
The Paradox of the Elephant Brain - dnetesn
http://mitp.nautil.us/feature/227/the-paradox-of-the-elephant-brain
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nickledave
Herculano-Houzel has published a number of surprising findings using the novel
technique she invented for counting cells in the brain. In case you're
interested:
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4380666/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4380666/)

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pjreddie
Going back to the magpie though, they don't have a cerebral cortex at all, yet
exhibit remarkably intelligent behavior (tool usage, self-recognition). So,
what's up with all the smart corvids?

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otabdeveloper1
It's almost as if we don't know everything and the animal brain is actually a
bit more complex than a primitive multilayered perceptron neural network!

(Excuse me for the sarcasm.)

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giardini
tldr; The article states:

"The superior cognitive capabilities of the human brain over the elephant
brain can simply—and only—be attributed to the remarkably large number of
neurons in its cerebral cortex."

which simply does not follow. Well, that and _we cook_!

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antome
Furthermore the Long-finned pilot whale has been shown to have more neurons in
the Cerebral cortex than humans. Given the lack of large-scale research in
this area, it is not unreasonable to think that several other dolphin species
could also beat this count.

[https://en.wikipedia.org/wiki/List_of_animals_by_number_of_n...](https://en.wikipedia.org/wiki/List_of_animals_by_number_of_neurons#Cerebral_cortex)

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acqq
The author of the article argues that stereology is less suited for making the
whole brain cell counts, and it can be that her method gives different
results, just like it gave for elephants:

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4380666/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4380666/)

"Subsequent work using computer simulations, however, revealed that a
considerably larger number of cells should be counted (e.g. 700–1,000, Schmitz
and Hof, 2000). It is possible that too small of a sample size may explain
some of the discrepant results seen in stereology studies."

Of course there's chance that her approach will confirm the current estimates
for dolphins, and then the simple count of the neurons in the neocortex will
be too simple explanation to be valid.

In computer terms, it's easy to show: the transistor count of the CPU is not
the only count that can predict the suitability of CPU for some specific
tasks. Her research showed that the brains of elephants do have bigger total
count of the neurons, compared to the total count of the neurons of human
brains.

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visarga
The number of neurons is not all there is to it - we know from deep learning
that we can retain 95% of the accuracy with just 5% of the weights (synapses).
So there could be a 20x variation just from the degree of network
optimization. The elephant brain is just 3x the weight of the human brain.

Another aspect - consciousness is not created by the brain - it is a result of
the brain being in the world (in other words the "agent" being exposed to
experiences). To reduce consciousness to a function of the brain is to
overlook a force that is guiding, teaching and limiting the conscious
activity. I think consciousness, as a concept, is more related to
reinforcement learning than the brain.

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api
It's not just weight -- it does seem to actually have more neurons and glia
numerically. The rest of your comment stands and is probably the most likely /
default hypothesis, but there are others.

What if elephant brains actually do outperform ours but along an axis we're
not seeing because... well... it's something we suck so bad at that we can't
see it in another being.

A relevant story:

I've seen people with insanely great social abilities. I had a friend once who
could walk into a room and tell me the personal situations of everyone and we
checked this once by starting a few conversations. She had a near-perfect hit
rate at spotting things like people who had recently broken up, people who
were unemployed, etc. It was spooky.

I'm nowhere near this good and might be "on the spectrum," though it's also
possible that my preference for technical and intellectual stuff from a very
early age just wired my brain for them. My brain only has so many neurons so I
assume there must be a trade-off in what we dedicate them to. The woman in my
story above came from a weird kind of complex abusive family and extended
social situation (can't go into it and would be too long), so for her she
might have dedicated a ton of mental resources to understanding social
environments as a matter of personal safety as a child.

I was much more "spectrum"-y when I was a kid and a teenager. For the first 18
years of my life I was kind of oblivious to deep social cues. My social
awareness improved really dramatically in my 18-25 years, and it felt very
much like being color blind and then gradually acquiring the ability to see
color. I became aware of cognitive abilities and aspects of existence that
were all around me for the first 18 years of my life but that did not "exist"
for me.

As I acquired these abilities I started to spot them and have respect for them
in others. Prior to this I didn't notice any variation in other peoples'
social abilities because I couldn't notice variation in an ability I didn't
have and couldn't perceive.

Neurons are demanding cells. They eat a lot of glucose and need a lot of fats,
oils, and micronutrients for their formation and maintenance. It doesn't make
evolutionary sense that elephants would maintain a bunch of neurons that do
nothing to boost their fitness. Brains aren't externally visible like antlers,
tusks, etc. and so serve no _intrinsic_ display or offense/defense function.

It _could_ be an evolutionary accident of hypertrophy. Evolution is not such a
greedy optimizer that this is impossible. But the high cost of brains is
certainly suggestive of evolutionary benefit.

