Why does IQ cluster around 100 points?

[Speakpigeon]

Or can you explain how Wikipedia is wrong?

Defining the curve has nothing to do with the production of the curve.

The curve is the number of people with a certain score.

With any written test with a random group sufficiently powered you will get a normal distribution of scores.

You can arbitrarily label the mean as 100 and one standard deviation from it as something else, but every normal curve has standard deviations from the mean.

The test does not create a normal curve. The test can change the normal curve a little but it is still a normal curve.

Human intellect produces it.

This is contradicted by Wiki.

Maybe you need more data to understand what Wiki says. Look here, more data:

By this definition, approximately two-thirds of the population scores are between IQ 85 and IQ 115. About 2.5 percent of the population scores above 130, and 2.5 percent below 70.
(...) IQ scales are ordinally scaled. While one standard deviation is 15 points, and two SDs are 30 points, and so on. (...) this fixed standard deviation means that the proportion of the population who have IQs in a particular range is theoretically fixed
https://en.wikipedia.org/wiki/Intelligence_quotient

EB

 

[Speakpigeon]

All measures are relative to a unit. There is therefore no possibility of measuring intelligence in the absolute. The IQ test measures your intelligence by comparison to the rest of the population, and therefore relatively to that of the rest of the population. For a given score, the test is designed so that there will be broadly always a fixed, predefined percentage of the population bellow that score. Somebody with an IQ 130 will always have an IQ higher than that of, broadly, 97.5 percent of the population.

I will guess that the IQ test has to be re-calibrated regularly so that your score can be calculated relative to that of the current population.

However, I don't see why the score of someone today, calculated relative to the population of 1000 years ago for example, wouldn't be significant in itself, provided we had the data and the tests themselves were the exactly same.

Anyone with a view on that?
EB

 

[untermensche]

This is contradicted by Wiki.

Maybe you need more data to understand what Wiki says. Look here, more data:

By this definition, approximately two-thirds of the population scores are between IQ 85 and IQ 115. About 2.5 percent of the population scores above 130, and 2.5 percent below 70.
(...) IQ scales are ordinally scaled. While one standard deviation is 15 points, and two SDs are 30 points, and so on. (...) this fixed standard deviation means that the proportion of the population who have IQs in a particular range is theoretically fixed
https://en.wikipedia.org/wiki/Intelligence_quotient

EB

That does not contradict what I said.

All that says is the peak of the ever present normal curve is arbitrarily labeled as one thing (100) and standard deviations from the peak are arbitrarily labeled something else.

It says absolutely nothing about the production of the curve.

 

[untermensche]

That's an odd way of saying "I was wrong, thanks for educating me".

I agree.

Since nothing close to that has happened.

You have made an empty claim you could not back up.

I quoted a source on how  Raven's Progressive Matrices, a common component of many current IQ test suites, often yield bimodal distributions of raw scores.

I linked a book-sized description of the different techniques that are employed to normalize results, i.e. to get from whatever distribution the raw scores show (including, explicitly so, multimodal ones) to a normal distribution.

The fact that your unable to read and barely able to think is not my problem.

That's not an IQ test.

It's not a verbal test.

And it is a test a person can change their grade greatly with practice.

If there are two peaks (I have not seen any study that produced two peaks from you) that just shows unfamiliarity with the type of test. It shows motivational breakdown. Give people time to gain familiarity and time to practice and you will get a normal distribution.

And your claim about two peaks was about an IQ test.

You have failed to show one shred of evidence to back up your claim.

 

[ronburgundy]

Has the OP question been clarified yet? Obviously the "100 points" is a meaningless and arbitrary product of how it is normalized.
So, it the question:
1) Why is the distribution normal around the mean?
2) Why isn't the mean/median increasing?

If 1, then the answer is that nearly every continuous variable is normally distributed unless there is some artificial constraint on it.

If 2, then the answer is that intelligence IS increasing, and a 100 IQ score today reflects more intelligence than a 100 score in 1960. This isn't b/c of selection, but b/c of exposure to more cognitively stimulating information during early development, nutrition, and likely a reduction in exposure to lead and other toxins.

