Why does IQ cluster around 100 points?

[untermensche]

Saying what you will get is one thing.

Actually seeing what you get is another.

Making claims is one thing.

Providing an example where it has actually happened is another.

Are you going on record claiming that I can ask a random crowd (ie not specifically GoT fans) a Quiz focussed on GoT and still get a unimodal normal distribution?

Willing to bet this time?

You will get a normal distribution of knowledge.

Some will know more than others.

Some will guess better than others.

But the test has to be complex enough so that the few with the best knowledge can be found.

 

[Jokodo]

Saying what you will get is one thing.

Actually seeing what you get is another.

Making claims is one thing.

Providing an example where it has actually happened is another.

Are you going on record claiming that I can ask a random crowd (ie not specifically GoT fans) a Quiz focussed on GoT and still get a unimodal normal distribution?

Willing to bet this time?

You will get a normal distribution of knowledge.

Some will know more than others.

Some will guess better than others.

But the test has to be complex enough so that the few with the best knowledge can be found.

...an some are, apparently, unable to answer a simple yes/no question with "yes" or "no"...

 

[untermensche]

You will get a normal distribution of knowledge.

Some will know more than others.

Some will guess better than others.

But the test has to be complex enough so that the few with the best knowledge can be found.

...an some are, apparently, unable to answer a simple yes/no question with "yes" or "no"...

Run the study. I'm not stopping you.

But science is full of people who said one thing before the study and another after.

Why can't you show me one published study?

Nobody is deliberately trying to create a normal distribution with an IQ test.

All they are trying to get is separation of abilities and by doing that a normal distribution comes out.

 

[ronburgundy]

If you create a random trivia test heavily loaded with Game of Thrones/Baseball questions, you'll get a bimodal distribution.

Correct, b/c you are measuring two qualitatively distinct populations, people who watch GoT or baseball and people who do not. Each population is normally distributed, but different populations are not distributed under the same normal curve.

Because the answers are intercorrelated.

The answers on an IQ test are also intercorrelated and yet you get a unimodel normal distribution.

You'll only get a bi-model distribution in your hypothetical context because you are measuring distinct populations which are normally distributed around different means. The two populations must rely upon qualitatively distinct skills and and causal factors to get the questions correct. Both groups can use various general knowledge, reasoning skills, and random guessing to get a correct answer, but only the group that actually watches the show can rely upon memory of what they watched. This added factor basically adds a constant to all their scores creating a higher mean around which the watchers of the show vary.

 

[Jokodo]

You will get a normal distribution of knowledge.

Some will know more than others.

Some will guess better than others.

But the test has to be complex enough so that the few with the best knowledge can be found.

...an some are, apparently, unable to answer a simple yes/no question with "yes" or "no"...

Run the study. I'm not stopping you.

But science is full of people who said one thing before the study and another after.

Why can't you show me one published study?

Can you show me a published study saying the Sky is Blue?

 

[untermensche]

Run the study. I'm not stopping you.

But science is full of people who said one thing before the study and another after.

Why can't you show me one published study?

Can you show me a published study saying the Sky is Blue?

Nice dodge.

The sky is not blue by the way.

The brain's representation of the sky in the mind is blue but the sky has no color. Color is not a feature of objects in the world. It is a feature of minds.

 

[untermensche]

I just ran the study.

Here's my results.

 

[Loren Pechtel]

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.

Saying this doesn't make it so. Nothing says anybody has to get the mean. In a normal bell curve it's the most common result but it doesn't have to be. Consider that computer literacy for seniors class I mentioned--had there been a test I don't think there would have been anyone at the mean as it would have fallen between the clueless and the ones who got it. You'll see this same pattern any time you have a sample composed of those from two radically different abilities.

Lets take an obviously contrived example to illustrate.

You have 1000 people, you administer short IQ test and use the results to give a more detailed IQ test suited to their intelligence. (This can have merit as it avoids having to clutter the test with questions people will find too easy or hard.) Unfortunately, some bureaucrat wasn't thinking and used this preliminary test to divide the people up into "average" (within 1 standard deviation) (~680 people) and not average (~320 people). The second group is going to show a double-humped curve on any IQ test you give them.

 

[steve_bank]

It is a probability distribution that results from a sample population. Researchers run tests and plot the data as a histogram or plot a cumulative distribution. Perform goodness of fit tests.

Ignoring demographics and other group variables what the normal distribution means if you randomly pick people passing by on the street IQs will be randomly distributed with a mean and standard deviation IAW the sample test population.

