftists are happy to grant that cognitive traits can be inherited in families. In the case where a son never knew his father, a liberal/leftist/progressive won't object if you say "he's a chip off the old block!" The Left's politics happens to match the science: that genes matter, and arbitrarily defined populations with extremely high genetic diversity like "whites" are just distracting nonsense.

Ken, I'm not defending The Bell Curve (I never even read it). I'm only defending the notion that it could be true, something that much of the Left is in denial about.

I don't know what "genetically related population" means, but if it means "white" or even "Hungarian", then I don't believe it. Hungarians don't have the same traits. Jews and Icelanders don't have the same traits.

It means a group of people who have interbred with each other, with minimal breeding with outsiders, for a period of time. For example, the !Kung bushmen or the Ibo tribe. The former are on average very short, and the latter are on average tall and lanky and good runners. This is a trait that each group shares, though obviously there are individual exceptions. Both of these groups have much higher melanin content in their skin than, say, Icelanders.

Now if these groups can have so much similarity within themselves, and vary so much with other groups in these physical morphologies, why should we believe that there is no variance between groups in average intelligence level? That is the proposition that Gould attempted to argue in The Mismeasure of Man. The argument failed, because he didn't make it from science or logic, but purely from ideology.

Again, note that I am not claiming that "whites" are smarter than "blacks," on average. I'm simply claiming that it's plausible that that's the case. It's equally plausible that it's the other way around. I have no opinion on the matter either way, and I don't think that it's even a useful bit of information to know, because it doesn't matter what the average is--the only appropriate policy is to deal with people as individuals, not as members of groups. Unfortunately, the Left sees group identity as more important than individual identity.

Actually, those denying a genetic component to intelligence are denying evolution as well. If there is no variation in a trait due to genetics, how could it have evolved? There would be nothing for selection to act on.

Wait a minute - Robert, you honestly believe that the term "black" does not give useful genetic data? When was the last time you saw your heart surgeon? One of the larger factors in heart risk is "Are you black?" Blacks are at far greater risk of heart attack than non-blacks (including whites).

There are others as well - blacks seem to be more susceptible to the aids virus (remember, that's why Rev. Whosit says it is a white conspiracy), whites get skin cancer more easily, blacks look better in suites...

The fact is, there are real differences between the average genetic input of blacks, whites, yellows, oranges, mauve, etc. We need to celebrate that and use it, not sweep it under the carpet and pretend it's not true because it doesn't match our politics!

Using race to judge an individual is wrong. But that doesn't mean that all races are the same. It just means that the standard deviation is large compared to the differences in the mean.

It really does mean that blacks should see their heart doctors earlier and more often than whites, though. Not because blacks should be forced to turn over extra income to doctors, but because they are genetically different, and at higher risk.

The Left's politics happens to match the science: that genes matter, and arbitrarily defined populations with extremely high genetic diversity like "whites" are just distracting nonsense.

Geez, I just noticed this. So you're saying that the left opposes affirmative action? Did you type this with a straight face?

Just as we should remain culturally relativistic we should also become genetically relativistic. Understanding and accepting the fact that people are different and people have a right to be whatever their genes have prescribed them to become.

However, it is appropriate to judge someone based upon their genetics if you do so from a standpoint of genetic neutrality. If there is a trait that is ultimately harmful to a person or group of people in some way then it is morally responsible to try and change or treat that genetic trait. So, one can judge genetic traits as either being right or wrong from a genetically neutral position that decides if a trait hinders an individual's well being in some way.

"Lieserl may have been mentally retarded"

On what data is this based? Lieserl died in infancy. IIRC there is only one reference to her, in a letter from Albert to Mileva Maric: only a single sentence.