Humans getting dumber, scientists warn

One of my favorite topics, nothing really new here. The chart out to 2110 is entertaining though, hadn’t seen that before.

“Some believe the Flynn effect has masked a decline in the genetic basis for intelligence, so that while more people have been reaching their full potential, that potential itself has been declining.”

Yeah, their half-joking forecast isn’t so funny anymore. Thankfully I won’t be around in 2110!

If humans are getting dumber and the scientists that conducted this study are humans, then isn’t there a good chance they are so stupid they messed up the results?

judging by the maturity on AF these days, i’d totally agree


Girl in black is pretty good.

I feel like this is the start of a long line of inquiry. What trends increased from the 30s to the 80s and then reversed since then? Smoking is one of the few I can figure. Maybe something with computers or cable tv. Lead is another, but there’s pretty clear evidence that lead to bad for brain development. You’d have to look cross-sectionally by country. Was the decline stronger in different countries? What differences could explain that.

Is it possible that I was born to the smartest generation that will ever live? Typical milennial attitude.

Wow that’s not good. I believe an IQ of 70 is the threshold for mental retardation. At this rate, we may see that in my lifetime. Hopefully those people all start buying stocks.

maybe the IQ test got harder over the years?

So it’s saying that (assuming the proposed theory is correct) that “more people are reaching their potential, but that the potential might be diminishing over time.” That would seem to suggest that society’s members are smarter on average, because more people are getting educated about more things, but that the positive outliers aren’t as outlying.

There are so many possible interpretations of this data point, and that also assumes that the data was collected in a rigorous way, which is not always the case with headline-splashing kinds of research results, where the reporter and the editor has a strong incentive to misinterpret results in a way that generates clicks.

It would be interesting to compare the mean and the median intelligence, and see how those have evolved over time. It may also be that the kinds of things that the intelligence test measures are no longer the kinds of things that our intelligence needs to master (i.e. shapes turning in space, etc.). If Google answers every question we need, perhaps it’s a different kind of thing we need to master.

A parallel might be eyesight. My guess is that human beings on average have poorer eyesight now than at any point in history. But does it really matter? We wear glasses or contacts instead. Sure, if technology suddenly disappeared lots of us would be screwed because of our bad eyesight, but my guess is we’d be screwed on many other accounts too.

Then there’s the question about where the data comes from. Who gets tested for IQ and what populations do they represent. I had thought that probably early IQ tests would have measured people likely to have high IQs, since they cost money, and you don’t spend money to test classes of people who you don’t think are worth a lot. However, the article does say it measures military entrance exams, which arguably will capture a larger cross section of society.

At the same time, one should ask whether the composition of military recruits has changed over time, and the answer to that is almost certainly yes: WWII had a large cross section of society recruited into the military (at least the men), professors and construction workers, white and black, etc… Even the Vietnam war had a fairly broad cross section, such that middle class students had to run to Canada if they wanted to dodge the draft, or GW Bush had to get his politically connected father to transfer him to the Air National guard. The military these days tends to select (albeit not exclusively) from less privileged segments of society. It may even offer those people decent training and better exit options when they are done, but the people going in tend to have fewer attractive offers elsewhere, and so it is not too surprising if the average enlisted IQ result is less than it was during WWII or Vietnam.

And maybe we only need human beings to be “intelligent enough” to accomplish daily tasks. It may be that only 1/4% of the population are now geniuses, whereas half a century ago, 1% were. But if the population has moved from 2 billion to 8 billion, that means that we have - in absolute terms - the same number of geniuses wandering around. Perhaps our social reward systems can’t handle larger numbers of geniuses. After all, no matter how populous the world is, there are still only 400 slots in the Forbes 400. There’s still only room for one POTUS. The systems that are tuned to look for geniuses and place them in locations where their intelligence can be used can presumably expand somewhat, but they probably cannot expand in proportion to population growth (admittedly, Europe’s population is shrinking, but there is still plenty of immigration, and the US is still growing).