It means that the arithmetic mean of your random street sample will be around 100.

Statistics 101. Run controlled tests on a sample population, fit a probability distribution to the data, and use it to predict what the result of sampling will be in the general population. Predicting how the variable is distributed in the entire population. That's all there is too it. Empirical statistics.

The fact that the variable is IQ is irrelevant.

 

[untermensche]

Nothing says anybody has to get the mean. In a normal bell curve it's the most common result but it doesn't have to be. Consider that computer literacy for seniors class I mentioned--had there been a test I don't think there would have been anyone at the mean as it would have fallen between the clueless and the ones who got it.

Of course you would.

You would have the people who are really clueless. Then a little more who are a little less clueless.

You will get a peak where people are midway between clueless and not clueless.

Then you would get get less and less people who are less and less clueless until you have a few who were the least clueless.

 

[rousseau]

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

You are not reading carefully. I didn't say that intelligence has a direct impact on choosing to reproduce. It likely to have an indirect effect on reproductive rates by impacting whether you make decision errors that lead to accidentally getting pregnant without intending to, or by its indirect relation to emotional goals. For example, less intelligent people are more likely to find it too taxing and difficult to reason their way to their own conclusions about most things. Thus, they are more likely to defer to authority, tradition, or social norms to decide what they should do. Since the tradition and social norm is that life is about having kids, people that don't deeply and critically question norms (which takes a lot of mental investment) are more likely to adopt this goal that their life is about having kids and thus will have more kids. Also, there is good evidence that strong religious adherence is correlated with lower intelligence. Religious people are less likely to get abortions, so when accidental pregnancies do occur religious people (and thus on average less intelligent people) are more likely to carry it to term.

In addition, all choices are determined by one's options. The more options one has, the less likely they are to pick any one of the options. If you can find enjoyment and happiness from an engaging career of your choosing or from travel and other activities that often require some wealth, then you are less likely to choose the option of having more kids. A person with low intellect has far fewer career options and often no options that are very satisfying, and they are less likely to have the wealth needed to choose travel and forms of consumption that those with means sometimes choose over having kids.

The relation between career options, wealth, and intelligence are not and don't need to be very strong in order for them to have a small but still reliable impact on the reproductive rates of people with higher and lower intelligence.

Related to all this is one's ability to exercise self-control and delay their gratification in favor of more long term goals. Kids often interfere with long term goals that many people have. At the same time, kids themselves can be immediately gratifying, plus the sex that accidentally leads to kids is immediately gratifying. General intelligence and IQ are correlated with impulse control and making decisions that optimize delayed gratification, and have associations with the same brain regions. Thus, even when low and high intelligent people share the same goals of trying to balance gratification from sex, kids, and more long term goals, the more intelligent people will tend to be better able to control their actions to achieve the desired balance and thus not have unwanted kids, kids too young, or too many kids that undermine long term goals.

This is along the lines of the argument I read in The Intelligent Paradox, where the author argues that higher IQ is generally predictive of people shirking most social norms.

The part of this that's really interesting to me (and really was the purpose of making the thread) is that if there is something like an 'intelligence sweet spot', where people are intelligent enough to have more kids, but not so intelligent that it becomes maladaptive, then this implies that illogical and delusional belief systems are.. a) a result of this sweet spot, and b) an inherent feature of our species.

So collective knowledge might kill stuff like religion, but it can't kill illogical types of thinking.

 

[rousseau]

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?

Possible, but all it would take is for people within a certain range to reproduce more often, which the evidence seems to suggest is the case.

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.

I'm saying that at some point intelligence often leads to people no longer seeing the world as intrinsically meaningful, whereas people with less intelligence view things like marriage, children, relative wealth, and so on as ipso facto reality and a critical part of a normal life.

The person of lesser intelligence cries at her wedding, the person with more intelligence throws a good party but knows it's just an arbitrary social custom. This means that those with less intelligence are more likely to define their life goals by social custom (e.g. having kids).

The problem is that as intelligence decreases eventually a person becomes incapable of finding a partner or raising a child.

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.

Maybe, but we'd have to see far more data about this before it would suggest anything. Whereas things like family planning are more within the realm of something that would actually explain this. Sure I don't have data either, but I'm just spitballing.

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.

To me that sounds like evidence that re-iterates the point. We've evolved to be social, and prestige is ultimately tied to social prowess, rather than pure problem solving ability. Granted my point is probably way too simplistic, but I think this does bring to bear that social intelligence is typically more critical to survival than intelligence. Mostly, people need enough intelligence to get by.

