Humans getting dumber, scientists warn

Phew, I think I jammed thru responding to most of the posts with my morning coffee!

Yes, this topic requires doing actual study/work. Intuitive analysis works on simple problems; basically applying intuition, instinct (common sense), to reach an easy answer. It doesn’t work on complex problems, or emotionally charged ones, like a species analyzing it’s own decrease in intelligence. That requires picking a formal analytical technique, the right one for the job, and long hours of actual work.

People might be “book smarter” today, but many lack basic common sense. As a wiseman once told me, common sense ain’t too common.

Common sense says defer to purealpha on this topic. He explains why in post 42. Yep, ain’t too common.

You should only invest in the S&P 100 or perhaps if you’re feeling like a wild man, the S&P 500. After that, the high IQ premise becomes highly suspect, and the smaller the cap, the less clear the connection becomes. Under $500 million and there is about a 50% chance you are investing with sociopaths and/or bumbling idiots (gets real fun when you get both in the same place and can get short). Clearly there is a gap between S&P 500 and $500mm so I am just using those for illustrative purposes. There is plenty of bad behavior in big companies too.

I only have a son, but I can tell you that his “maleness” became readily observable at age two despite the fact that his mom stays at home with him and does her best to make him a calm neat freak. At two he began to love sports (mostly basketball, but that evolved to several sports over the next year), trains, firetrucks, and wrestling with mom and dad. Things like bulldozers immediately grab his attention. When we go to a toy store, he walks right past all of the girl toys right to the boy toys.

He spends much more time with his mom, who’s a total girly girl, and I’m not really into sports, trains, or firetrucks. So the idea that kids develop gender roles based on their parents behavior is a complete joke to me.

So the other drivers cancel out its relationship to population growth and magically make it a linear relationship?

I agree with everything you just wrote. My point is that using tool use as a proxy for intelligence is problematic. Is the first Chimpanzee who sharpened a stick to use for hunting more intelligent than the modern day human? Chimps have been shown to use tooks like this.

Also, there was very little development of technology early on and things accelerated rapidly, probably as you say due to increased interconnectedness and specialization. Again, I am saying that tool use as a proxy for intelligence does not make sense to me. I could sharpen a stick or an arrowhead. I could not make metal, and neither could humans 30k years ago (that I’m aware). I would go so far as to say that very few humans have made metal from scratch all by themselves, and those that have did it as an experiment to see if they could.

Man builds toaster from scratch:

It just sounds like a theory (and not a bad one) with not much backing it up. Maybe I’m just slow today.

Indeed, it seems like there are various theories:

Some believe the erosion of our gray matter means that modern humans are indeed getting dumber. (Late-night talk show hosts, take note—there’s got to be some good comic material to mine here.) Other authorities argue just the opposite: As the brain shrank, its wiring became more efficient, transforming us into quicker, more agile thinkers. Still others believe that the reduction in brain size is proof that we have tamed ourselves, just as we domesticated sheep, pigs, and cattle, all of which are smaller-brained than their wild ancestors. The more I learn, the more baffled I become that news of our shrinking brain has been so underplayed, not just in the media but among scientists. “It’s strange, I agree,” says Christopher Stringer, a paleoanthropologist and expert on human origins at the Natural History Museum in London. “Scientists haven’t given the matter the attention it deserves. Many ignore it or consider it an insignificant detail.”

But the routine dismissal is not as weird as it seems at first blush, Stringer suggests, due to the issue of scaling. “As a general rule,” he says, “the more meat on your bones, the more brain you need to control massive muscle blocks.” An elephant brain, for instance, can weigh four times as much as a human’s. Scaling is also why nobody seems too surprised by the large brains of the Neanderthals, the burly hominids that died out about 30,000 years ago.

The Homo sapiens with the biggest brains lived 20,000 to 30,000 years ago in Europe. Called the Cro-Magnons, they had barrel chests and huge, jutting jaws with enormous teeth. Consequently, their large brains have often been attributed to brawniness rather than brilliance. In support of that claim, one widely cited study found that the ratio of brain volume to body mass—commonly referred to as the encephalization quotient, or EQ—was the same for Cro-Magnons as it is for us. On that basis, Stringer says, our ancestors were presumed to have the same raw cognitive horsepower.

I agree, I don’t see why brain size should necessarily be linked to human intelligence, in the current period perhaps, but it may not be necessarily so throughout history. Not all parts of the brain are linked to cognitive ability, and I don’t think we can rule out the structure of the brain changing in this time period. So while there may be a correlation of 0.3-0.4 for the current population…it seems to me that using that data to determine the IQ of pre-ice age humans is using it out of context…

i was more so asking whether this 8:1 ratio provided is a NA ratio or a world ratio. obviously 80% of the female population is groomed to not to learn math or develop their mind. in many OECD countries, girls score better in math than boys. with math being such an important part of of IQ measurement, i could imagine that the lack of high IQ females is a lack of brain development and math education in potential high IQ females.

and yes, the measurement/proxy issue is a major problem with grand conclusions.

The sperm whale is the world’s smartest creature because it has the largest brain (about 18 pounds). Since the human brain is only about three pounds, the sperm whale must be six times smarter.

*Tee-hee* he said sperm.

My point about “crainial capacity explains everything” is about how purealpha’s argument works, not about what the data says.

