38 ms·

Silly thought: if bigger NN's are better, shouldn't more neurons be better? Why aren't elephants smarter than us, despite having more neurons? https://en.wikip

Silly thought: if bigger NN's are better, shouldn't more neurons be better? Why aren't elephants smarter than us, despite having more neurons? https://en.wikipedia.org/wiki/List_of_animals_by_number_of_neurons https://en.wikipedia.org/wiki/List_of_animals_by_number_of_n... https://pubmed.ncbi.nlm.nih.gov/24971054/ https://pubmed.ncbi.nlm.nih.gov/24971054/

kemiller 5y ago
IANANS but my understanding is that neurons/body mass is more indicative. Large animals have more neurons because large bodies need more.
- salty_biscuits 5y ago
  They talk about the encephalization quotient, which is to the 2/3 power https://en.wikipedia.org/wiki/Encephalization_quotient https://en.wikipedia.org/wiki/Encephalization_quotient
cloogshicer 5y ago
You probably already know this (since you wrote "silly thought"), but real-life neurons are ridiculously more complex than simulated "neurons" in an NN. So the analogy doesn't really hold.
- pishpash 5y ago
  They're more complex in biological construction and in signaling mechanism, but no proof that they are more complex in function.
  - mattkrause 5y ago
    An individual biological neuron can compute a variety of functions, including max and xor, that a single perceptron can't (e.g., https://www.science.org/doi/10.1126/science.aax6239 https://www.science.org/doi/10.1126/science.aax6239 ). In general, one needs a fairly elaborate ANN to approximate the behavior of a single biological neuron. OTOH, a three-layer network is a universal function approximator and RNNs are universal dynamical systems approximators, so they are sort of trivially equivalent.
  - csomar 5y ago
    Do you think they have accumulated complexity for no reason. Because usually evolution kicks out things that aren't needed.
    - pishpash 5y ago
      For one they need to engage in metabolism and reproduction, but I'd like to see some argument of how neurons are more complex without those needs, e.g. do they compute some radically different class of functions than typical ANN's do, or require entirely different interconnections, etc.
- XnoiVeX 5y ago
  I think a lot of people on this thread are missing this critical insight.
  - visarga 5y ago
    You can simulate the data processing of a real neuron with 1000 digital ones, a small neural net. I think we read too much into the complexity of biological neurons. Remember they need to do much more than compute signals. They need to self assemble, self replicate and pass through various stages of growth. They need to function for 80-100 years. Many of those neurons and synapses exist only for redundancy and other biological constraints. A digital neuron doesn't care about its physical substrate and can be millions of times faster. They can be copied identically for no cost and cheaply fine-tuned for new tasks. Their architecture and data can evolve much faster than ours, and the physical implementation can remain the same during this process.
gfody 5y ago
are we certain they're not? i'm not sure we know how to measure smartness
- peterburkimsher 5y ago
  Dumbo is smarto! Elephants have bodies built like a tank (and used as such by Hannibal), but humans have better I/O ports. {reading, writing, listening, speaking, singing, typing, doing, going} Without opposable thumbs, an elephant is probably quite envious of human writing & typing. Let's use the privilege wisely to encourage one another, teach and learn from each other, from Donald Tusk, and give a helping hand.
  - Someone 5y ago
    But African elephants have quite versatile opposable finger-like extensions at the tip of their trunks (Asian elephants have only one such thing)
- beebeepka 5y ago
  I only stopped saying my cat is smarter than the vast majority of people I've met because she is no longer with us. I did, and still do, believe this to be true. Would love to befriend a bird
  - wizzwizz4 5y ago
    You can befriend corvids. Teaching them symbolic language is tricky, but they can trade and socialise and solve puzzles (if you manage to explain the puzzle).
joebob42 5y ago
Aside from other points, more neurons might be better "all else equal", but there are differences between our brain and an elephant's beyond just neuron count. It's like how just getting a bigger faster computer can help with your problem, but its less powerful than a new more efficient algorithm on the same computer.
World_Peace 5y ago
Elephants very likely could be more intelligent than us, it just seems that intelligence is a difficult thing to measure quantitatively.
- tshaddox 5y ago
  It may be hard to measure and even define precisely, but I think it's pretty clear that if we did agree on a definition in the context of this conversation it would be defined in such a way that humans are more intelligent than elephants.
- bee_rider 5y ago
  In particular, a given elephant might be "more intelligent" than a human -- we just happen to have evolved from a particular niche that has rendered us bizarrely good at abstracting knowledge and combining it with the knowledge of other humans.
  - notahacker 5y ago
    What is "more intelligent" if not "more capable of abstracting, synthesizing and sharing knowledge"?
    - jayd16 5y ago
      You'd also need the desire for such things.
    - bee_rider 5y ago