When you can source intelligence anywhere in the world, the US, BRICs, etc., why do you need to have so many intelligent people in developed countries. In fact, what is the benifit to being a genius, unless you get your own joy out of being smarter than others (and plenty of dumb people are perfectly capable of convincing themselves that they are smarter than everyone else anyway). We are now in a world where intelligence is almost commoditized, and so what’s the point of developing great intelligence if that intelligence is not rewarded as much as having family wealth, or being physically beautiful, or a celebrity, etc… When being intelligent itself is often a baisis for others to mock you.

In fact, perhaps society doesn’t really want people that are excessively intelligent. There is so much misinformation and logical fallacy running around that it’s now confusing what it even means to be intelligent anymore. Teachers being asked to teach creationism as science? How can people understand the scientific method with something like that. Belief substituting for logic? Perhaps our structures don’t want people to be more intelligent, because then things like examining the evidence for climate change or the effects of enormous concentrations of wealth actually have to be considered. As wealth becomes concentrated, it often helps to have the vast mass of people unable to construct a logical argument.

So yeah. The basic premise seems to be: the vast majority of people have more exposure to education than every before, but there seem to be fewer top intelligences.

^ I glanced at this wall of text and thought “Nope, not reading that”. Guess i’m part of the dumb population.

No worries. Anyway, gravity is just a theory.

I thought of another potential cause of the recent decline. Children with low birth weight typically have lower average intelligence later in life. Medical advances have increased the number of children born with low birth weight (who previously died).

Not sure if the effect is significant enough to explain the whole decline, but it would be something worth investigating. If it is a significant factor, then I wonder what the evolutionary consequences are.

I didn’t read the article, but I believe more and more intelligent people are reproducing together and more and more dumb people are reproducing together. So we’ll see less people with average intelligence in the future.

“Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.” Albert Einstein

BChad, I like your posts but you’ve made this a bit more messy than it needs to be. I’ve done some work in this field, and it’s actually pretty straight forward. All the observations point to the same thing (decreasing genetic intelligence, mean, not std dev).

Seen thru the lens of evolution it makes more sense. Homo is a product of the pleistocene (the last ice age). Around 2.5M years ago the ice age begins, and we see tool use and meat scavenging begin, as the fruit/plants retreat. Tool use, meat consumption, and cranial capacity grow thru time, peaking in the Upper Paleolithic around 30K years ago. Then the climate changes (ice age ends) large herbivores start dying off, and by 10K YA sapiens 1) form towns and 2) switch to grains. At this point, for the first time in homo history, cranial capacity starts to decrease! It has decreased around 10% since, and the correlation between cranial capacity and IQ is around .4. The industrial revolution may have triggered another decline. Why? There are multiple reasons why the Neolithic and Industrial revolutions likely resulted in genetically stupider people. First, as already covered homo evolved their brain on meat/fish, and when you remove those building blocks, it is difficult to hold onto that cranial capacity. Second, with specialization (which begins in the Neolithic) there is NO NEED for the masses to hold onto intelligence; the average person can float thru life making babies, and the specialist (IQ outliers) will take care of the grown up stuff. Third, lower IQ people make more babies (we know this is true) thus another driver of stupidity. So how is this decrease in intelligence masked? As a guy named Flynn pointed out, people are becoming better at applying what intelligence REMAINS to abstract modern tasks, and because an IQ test is abstract (on a computer screen or paper) modern people (who are no longer hunter/gatherers, or farmers) do better at these abstract tests. This masks the fact that their true genetic intelligence is decreasing. I don’t think it is fair to say that “the kinds of things that the intelligence test measures are no longer the kinds of things that our intelligence needs to master”, Flynn effect is saying these are exactly the types of things we need to master, and that’s why we are doing better on these tests. Flynn effect also addresses nutrition. For example say the true genetic intelligence of people in a starving country is 90. However they are starving, so their brains don’t develop fully, and they grow up with a 15pt impairment, thus 75IQ. When they become a developed country their IQ increases to 85. Note I’m still leaving a 5pt impairment there. What Flynn doesn’t address is that just because you are not starving, doesn’t mean you aren’t suffering impairment from diet (industrial revolution diets are a disaster of sugar, while flour, and grain/seed oils and there is evidence this impacts intelligence). And this could actualy be why Flynn effect is decreasing; because the types of food that make people obese also makes them stupid. Regardless, Flynn effect is not real genetic intelligence, as he himself admits…it’s just a diminishing of the impairment due to decreasing malnutrition, and abstract society people doing better on abstract tests. Technology keeps advancing despite intelligence retreating, because it is driven by the count of geniuses, which is driven by population. If we define genius as 160, then its rarity 1 in 30,000. So in the Upper Paleolithic you only have 1 genius on the planet, and today you have 200,000! There is no evidence that standard deviation has changed over time, or that % positive outliers have changed over time. Avg IQ could fall to 80, but with a pop of 8B there will still be individuals 6+ std dev out, and they will lead things forward, while the dumb masses become dumber. Population thus also masks the decline in avg intelligence, it makes us look like a bunch of geniuses, when in fact we are getting dumber. “The basic premise seems to be: the vast majority of people have more exposure to education than every before, but there seem to be fewer top intelligences.” No, nobody is saying that. I think that is where you went astray. People are saying genetic intelligence has been decreasing for thousdands of years, education is increasing, IQ test performance has been increasing over the last 100yrs (the mean moving up) due to the abstract nature of modern life and lack of starvation, but recently that has begun to lose steam and even reverse (decreasing mean), and std dev is basically the same. At least that’s what the observations point to, and it seems reasonable to me.