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.

I actually drew the same conclusion about this thread a few days ago. I wonder to what extent this issue comes down to that. Being paranoid and reactive has more advantages than sitting there thinking too much. The dumb person will bounce around having kids, and in the end everything will somehow work out anyway.

 

[steve_bank]

In the 80s Wayne Green who founded Byte Magazine wrote an oped after speaking to a MENSA chapter.

He called a big bunch of underachievers.

Does having an average IQ mean you can not achieve what a higher IQ person can? I doubt it. For me motivation id far more important than IQ.

 

[steve_bank]

Intelligence leads to a genius p9litician like Hitler doing great harm, to nuclear weapons, to mass technology threatening climate.

There is no one comprehensive Gestalt.

 

[rousseau]

In the 80s Wayne Green who founded Byte Magazine wrote an oped after speaking to a MENSA chapter.

He called a big bunch of underachievers.

Does having an average IQ mean you can not achieve what a higher IQ person can? I doubt it. For me motivation id far more important than IQ.

Depends on what you're trying to achieve.

In my programming diploma motivation wasn't enough, some people's brains just didn't work that way. Actually, the program has the highest drop out rate in the entire college. We started with 200, finished with about 60, and of those 60 only 10 had honours. That's a pretty clear example of a high IQ being a requisite for success.

 

[rousseau]

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.

Yebbut I think you have your definitions crossed: IQ does infer generalized problem solving, but the shape of the curve and the characteristics of people at certain points on the curve imply that most of us aren't good at generalized problem solving. Which was the point of the thread.

I'd go further and argue that most politicians reach that status because of things other than IQ, which is why they're usually meddling at generalized problem solving - they have a solid IQ but not a systems level IQ. That and the incentives to actually make good decisions aren't always there.

My experience says otherwise. The stereotypical engineer in my generation who was good at invention and problem solving objective problems were typical lousily at mangement and organization problems. Not entirly true and not entirely false.

On the other hand there are gifted mangers who are high IQ coming out of business schools who are inept at technical problems. Some people have a gift for logistics. An operations guy I worked with before computer manufacturing systems kept track of the status of thousands of parts in his head.

People who cam mentally keep track of complex schedules in their heads. A program manager I knew told me she visualized schedules as intersecting surfaces and cuvees.

I think what I'm implying is that basically no one has it all figured out. People can be very, very smart, but almost no one gets to the level where they have something like a complete understanding of themselves and the world around them.

So doing stuff that's irrational is normal. By definition there is only about 1 genius out of every 1000 people.

Most of us are smart enough to get by, maybe even very successfully so, but very, very few of us in history have understood much outside of the small scope of our own lives.

 

[steve_bank]

My experience says otherwise. The stereotypical engineer in my generation who was good at invention and problem solving objective problems were typical lousily at mangement and organization problems. Not entirly true and not entirely false.

On the other hand there are gifted mangers who are high IQ coming out of business schools who are inept at technical problems. Some people have a gift for logistics. An operations guy I worked with before computer manufacturing systems kept track of the status of thousands of parts in his head.

People who cam mentally keep track of complex schedules in their heads. A program manager I knew told me she visualized schedules as intersecting surfaces and cuvees.

I think what I'm implying is that basically no one has it all figured out. People can be very, very smart, but almost no one gets to the level where they have something like a complete understanding of themselves and the world around them.

So doing stuff that's irrational is normal. By definition there is only about 1 genius out of every 1000 people.

Most of us are smart enough to get by, maybe even very successfully so, but very, very few of us in history have understood much outside of the small scope of our own lives.

I pretty much agree. That is why it is important to have a few peers you can trust. That is were you get a sense of stability from. Nobody has everything figured out all the time. People who try to appear that way are usually bogus.

 

[Jokodo]

Possible, but all it would take is for people within a certain range to reproduce more often, which the evidence seems to suggest is the case.

I'm not sure the evidence suggests such a thing. Not in any straightforward way, at least. In industrialized societies of the 20th/21st century, people with significantly above average IQ tend to have fewer kids? I buy that. But that does not in any meaningful way imply that their intelligence causes them to have fewer kids. In fact there appear to be studies indicating that this correlation is largely, if not entirely, mediated by career choices: While it is true that college professors and MDs tend to have a higher IQ than janitors, and that janitors tend to have more children than college professors or MDs, I seem to remember studies showing that, within each occupational group, there appears to be little or no correlation between IQ and fertility. Given that up to little more than a century ago, 95%+ of the population, whatever their IQs, were peasants and labourers, thus occupational effects essentially played no role, this is unlikely to be an evolutionarily meaningful observation. It could explain a downward trend or stagnation of intelligence throughout the 20th/21st century if this were what we observe. Ironically enough, the opposite is observed.