If anything, selection is working in the opposite direction, such that below average intelligent people are having more kids, which would drive the average down, if not for the general improvement in environmental conditions .
It takes very little intelligence to reproduce. The hard part is surviving to do so and keeping one's offspring alive. But even that has been made quite easy by modern societies where simply doing what you are told ensures survival, and even that isn't required when there are strong safety nets. In this context, one actually has to have the intelligence to avoid reproducing, otherwise it is likely to happen.
And the biggest determinant is desire to reproduce at a higher or lower rate. People more likely to form their own views and shun traditions (such as "life is about kids") or who have more fulfilling careers of their choosing will tend to be less motivated to procreate at a high rate. Having more intellectual ability will tend to increase one's likelihood of not just accepting traditional ideas and give one more career opportunities, and thus disincentivize reproduction. Although, these relationships are weaker than often presumed, with virtually zero IQ difference between those on top of the economic ladder versus those at or just below the median. All of the relationship lies in those at the very bottom of the economic ladder being disproportionately below average IQ, and still about 1/3 of them are above average b/c random misfortune plays a huge role in economic outcomes.

 

[untermensche]

Has the OP question been clarified yet? Obviously the "100 points" is a meaningless and arbitrary product of how it is normalized.
So, it the question:
1) Why is the distribution normal around the mean?
2) Why isn't the mean/median increasing?

If 1, then the answer is that nearly every continuous variable is normally distributed unless there is some artificial constraint on it.

If 2, then the answer is that intelligence IS increasing, and a 100 IQ score today reflects more intelligence than a 100 score in 1960. This isn't b/c of selection, but b/c of exposure to more cognitively stimulating information during early development, nutrition, and likely a reduction in exposure to lead and other toxins.

If anything, selection is working in the opposite direction, such that below average intelligent people are having more kids, which would drive the average down, if not for the general improvement in environmental conditions .
It takes very little intelligence to reproduce. The hard part is surviving to do so and keeping one's offspring alive. But even that has been made quite easy by modern societies where simply doing what you are told ensures survival, and even that isn't required when there are strong safety nets. In this context, one actually has to have the intelligence to avoid reproducing, otherwise it is likely to happen.
And the biggest determinant is desire to reproduce at a higher or lower rate. People more likely to form their own views and shun traditions (such as "life is about kids") or who have more fulfilling careers of their choosing will tend to be less motivated to procreate at a high rate. Having more intellectual ability will tend to increase one's likelihood of not just accepting traditional ideas and give one more career opportunities, and thus disincentivize reproduction. Although, these relationships are weaker than often presumed, with virtually zero IQ difference between those on top of the economic ladder versus those at or just below the median. All of the relationship lies in those at the very bottom of the economic ladder being disproportionately below average IQ, and still about 1/3 of them are above average b/c random misfortune plays a huge role in economic outcomes.

I totally agree that what is happening is more and more of the type of thinking required for the test is being taught and taught earlier because it is being more widely known and understood.

For any type of question there is the familiarity with the type of thinking that is required to answer the question and the speed and accuracy of the thinking.

Early familiarity with the types of thinking required to answer certain questions is better than later familiarity due to the nature of the early memory.

Part of an IQ score is the age in which a person was introduced and understood certain kinds of thinking. Early introduction and comprehension will create better accuracy and speed over the lifetime of most people just like a language acquired early stays with a person their whole life.

 

[steve_bank]

The 60s brought down traditional values. The result was increased STD, drug abuse, tearing part of families, single parent families, and so on.

Was making drugs mains teat an intelligent thing to do?

IQ measures some general capacities related to problem solving. It says nothing about rationality. The Nazis were great problem solvers. The terrorists who figured out how to make IEDs in Iraq using technology were very intelligent.

 

[untermensche]

The 60s brought down traditional values. The result was increased STD, drug abuse, tearing part of families, single parent families, and so on.

Was making drugs mains teat an intelligent thing to do?

IQ measures some general capacities related to problem solving. It says nothing about rationality. The Nazis were great problem solvers. The terrorists who figured out how to make IEDs in Iraq using technology were very intelligent.

Humans are intelligent.

And what one human understands others can understand too if told about it and over time more and more can understand.

 

[Jokodo]

I quoted a source on how  Raven's Progressive Matrices, a common component of many current IQ test suites, often yield bimodal distributions of raw scores.

I linked a book-sized description of the different techniques that are employed to normalize results, i.e. to get from whatever distribution the raw scores show (including, explicitly so, multimodal ones) to a normal distribution.

The fact that your unable to read and barely able to think is not my problem.

