The alternative hypothesis - that the brain has independently evolved twice - is in my opinion even more interesting. If true, it would seem to have implications for estimates of how easy it is for life to evolve intelligence.
Whatever the origin of the brain organ in evolution, There has certainly been a lot of novel inventions after that time. A lot of interesting "design" has happened for a long time after that invention, separated by divergence.
Cephalopods are very distantly related to us. Our last common ancestor with cephalopods is also our last common ancestor with slugs and hookworms. Yet many species are obviously highly intelligent. Their intelligence seems to work very differently from vertebrate intelligence.
So, it's interesting thing that some descendant species of whoever invented brains opted out. But either way some sort of convergence did happen. Maybe brains evolved twice. Maybe they evolved many times from a common primitive nerve bundle that performed a very different function. Maybe this happened in a tangle of back and forth.
The aye-aye lemur and the striped possum both evolved a long bug catching finger. We know that it's convergent rather than common ancestry because (among lots of reasons, but this is a neat example) it's a different finger. But, they both had fingers to elongate in the first place. So, given the same machinery to evolve and the availability of similar ecological niches (no woodpeckers, lots of bugs) they came up with a smiler solution.
We know that brains, and their components are very flexible even in a mature organism. So it makes sense that evolution is wild and creative, repurposing the tool constantly. I mean the diversity in sense perception in different animals seems like evidence of radically evolving brains over relatively short periods of time. Even entirely new senses (eg echolocation) seem to evolve fairly easily and quickly.
TLDR: depending on what your precise definition of "brain" is, this seems very likely. Aye-ayes & striped possums both have elongated fingers that evolved separately from regular fingers. The fact the they both evolved from regular fingers is interesting, but neither here nor there for most interesting conclusions. Brains are probably like this, but way more interesting any mysterious.
^I feel like I have to credit Douglas Adams who wrote beautifully about these animals.
Interesting that you chose cephalopods - their eyes work similarly in the "basic layout" to vertebrate eyes but cephalopod eyes have a few key differences, which may again be convergent evolution, since the most recent common ancestor didn't have eyes, only a photosensitive spot (which is still present in jellyfish).
So I was using "brain" in the same sense as the article, as a shorthand for "central nervous system".
I think we already knew that once you acquire a CNS, it can evolve rather rapidly to quite complex brains, and that doesn't seem intuitively surprising. It's that first leap to a basic nervous system which seems like the high activation energy barrier, and if it may have happened twice rather than just the once, then I find that interesting.
The 'earliest known example' (520mya) discussed dates to around the cambrian explosion, the geological period where the fossil record is rich with "earliest examples" and type specimens for phylums.
Maybe another way to put it is 'The definition of brain used in this article might apply to organs other than the brain in modern species." It's basically a nervous system, centralized or not. Who knows what it did or what it was for. It may have a predecessor outside the animal kingdom. Plants have sensory perception, or some version of it.
I'm not disputing the claims in this article or anything else. I'm basically agreeing with you.
Whether or not some nervous system, nerve cells or complexes of nerves evolved 520+mya and were 'lost' in some phyla or was evolved through convergent evolution a little later, it's partially a semantic issue: do we call something a brain. Most of what makes a brain a brain probably came later and evolved separately in different phyla. This means radically different ways of doing things.
BTW, Richard Dawkins really turned me on to evolutionary biology (a side gig, when he's not arguing with dummies) in some of his books. "Ancestors Tale" is awesome for really getting the "phylogenetics" way of thinking discussed here.
> Cephalopods are very distantly related to us. Our last common ancestor with cephalopods is also our last common ancestor with slugs and hookworms. Yet many species are obviously highly intelligent. Their intelligence seems to work very differently from vertebrate intelligence.
Similarly old low bit-width CPUs are "as" potent as nowadays CPUs according to the work/dataflow they have to handle. Or even OSes, win95 could do a lot that a recent Linux/WM can do at a tiny fraction of the structural cost/complexity. Also text encodings.
Key point: evolution does not necessarily working towards more complexity or a specific endpoint. Rather, the unique selection pressures that exist when organisms attempt to reproduce vary, as do the particular genetic changes that happen due to any number of factors (mutation, viruses, gamma rays, copy errors, bacterial absorption, whatever). Each generation may face similar or different pressures. Certain mutations may be more or less likely. In some cases, the mutations that survive may be pure random chance. In others, only a specific mutation may have saved the organism's particular genes from extinction. The future organisms and genes that emerge from this chaotic process are unpredictable. Sometimes those organisms will lose features, sometimes gain, sometimes have weird changes that don't appear to make sense. All that matters is: do the organisms continue to reproduce successfully generation after generation?
Indeed. My memory is failing me but I seem to recall having heard or read someone talking about the brain and stating that its sole purpose is to move the body. Thus, an organism that does not move does not need a brain, and as a proof of this idea he mentioned that some animals, like some medusa, loose their brain once they fix themselves to the floor (turning into polyps in the case of medusa).
Daniel Wolpert has a TED talk where he makes this point [1]. And I think he's basically got it right. Certainly there are organisms that can move without a nervous system (single celled amoebas, venus fly traps, etc) but by and large you need an (electrical) brain if you are going to react to something on a fast timescale.
Another example of where more brains doesn't necessarily mean evolutionary advantage is modern humans. It can be seen all over the world that the less intelligent procreate more.
> It's kind of a joke, but also really not. It's frightening.
It is a joke.
Idiocracy relies on the assumption that the "more intelligent" people are snobs and too busy and too perfectionist with their life to have children, while the "less intelligent" people are mostly having sex and are too lazy to apply contraception properly.
Essentially, the first half of the movie is a justification for elitism.
I'm less afraid of Idiocracy to become true, but more afraid of politicians acting as if they believed in this movie.