Edit: I've brought up these kinds of ideas in other contexts and I've found
that they bother some people. People almost get defensive, like it's a
_personal_ affront to suggest that there might be alien cognitive abilities. I
feel that if we ever do meet actual ET aliens we are going to get some kind of
massive reality check. The obligatory XKCD:
[https://xkcd.com/638/](https://xkcd.com/638/)

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ErikVandeWater
Although I don't disagree with your perspective that there could be additional
senses invisible to us, I think the explanation for the size of the elephant
brain is ultra-simple:

"The cerebellum receives information from the sensory systems, the spinal
cord, and other parts of the brain and then regulates motor movements. The
cerebellum coordinates voluntary movements such as posture, balance,
coordination, and speech, resulting in smooth and balanced muscular activity."

 __Huge body = huge cerebellum __

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jimbokun
I'm sure the trunk alone requires lots of neurons to manipulate.

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circlefavshape
"The superior cognitive capabilities of the human brain over the elephant
brain ..."

Are we _sure_ our cognitive capabilities are superior? How do we know we've
been doing meaningful experiments?

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viach
Coz there are no elephants posting on HN?

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MacsHeadroom
That could have more to do with our versatile anatomy than a difference in
cognitive capabilities.

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ccozan
But that is exactly the point: the brain draws its cognitive power from the
number of inputs and not from mass.

Just think of the human hand or the mimicry we can express and how many
muscles and associated sensoric feeds our brain continuously. Mass is
relevant, but up to a certain degree.

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marcus_holmes
I don't get the reference to cooking our food. Why does cooking our food
enable us to have a bigger cortex?

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PhilWright
Cooking food breaks down the cell walls and so makes it much easier to digest.
So you can get more of the calories out of the food you consume. You spend
less time gathering and eating and free up time for thinking.

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taneq
Pet theory time: There's a lot of speculation about why human females have
greatly enlarged breasts compared with other primates. These theories usually
revolve around some alleged similarity between boobs and bums, which let's
face it, is quite a stretch, especially when you consider other primates. A
female chimpanzee's chest looks absolutely nothing like its butt.

However, humans _do_ have much larger brains than other primates, and those
brains grow very fast immediately after birth. My theory is that after the
advent of cooking, human brains were able to increase in size thanks to the
increased dietary energy density of our new diet. Human breasts then had to
increase in size in proportion with the nutritional requirements of those
infant brains, which had to grow faster than previously.

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dragonwriter
> There's a lot of speculation about why human females have greatly enlarged
> breasts compared with other primates. These theories usually revolve around
> some alleged similarity between boobs and bums,

That's the distorted popular version. The more common scientific version,
AFAICT, is that they evolved in certain other upright primates to resemble
swellings in the genital/buttock region of non-upright forbears and provide
similar sexual signalling.

> Human breasts then had to increase in size in proportion with the
> nutritional requirements of those infant brains, which had to grow faster
> than previously.

This speculation would make sense if there was a relation between the quantity
of fatty tissue which determines breast size and milk production. But, there
isn't, so...

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taneq
It still works if initially milk-gland size was selected for, followed by
runaway sexual selection. :)

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lend000
The encephalization quotient seems to suggest that a certain amount of brain-
power is required to process nerve signals subconsciously (pain/touch/etc.).
Larger animals have more nerves, and therefore need larger brains to perform
the same abstract thinking activies, i.e. IQ. We can further combine this with
the diminishing return of further reducing the brain size for an animal that
is already large/ consuming large amounts of resources.

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wwarner
a great read -- almost as good as Franz de Waal's "Are We Smart Enough to Know
How Smart Animals Are?" (where this study and others are cited)
[https://www.amazon.com/Are-Smart-Enough-Know-
Animals/dp/1783...](https://www.amazon.com/Are-Smart-Enough-Know-
Animals/dp/1783783044) .

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Gravityloss
I think the article could be significantly shorter. It says the same thing
about six times.

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jackwest
"No, the human brain does not have more neurons than the much larger elephant
brain—but the human cerebral cortex has nearly three times as many neurons as
the over twice as large cerebral cortex of the elephant."

Does the mass of neurons in the cerebellum give the ele' any greater
capability? Longer memory for revenge, perhaps?

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nickledave
Probably has to do with control of the trunk and "infrasonic vocalizations"
[http://www.karger.com/Article/PDF/345565](http://www.karger.com/Article/PDF/345565)
if you believe the cerebellum mainly contributes to movement. Some argue that
it also contributes to "cognition", as Herculano-Houzel points out.
Interesting that her group previously reported that, across evolution, brains
maintain a linear relationship between number of neurons in neocortex and
number of neurons in the cerebellum:
[https://www.ncbi.nlm.nih.gov/pubmed/20300467/](https://www.ncbi.nlm.nih.gov/pubmed/20300467/).
The finding that 97.5% of neurons in the elephant brain are in the cerebellum
would seem to contradict the idea that brains maintain a constant
neocortical/cerebellar neuron ratio. The elephant paper attributes the huge
number of cerebellar neurons to sensorimotor input, i.e., probably trunk
stuff:
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4053853/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4053853/)

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0xdeadbeefbabe
It bugs me when a complicated neural phenomenon reduces to "size matters".