That's not an IQ test.

How could you tell? you don't know what an IQ test is!

It's not a verbal test.

So?

And it is a test a person can change their grade greatly with practice.

What if?

If there are two peaks (I have not seen any study that produced two peaks from you) that just shows unfamiliarity with the type of test. It shows motivational breakdown. Give people time to gain familiarity and time to practice and you will get a normal distribution.

And your claim about two peaks was about an IQ test.

Since you have no demonstrable understanding of what an IQ test is, this is a meaningless statement coming from you.

You have failed to show one shred of evidence to back up your claim.

You wouldn't even recognise evidence if it were gnawing at your nose.

 

[untermensche]

Evidence is a study that produced two peaks by manipulating questions on an IQ test.

Evidence is not an empty claim it is possible.

 

[steve_bank]

The 60s brought down traditional values. The result was increased STD, drug abuse, tearing part of families, single parent families, and so on.

Was making drugs mains teat an intelligent thing to do?

IQ measures some general capacities related to problem solving. It says nothing about rationality. The Nazis were great problem solvers. The terrorists who figured out how to make IEDs in Iraq using technology were very intelligent.

Humans are intelligent.

And what one human understands others can understand too if told about it and over time more and more can understand.

So are chimps and squirrels.

IQ addresses a narrow segment of what we call intelligence. IQ attempts to quantify numerically a relative comparison among humans.

Does the diffence between 125 and 115 on a standard test mean anything in terms of ability to achieve a goal?If you take a test that says you have an IQ of say 135 does that mean you are actually more intelligent in the world than someone at 100? Do you have an intelligent reasoned responses?

IQ is a limited but useful tool.

 

[untermensche]

Does the diffence between 125 and 115 on a standard test mean anything in terms of ability to achieve a goal?

Depends on the goal.

More importantly does a higher score mean you can get along with others better? Does it mean you have more energy?

Does it mean you are more creative?

Does it mean are a better teacher? Does it mean you are a better leader?

It just means you are a better test taker.

If you take a test that says you have an IQ of say 135 does that mean you are actually more intelligent in the world than someone at 100?

It means you have more mental problem solving skills.

But in the real world the person with a 100 IQ score might be a much better leader and dominate.

Do you have an intelligent reasoned responses?

That's what I always have.

 

[rousseau]

The 60s brought down traditional values. The result was increased STD, drug abuse, tearing part of families, single parent families, and so on.

Was making drugs mains teat an intelligent thing to do?

IQ measures some general capacities related to problem solving. It says nothing about rationality. The Nazis were great problem solvers. The terrorists who figured out how to make IEDs in Iraq using technology were very intelligent.

Well, there's two issues there, and one of them might strike at the core of this thread.

The first is that IQ doesn't necessarily imply rationality because the brunt of the curve is inherently not very rational, or even interested in being rational, or even aware that rationality is some kind of end goal. Those who have rationalized their life and experience and developed their own principles to live by are an exceedingly small portion of any group of people.

The other thing is that there is a distinction between problem solving ability and experience. For example, I'm a pretty smart guy, but any wisdom I do have comes from significant post-secondary education, wealth to self study, and so on. What my IQ measures is my propensity to be able to make deductions and learn from these experiences, rather than just bouncing around trying to survive.

So to say that IQ doesn't imply anything about rationality, that may be true, but I don't see why that's any type of indictment of it. It's just that in practice people's real problem solving ability is so low that it's more secondary to how we achieve reproduction/survival.

Maybe it's that most of us are more oriented toward action than reflection. We're people who don't think, we just do, which more often than not results in kids.

 

[Loren Pechtel]

Nope. It's been a long-standing problem in teaching programming--some people get it, some don't. The result is grades in the early classes tend to produce a double-humped curve--the lower hump from those who don't get it, the upper hump from those who do. There are no magical questions that the dumb ones get right.

There is a normal distribution among those who get it and those who don't.

There are not two separate groups.

You get a normal distribution amongst those who get it and a normal distribution amongst those who don't, when you add them together (say, the scores from a programming 101 class) you get a double-humped curve.

I've seen something similar, albeit without grades, when I was a lab assistant in a computer room hosting a computer literacy for seniors class. Some got the concept of a control key, some were apparently incapable of understanding. (And note that I never saw anyone change groups. Either they got it or they didn't, no amount of explaining by the teacher or I could get them to understand.) They either understood and had minor problems, or they didn't understand and had major problems, there was no middle ground.