The second half of this movie is more interesting, though. It may be interpreted as an analogy of how the most gifted people (in the sense of "intellectual giftedness") may feel living in today's world. (by putting today's "normal" people into a dumb world) But even that is, of course, a funny hyperbole, and nothing to take too seriously.
Have you ever heard the phrase "there is truth behind every joke"? It is relevant here.
The joke is in the exaggerations and charicatures. The truth is what is real that would cause this joke to be made in the first place.
Obviously smart does not equate to "snobbery" or "perfectionism". And less smart does not equate to "more horny". It is a comedic layer added by the directors to make you laugh, because it is a comedy.
But the truth beneath the funny is that less smart people generally make poorer life decisions. For many people in many contexts, less children for a longer time is a smart life choice, and more children more quickly is not. Because more children more quickly is, in most contexts, in the category of poor decision, it tends to happen more with less smart or educated people.
I don't see how it is an argument for elitism at all. It's an argument for promoting education.
> I don't see how it is an argument for elitism at all. It's an argument for promoting education.
I see it the same way, as an argument for promoting education, throughout the whole population, not just some "elite".
However, I've also seen people arguing for the opposite direction: That the "elite" must be protected from the "mob", must be socially more separated than it already is, or it will die out. And that it must become more attractive especially for the "elite" to become children, while the "mob" will take care of themselves. (The argument wasn't phrased with exactly those words, but the sentiment was essentially that.)
But do you have evidence for the assertion that there is a negative correlation between intelligence and reproductive success? I read somewhere (can't find the source) that smart guys on average actually have more children than stupid ones, and that for women fertility is about the same.
I've seen multiple sources showing reduced fertility in high-IQ females (across multiple countries.)
The culprit, however, doesn't seem to be raw intelligence as such, but modern western education, which seems to have a dose dependent sterilizing effect on females. In that light, high IQ isn't fertility-reducing in itself, rather low IQ is protective against modern western education.
Would love to see some proper evidence for these claims.
One can easily see that clever ladies tend to focus much more on long education/career, rather than jumping straight on babies-making bandwagon. Also, finding good partner to have kids with seems much harder for them (well, for clever guys sadly too). Considering most university level education ends when people are around +-23 (not even going into PhD ones), and then they just become fully autonomous and step in working treadmill (earn->spend->earn-> cycle), I would name culture/work/environment situation or pressure for that.
Also generally, more clever people focus more on quality rather than quantity, and babies are no exception. Norm are 1-3 kids, not because women are not fertile anymore (unless climacterium is reached), rather time & resources are considered.
Even this is very simplistic & dumbed down view on these matters.
It's not just modern western education. Basic education for girls in third-world countries is associated with lower birth rates. Additionally, comparatively minor decreases in poverty in undeveloped countries correlate with declines in birth rates -- possibly because declining poverty usually goes hand in hand with declining infant mortality. The latter being one of the biggest reasons that the average birth rates in developed countries have dropped from 30-40 per thousand to 10-15 per thousand in just the past 150 years.
"modern western education, which seems to have a dose dependent sterilizing effect on females. In that light, high IQ isn't fertility-reducing in itself, rather low IQ is protective against modern western education"
I admire the way you phrased this.
The difference in size between educated and uneducated families might be very large in societies that are in transition on the development scale, but I wonder if the same is true in a society that is stable on that scale. Do uneducated families in the West have more kids than educated families, or do they just have their 2.1 children earlier in life?
First, you have to avoid conflating culture with genetics. No one 'evolved' to be a good engineer: there has been an insufficient amount of time and probably selective pressure for an engineering gene to arise, spread, and flourish. Instead, we've developed an engineering culture, which can readily spread independent of the genes of the individuals currently carrying the engineering culture. Indeed, even today after a century or two since the dawn of modern engineering there are many fantastic first-generation engineers.
Second, I don't really believe that modern civilization is deficient as an environment for breeding intelligence. Fundamentally, intelligence isn't excellence at a particular culture or being supremely well suited to a particular niche, intelligence is adaptability. Intelligence lets us survive in a great variety of niches, that our ancestors never had the chance to evolve for, to learn new skills and develop new cultures.
Unlike the static worlds of yesteryear where generations could go by without a change and you could expect to live a life identical to your parents with (maybe) different names for the principals involved, everything changes now constantly. Culture, technology, jobs, food, language, social mediums. Everyone has to deal with it. People may not need to demonstrate their intelligence in a way that pleases a certain subset of the intellectual elite, but they're being required to adapt -- by their peers, their mates, their potential mates -- on a scale that has rarely if ever existed in human history.
Idiocracy is a movie, it's entertainment. There's also two sides to it, one of which a lot of people don't seem to pick up on. The protagonist of the story, the smart guy in the future of idiots, never really applied himself, he was content with being smarter than the average idiots, and he thought that was good enough. It wasn't until he got off his ass and engaged with the world that things started to get better.
Besides which, it's fictional. While there is some truth to the fact that "less educated" people tend to reproduce at a comparatively higher rate than the more educated, it's a fallacy that somehow this is resulting in a "dumbing down" of the human race. For example, raw IQ test scores have been increasing over time quite dramatically (IQ is always normalized to the mean so 100 IQ is by definition the average).
Idiocracy is an entertaining story, and it holds some lessons worth taking to heart, but it is not the truth.
But that relies on smart people having figured stuff out to the point where it is no longer an advantage. If human intelligence declined to the point where we lost that kind of knowledge, then being smarter could probably become a benefit that's selected for. Rinse, repeat?
First, I never said anything about western culture. (Note that the example is inside America.) Second, the poor generally don't have the same access to good education so in general it is true. Third, I edited my comment because I know they're not equal and it was a mistake.