I'm saying that at some point intelligence often leads to people no longer seeing the world as intrinsically meaningful,

You seem to be confusing rationality with intelligence defined as problem solving skill. IQ tests don't measure rationality. While there may be some correlation between scoring high on IQ tests and shunning superstitions, the very makeup of the tests itself if anything encourages treating the world as intrinsically meaningful, inferring meaning in meaningless patterns. There is no objective sense in which "8" is the logical continuation of the series "1-2-4" - this could equally be a series where each step between two subsequent numbers is one larger than the last step (leading to "7" as the next number), or any of infinite number of 6th degree binomial functions, or what have you. The rational answer to that kind of question in an IQ test would thus be "insufficient data", but that's clearly not the one they want you to put down.

whereas people with less intelligence view things like marriage, children, relative wealth, and so on as ipso facto reality and a critical part of a normal life.

The person of lesser intelligence cries at her wedding, the person with more intelligence throws a good party but knows it's just an arbitrary social custom. This means that those with less intelligence are more likely to define their life goals by social custom (e.g. having kids).

Says you...

The problem is that as intelligence decreases eventually a person becomes incapable of finding a partner or raising a child.

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.

Maybe, but we'd have to see far more data about this before it would suggest anything. Whereas things like family planning are more within the realm of something that would actually explain this. Sure I don't have data either, but I'm just spitballing.

That much has been obvious from the beginning. (So am I by the way in the preceding paragraph, except I'm not actually pretending this is a serious suggestion.)

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.

To me that sounds like evidence that re-iterates the point.

Wha'?

Allow me to rephrase:

You: "Couldn't it be that high IQ people are too socially inept to succeed?"
Me: "If anything, the evidence suggests that high IQ is positively correlated to social intelligence."*
You: "But that's just what I'm saying!"


*To be fair, the correlation, it seems, can only be inferred up to an IQ range of around 120-130. Beyond that, the data is too sparse to make any meaningful conclusions, though some studies suggests that some kind of bifurcation happens, with a bimodal distribution of low and high social competence among extremely high IQ individuals. Also, I seem to have brought that up in a different post.

 

[Jokodo]

Because the answers are intercorrelated.

The answers on an IQ test are also intercorrelated and yet you get a unimodel normal distribution.

I don't disagree with your main point that a normal distribution is what you'd expect anyway, but you can't infer that intelligence is normally distributed from the distribution of IQ scores. If we had an absolute measure of intelligence, which we don't, it could have a bimodal distribution, or a heavily skewed distribution, or one with a long plateau of essentially uniform frequency - IQ scores would still be normally distributed because the tests are specifically designed to make that happen.

Incidentally @rousseau: a normal distribution at any one point in time is also what you'd expect if intelligence was currently undergoing heavy selection in one direction, so the shape of the curve, even if IQ values were absolute, does nothing to infer that the population is at or near any kind of "sweet spot".

 

[Jokodo]

Why are people with an average IQ not great at solving complex problems, and why is this true for a majority of people?

The flippant answer I gave earlier: because we wouldn't call those problems "complex" otherwise.

On a more serious note, though: people with an average IQ are great at solving complex problems. The problems posed in an IQ test aren't actually particularly complex in any objective sense. They're chosen because they are difficult to humans for whatever reasons. I suspect either of us could build a software that scores in the area of 120-125 on an IQ test (with a specified question format but unknown content) using only open source libraries to build upon, if our employers gave us a couple man-months to work on it. People have built software that scores in the area of 150, and the difficult part wasn't to generate answers, but to identify the answer the human probably meant. That was in 2012

Meanwhile, people with average to very moderate IQ scores routinely recognise friends they last saw ten years ago before they grew a beard, more often than not avoid stepping into dog-poo on the pavement without even properly looking down (and without too much silly dancing around half-decomposed leaves), realise whether an email requires an answer or not, and note when to drop of a conversation because the other person would rather be left alone. All of these are complex problems that are, at the best of times, at the cutting edge of IT research in 2019, and often enough still out of reach.

So if you want a meaningful discussion, you should be asking "why are people poor at task XYZ", not "why are people stupid"?