Except that intelligence is how you answer a question or find a solution.

Looking at end results tells you absolutely nothing about intelligence.

You're assuming a problem has a single correct solution. In the real world that is often not the case.

No I'm not.

I'm assuming there is more than one way to skin a cat.

And the way you skin the cat is intelligence not a skinned cat.

But you're saying people have to skin the cat in the "right" way. I'm saying intelligence is the ability to find ways to skin the cat, it doesn't matter which path you take as the result is always a skinned cat.

- - - Updated - - -

Why do human heights cluster about a mean?

https://www.bing.com/images/search?...orm=IEQNAI&selectedindex=0&exph=0&expw=0&vt=0

A bell or Gaussian empirical curve be it IQ or physical characteristic infers a random variable. Randomness somewhere in the process.

Disagree--a bell curve infers multiple random variables. A single random variable gives all outcomes of equal probability.

Random combinations of environment growing up, education, parenting, and genetics. Random in the semse of Gausian means uncorrelated variables. Genetics and parenting are uncorrelated random variables.

Height is affected by both genetics and nutrition while young. North Koreans are stunted. Nutrition and genetics are uncorrelated random variables affecting height.

And that's supposed to be a rebuttal how?

 

[untermensche]

You get a normal distribution amongst those who get it and a normal distribution amongst those who don't, when you add them together (say, the scores from a programming 101 class) you get a double-humped curve.

No.

There is a mean. A score most people get.

Then to the right of the mean are less and less people who get it. And to the left are less and less who do not get it.

One hump. A normal curve.

I'm assuming there is more than one way to skin a cat.

And the way you skin the cat is intelligence not a skinned cat.

But you're saying people have to skin the cat in the "right" way. I'm saying intelligence is the ability to find ways to skin the cat, it doesn't matter which path you take as the result is always a skinned cat.

I'm saying the intelligence is how you skin the cat not simply the fact the cat was skinned.

One way of skinning may be more useful for skinning a squirrel so that may be a better way to learn how to skin it.

 

[steve_bank]

The 60s brought down traditional values. The result was increased STD, drug abuse, tearing part of families, single parent families, and so on.

Was making drugs mains teat an intelligent thing to do?

IQ measures some general capacities related to problem solving. It says nothing about rationality. The Nazis were great problem solvers. The terrorists who figured out how to make IEDs in Iraq using technology were very intelligent.

Well, there's two issues there, and one of them might strike at the core of this thread.

The first is that IQ doesn't necessarily imply rationality because the brunt of the curve is inherently not very rational, or even interested in being rational, or even aware that rationality is some kind of end goal. Those who have rationalized their life and experience and developed their own principles to live by are an exceedingly small portion of any group of people.

The other thing is that there is a distinction between problem solving ability and experience. For example, I'm a pretty smart guy, but any wisdom I do have comes from significant post-secondary education, wealth to self study, and so on. What my IQ measures is my propensity to be able to make deductions and learn from these experiences, rather than just bouncing around trying to survive.

So to say that IQ doesn't imply anything about rationality, that may be true, but I don't see why that's any type of indictment of it. It's just that in practice people's real problem solving ability is so low that it's more secondary to how we achieve reproduction/survival.

Maybe it's that most of us are more oriented toward action than reflection. We're people who don't think, we just do, which more often than not results in kids.

Ok, but my point is IQ only relates to a narrow scope. Being good at objective problem solving like software or electronics design does not infer generalized problem solving, like our current political crisis. If we were all that intelligent we would not be in the mess we are in. A lot of people in Congress are high IQ types who went to top tier schools.

As for being smart I always looked to others around me to get a sense of where I stood. I would not usually refer to myself as smart. Too easy to get carried away with yourself.

 

[Jokodo]

Back to OP to sidestep this fruitless discussion with the impersonation of dunning-kruger:

I've been running through some ideas lately about why the IQ of most populations clusters around 100.

It clusters around 100 per definition.

It seems strange to me that if intelligence, reason, and problem solving skill are generally considered positive traits, why the population doesn't drift to the right.

It does, quite substantially.

Instead it seems like there is some kind of reproductive advantage of not being too smart.