Purealpha says that the correlation between cranial capacity and intelligence is 0.4. It would be good to get a reference to where that data point comes from, because I have no idea if cranial capacity is being measured between adults of different geological eras, human adults vs human children, humans vs primates or other animals, or if they gave human adults IQ tests before cracking their skulls to see how big it is inside. We don’t know how they’ve measured intelligence, whether it is IQ or how many dots they were able to engrave on a stone in 1 hour, but we do know that it must be some kind of a quantitative measure, because otherwise a correlation coefficient would be completely the wrong statistic to use.

Even if the correlation is indeed +0.4, that suggests that 0.16 or 16% of the variance in intelligence is explained by cranial capacity, which leaves another 84% explained by other factors. That seems to be a lot of “other factors” that can go into determining whether we are getting smarter or getting dumber as a genotype (there, I used a big anthropological-sounding word). So cranial capacity may have diminished a bit (we haven’t established how much).

Even if the correlation were exactly 1, it is still quite possible that the line it lines up on is IQ = CranialCapacityInLitres * 0.000000000000000001 + 100, and you would still get a correlation of 1.

So we would have to see this study you have. Since you’ve spent so much time studying and it is at the center of your argument, please give us a link so we can see if it makes any sense for you to use the results.

The challenge with evolutionary explanations is that one can casually come up with evolutionary explanations to argue just about anything, just as one can easily invent reasons for almost any correlation between variables chosen at random.

The way to be sure that your theory or explanation is right is not to sit there and say “I’ve studied it, and it makes sense to me,” but to compare the explanation with alternatives and see whether it has more evidence or than the others, or if there are things that it predicts that have not happened, but which other things do.

We all have pet theories, and yours is not implausible, but you have not presented data that gives strong support to it, and you are busy saying that other explanations about intelligence aren’t correct, because you are asserting yours is the dominant explanation for the original observation that average IQ test score has declined over the past 60 years.

If that’s true, and it is driven by a decline in cranial capacity, and the other explanations that people have been floating are truly bogus, the way you’ve been arguing, that that suggests that the % decrease in cranial capacity in the last 60 years should be approximately (% change in IQ) / CranialCapcityBeta.

For a 9% decline in intelligence, assuming a cranial beta of around 1, if your argument is driving this, we should see a decline in cranial capacity of around 9%. That should be something easily observable, and not hard to verify even if the cranial capcity has declined by half that since 1950. If the beta is less than 1, the decline in cranial capacity should be even more pronounced and visible. If beta is greater than one, then it should be noticeably obvious to the casual observer that people with bigger heads are more intelligent, the way it’s obvious that people with bigger biceps can generally lift more, and really it would have to be greater than about 2 or 3 before we might start to think that cranial capacity had declined in the last 50 years unnoticed (by doctors at least).

But this all assumes that the correlation between cranial capacity and intelligence is actually substantively meaningful, when - even if the 0.4 correlation is correct - 84% of the variation in intelligence is still determined by “other factors,” which seem much more likely to be the right explanation for what’s going on since 1950.

Perhaps our cranial capacities are declining since the agricultural revolution. It is true that anthropologists find that the hunter-gatherer diet was more nutritious and varied than the early-agrarian diet, which had a tendency toward sesonal monocultures. The idea was that you could sustain a larger population with less overall labor and greater reliability of food sources this way, but it was a nutritional step backward. It was a trade off that may well have affected our brains somehow, but it also permitted specialization of human intellects that brought us forward and created things like writing and engineering and science and all the stuff that we actually think of as being signs of human intelligence.

It’s not that your theory is completely implausible (other than as an explanation for the decline in intelligence test scores since 1950), it’s just that there are too many other confounding factors for you to dismiss the other explanations the way you have.

But we all have our pet theories, and now we know yours.

I don’t know why I keep clicking on this thread, it just makes me feel dumberer.

looking forward to dumb and dumber 2

Native (genetic) intelligence is irrelevant and probably always has been. Work ethic almost always trumps intelligence as long as you reach a certain threshold of competency.

Lotta long posts in here that I didn’t read (so sorry if I repeat anything), but I wanna throw out there that it seems like people should only be getting smarter as we have an unprecedented and still growing access to education nowadays. Knowledge about pretty much any topic you could possibly desire is literally at your fingertips, and more often than not for free. Ppl, however, rationally realize that there’s minimal reason to acquire knowledge if it’s not going to pay the bills. The tools are there for ppl to learn, now it’s just a matter of making it a financially worthwhile decision once again and then we’ll see improvement. Otherwise, who even cares (them included) how smart they are. You want the guy picking up your garbage speaking 6 languages, knowing how to code, and holding 3 doctorates? No, you don’t give a shit… and neither does he. The “dumbing down” of society is almost economically influenced as far as I’m concerned. That, or it’s because we don’t have 17 pound brains like whales. Either one.

Why does it matter? “When two trains moves through each other at the same speed then both of them are at relative rest with respect to one another.”.Similarly If average iq for entire homo sapiens drops to 70 in coming years…i don’t think it will matter on a relative basis…Obv there will always be outliers like Enstien in every generation.

There is a very simply explantion why they are all men. The reason is that men have more desire than women. Michael Jordan is a perfect example of this burning desire. I wouldn’t say MJ is a genius. He probably couldn’t solve a simple equation. But using his god given natural abilities, he was a genius at his field.

so um,yeah