Bingo! Pretty straight forward imo. Schools dumb you down. Even the most intelligent will become a retard after graduation. I tend to believe that men in the early 1900s were way smarter. How many of them have post-graduate degrees?

First, it is the ‘educated’ men. Now it’s the ‘educated’ women. You put the ‘educated’ man and woman together, what do you get? An ‘educated’ child. LOL.

What was the IQ score of people in the pleistocene, and what is the IQ score of those people today? If you say IQ is the wrong test, then what test are you using to measure the intelligence of human beings today and pre-industrial or pleistocene life?

Cranial capacity? Really? That’s your measure of intelligence? It’s the organization of the brain that seems to have made a difference between us and most other animals at least as much as brain size. Are you saying that people with small hat sizes are noticeably dumber than people with large hat sizes? I’m curious where the data is that shows that.

And does our theoretical maximum intelligence actually matter at all if no one is ever educated or has the nutrition to make use of it. Perhaps our pleistocene ancestors would grasp quantum gravity more rapidly if they weren’t busy running away from tigers or trying to figure out how to survive beyond the age of 30, but the fact is that even proportionate to population, we have far more people who understand quantum gravity today than we ever did in the pleistocene.

Even if you could make an accurate measurement of average ancient intelligence capacity, how is that at all meaningful to today when in fact virtually none of these people could make much use of that higher intelligence capacity created by that amazing cranial capacity.

Finally, if one is saying that average intelligence has declined over the last decade or two, it seems that bringing in an evolutionary explanation stretching back to the pleistocene isn’t going to give you much mileage. It’s much more likely that new chemicals in the environment, changes in the way we educate and promote people matter. Diet may well make a difference, but I’ll bet it has more to do with processed food, hormones, pesticides, etc., rather than some genetic explanation that says that the last two decades of test scores are part of a 10,000 year genetic deterioration.

I’m not saying that that some genetic decline couldn’t be true (similar to the spermcount problem), but you need a different kind of evidence to make that case, and I’m not sure where you’re going to find it. Crainial capacity is notoriously suspect. We used to make the argument that men were innately smarter than women because men had larger cranial capacity. Until of course we discovered that women actually had larger cranial capacity on average because men seem to have thicker skulls, and then that explanation went out the window. Perhaps cranial capacity makes sense on 10,000 and 100,000 year timescales, but it is unlikely to be something that is going to make a difference between 1950 and 1990.

Uhh no. We aren’t talking about education, we are talking about genetic intelligence. These are separate things.

Just trying to get people up to speed, most of what you discuss was already answered in my post.

We analyze using the evidence which exists, not the evidence which does not exist. And the evidence which exists all points to genetic intelligence increasing for 2.5M years, and then decreasing. There is ZERO evidence that genetic intelligence is increasing, nobody real thinks that is happening.

As for men/women, men have higher avg IQ by around 3-5 points, but more importantly they have massively more outliers (wider std dev). At 145+ men outnumber women 8:1. This too makes sense when viewed thru the evolutionary lens. And yes it fits with cranial capacity also.