Or maybe, the additional benefit of being smarter is insufficient to outweigh the regression to the mean? Maybe mutations that make you less smart are simply more likely to occur than mutations that make you smarter, and at some point selection becomes inefficient to weed them out?

But to take it a bit further I've been asking myself: well, what is a person like that's not too smart? Some thoughts:

- They're more likely to take social norms for granted
- They're less likely to question ideologies that act as social bonds

Are you saying that small-time criminals tend to be smarter than law-abiding citizens? Also, social norms can be quite complex. Understanding them (and knowing when they can be safely ignored) is a science of its own.

- They may be worse at family planning so reproduce more at the expense of their future

Or they may be better at accepting the societal consensus that vaccines are a good thing, as per your above suggestions that they take social norms and ideologies for granted. I don't have any statistics 1t hand for North America, but in Germany it can be shown that the "proles" have the highest vaccination rates, while most vaccine refusers are actually academics (from unrelated fields) with a strong Dunning-Kruger.

- High IQ might come at the expense of EQ, which is more critical to forming relationships

Highly doubtful. There's reason to believe that the complexity of social relations is the main driver of intelligence in primates. There's in fact a solid correlation between neocortex size (or was it encephalization quotient? - writing from memory here) and group size in primates, suggesting that the need to uderstand, participate in, and manipulate social relations in large groups was the/a main driver in primate brain evolution, more than foraging strategies or habitat. The guy most famous for popularizing this notion is a certain Dunbar, you can google his works.

High IQ might however come at the expense of any other useful trait, e.g. the ability to digest starch, resilience against inflammations of the skin, or an immune system that doesn't misfire and wantonly attack your own cells. One and the same gene can have multiple, unrelated effects, and those are under no obligation to fall into the same domain to a casual human onlooker.

It's an interesting point to consider because it suggests that, in some ways, intelligence can be maladaptive. So it's possible that all of the issues we see with people and strange beliefs is a feature, not a bug, of our species.

Your thoughts?

Depends on what you mean with strange beliefs. If you mean a proclivity to impute reasons where none are to be found, it very likely is indeed a feature, not a bug. That comes with the relative cost of false positives vs. false negatives: Jump at a cracking branch, and nothing much is lost. Fail to jump at an approaching leopard, and you may never have to think about cracking branches again.

 

[untermensche]

Back to OP to sidestep this fruitless discussion with the impersonation of dunning-kruger:

You mean like somebody who thinks the normal distribution is artificially created?

When all tests produce a normal distribution when sufficiently powered.

 

[Speakpigeon]

If anything, selection is working in the opposite direction, such that below average intelligent people are having more kids, which would drive the average down, if not for the general improvement in environmental conditions .
It takes very little intelligence to reproduce. The hard part is surviving to do so and keeping one's offspring alive. But even that has been made quite easy by modern societies where simply doing what you are told ensures survival, and even that isn't required when there are strong safety nets. In this context, one actually has to have the intelligence to avoid reproducing, otherwise it is likely to happen.
And the biggest determinant is desire to reproduce at a higher or lower rate. People more likely to form their own views and shun traditions (such as "life is about kids") or who have more fulfilling careers of their choosing will tend to be less motivated to procreate at a high rate. Having more intellectual ability will tend to increase one's likelihood of not just accepting traditional ideas and give one more career opportunities, and thus disincentivize reproduction. Although, these relationships are weaker than often presumed, with virtually zero IQ difference between those on top of the economic ladder versus those at or just below the median. All of the relationship lies in those at the very bottom of the economic ladder being disproportionately below average IQ, and still about 1/3 of them are above average b/c random misfortune plays a huge role in economic outcomes.

I think there's no good reason to assume intelligent people will on average favour eschewing reproduction in favour of other activities in life.

I think myself the two things are essentially unconnected.

What people want is determined by their brain through unconscious processes and is perhaps essentially a matter of their emotional state, most plausibly not of their intelligence.

Your intelligence only affect how you go about doing what you want to do or achieve.
EB

 

[Speakpigeon]

You have failed to show one shred of evidence to back up your claim.

You wouldn't even recognise evidence if it were gnawing at your nose.

Well, absence of evidence is evidence of absence.

Still, there is good evidence and UM either doesn't want to consider it, or doesn't understand it, or can't think straight about it or at all, and is not even trying to offer a coherent point of view.

Others have tried and tested. It just doesn't work.
EB