      How about the ability to solve novel problems? We have very good problem solving ability of course, but a superpowered ability to ask others how they solved the problem. If we wanted to somehow define a kind of 'brain horsepower' type intelligence, it seems to me that the former is closer to it than the latter, and it doesn't seem obvious to me that humans would necessarily take the top spot. Or that there's a reasonable/ethical way to test it -- let's take a human, elephant, crow, and dolphin, raise them in total isolation from the any community to get a measure of their untrained intelligence... we might get some interesting results on intelligence, but mostly we will learn something about ballistics as some ethics review board launches us unto the Sun.
alexpotato 5y ago
Because, IIRC, a lot of neurons are dedicated to motion/sensing. Bigger animals may require more neurons to handle moving larger and/or more complicated muscle groups. Interesting related point there is the encephalization quotient which is related to the predicted ratio of brain size to body mass. On the wikipedia page [0] they list the EQ for various animals. Humans are the highest but dolphins and ravens are not far behind.
- molticrystal 5y ago
  To further emphasize that having neural material focused on the appropriate functions is more important vs how much you have, here is a story about a guy whose brain is mostly hollow and filled with fluid, it probably did cause his IQ to be 75 and causes him weakness in his legs, but otherwise he lives a normal adult life more or less. https://www.newscientist.com/article/dn12301-man-with-tiny-brain-shocks-doctors/ https://www.newscientist.com/article/dn12301-man-with-tiny-b...
  - acchow 5y ago
    Doesn't this demonstrate the opposite of what you were claiming?
    - lacksconfidence 5y ago
      I feel like the quotes agree with parent: > “If something happens very slowly over quite some time, maybe over decades, the different parts of the brain take up functions that would normally be done by the part that is pushed to the side,” adds Muenke, who was not involved in the case.
    - Ajedi32 5y ago
      Did you see the scans? The dude's head is practically empty (brain 55-75% smaller than normal) and nobody even noticed until he was 44 years old and got an MRI.
    - divbzero 5y ago
      I think it’s that a priori you would expect a hollow brain to have a far more drastic effect and not allow for a mostly normal adult life.
btilly 5y ago
How do you measure intelligence? Elephants have much better memories than we do! https://www.scientificamerican.com/article/elephants-never-forget/ https://www.scientificamerican.com/article/elephants-never-f...
- Ajedi32 5y ago
  That article doesn't seem to support your claim. All of the feats mentioned would be entirely unremarkable in your average human.
  - btilly 5y ago
    Really? You'd immediately recognize someone you knew for a few weeks over 20 years ago? You wouldn't need a bit to try to figure out who they are? If so, then your memory is unusually good. I know that this is well beyond my capabilities. Nor do I have the ability to visit a place that I lived 40 years earlier and find my way around.
    - Spooky23 5y ago
      I think it depends on the intensity of the experience. I recently found myself in a hotel that I stayed in as a 7-8 year old in the 80s for a particularly memorable vacation with my extended family. It was funny that I still remembered the I unusual aspects of the layout and could spot many of the changes that had been made over the years. But if you asked me to describe someone I met for a few days in a business context in 2020, I’d have a hard time remembering detail.
    - Someone 5y ago
      How many other elephants did these elephants see in those 20+ years? It wouldn’t surprise me if that was fewer than 100. How many did they spend a few weeks or more with? It wouldn’t surprise me if that were less than 20. There also, AFAIK, isn’t evidence they remember _all_ other elephants they’ve shared time with for at least few weeks (I certainly do not rule that out, either, given the low number they likely will meet in their life)
    - 5y ago
juancn 5y ago
Well, biological neurons are much more complex than CS neurons (https://www.quantamagazine.org/how-computationally-complex-is-a-single-neuron-20210902/ https://www.quantamagazine.org/how-computationally-complex-i...). Also, you're working under the assumption that they are equivalent between mammals which as far as we can tell it's not the case (https://www.medicalnewstoday.com/articles/why-are-human-neurons-different-from-those-of-other-mammals https://www.medicalnewstoday.com/articles/why-are-human-neur...). So my guess is that the comparison is much more complex than just number of neurons.
fabiospampinato 5y ago
I read on wikipedia [0] the other day a fairly disturbing statistic related to this, apparently human men have on average a ~10% bigger brain than women. It'd be interesting to know if that translates to a higher neuron count or the difference in volume is due to something else. [0]: https://en.wikipedia.org/wiki/Brain_size#:~:text=In%20men%20the%20average%20weight%20is%20about%201370%20g%20and%20in%20women%20about%201200%20g https://en.wikipedia.org/wiki/Brain_size#:~:text=In%20men%20....
- andrewflnr 5y ago
  Probably just a consequence of overall physical size being larger. AFAIK there continues to be no evidence of a sex difference in overall intelligence, so slight difference in brain size is probably a red herring.
gwern 5y ago
Density is also important. If we look at other things - some recent studies have been done on number-counting (https://royalsocietypublishing.org/doi/10.1098/rstb.2020.0529 https://royalsocietypublishing.org/doi/10.1098/rstb.2020.052...) or bird brains (https://www.gwern.net/docs/psychology/neuroscience/2020-herculanohouzel.pdf https://www.gwern.net/docs/psychology/neuroscience/2020-herc...) - density jumps out as a major predictor. African elephants may have some more neurons, but the density isn't as great as a human where it counts, so they are remarkably intelligent (like ravens and crows), but still not human-level. There are diminishing returns in both directions. We have more neurons than any bird as much or more dense, and we have more density than any elephant with as many or more neurons. Put that together, and we squeak across the finish line to being just smart enough to create civilization. An analogy: what's the difference between a supercomputer, and the same number of CPUs scattered across a few datacenters? It's that in a supercomputer, those CPUs are packed physically as close as possible with expensive interconnects to allow them to communicate as fast as possible. (For many applications, the supercomputer will finish long before the spread out nodes ever finish communicating and idling.) But you need to improve both or else your new super-fast CPUs will spend all their time waiting on Infiniband to chug through, or your fancy new Infiniband will be underutilized and you should've bought more CPUs.
- user90349032 5y ago
  And yet, no animal except humans is self aware. Really makes you wonder why that is.
  - stjohnswarts 5y ago
    that is simply incorrect bonobos, orcas, elephants, dolphins, chimpanzees, etc have all shown degrees of self awareness.
    - stjohnswarts 5y ago
      Haha downvoted for stating the obvious and something that can be found in seconds on any google search. Never change HN.
tshaddox 5y ago
For one thing, when the article says "bigger" it means "more parameters," not "more neurons."
urthor 5y ago
If neural networks have shown us anything, it's that not all neurons are born the same. After all, even in nature there are multiple types of neurons. I imagine it's 100% dependent on the cardinal rule of neural networks: "Choice of training data is 10 times more important than the actual model." What we have over elephants are opposable thumbs, excellent eyes, and vocal cords. And crucially, we're generally speaking pretty slow, weak and useless. Except for our elaborate methods of I/O. Our entire success is based on a feedback loop. "If human uses their IO this way, human will get more food." Thus, we become ever more sophisticated at this. We are nothing if not a vehicle for using our high dexterity, low gross force, opposable thumbs in inventive ways to get food. Plus, we have a biological imperative to pass these techniques on as knowledge. A baby elephant can probably feed itself by eating green stuff at 1 year old (I know nothing about elephants). A human child realistically cannot independently scrounge up enough solid food to sustain themselves, until they're what, twelve? Twenty-two? Certainly no younger than eight. We have, almost certainly, the most useless progeny in the animal kingdom. Hence we invest an enormous amount of time and energy in education to make them able to feed themselves. So the tl;dr is 1) Human brains are pretty similar to the animal kingdom's. 2) Human opposable thumbs are world class. Pretty close to as good as it gets. Sight is also top notch, many animals have useless eyeballs. 3) Most human food is obtained by doing creative things with thumbs. This is very complex, and takes a lot of practice. 4) Human birth the most useless children in the entire animal kingdom. These children take decades to fully grow, hence we invest an enormous amount of time educating them in opposable thumbs. 5) Over time our education system gets better and better, and our list of clever things we can do with opposable thumbs get longer and longer. Essentially what we have over the other animals isn't neurons. What we have over the other animals is a data collection/cleaning/utilization cycle.
raxxorrax 5y ago
But only 1/3 as much in their cerebral cortex. Maybe having a multi purpose trunk does bind a lot of capacity?

kemiller 5y ago

IANANS but my understanding is that neurons/body mass is more indicative. Large animals have more neurons because large bodies need more.

salty_biscuits 5y ago
They talk about the encephalization quotient, which is to the 2/3 power https://en.wikipedia.org/wiki/Encephalization_quotient https://en.wikipedia.org/wiki/Encephalization_quotient

cloogshicer 5y ago

You probably already know this (since you wrote "silly thought"), but real-life neurons are ridiculously more complex than simulated "neurons" in an NN. So the analogy doesn't really hold.

pishpash 5y ago
They're more complex in biological construction and in signaling mechanism, but no proof that they are more complex in function.
- mattkrause 5y ago
  An individual biological neuron can compute a variety of functions, including max and xor, that a single perceptron can't (e.g., https://www.science.org/doi/10.1126/science.aax6239 https://www.science.org/doi/10.1126/science.aax6239 ). In general, one needs a fairly elaborate ANN to approximate the behavior of a single biological neuron. OTOH, a three-layer network is a universal function approximator and RNNs are universal dynamical systems approximators, so they are sort of trivially equivalent.
- csomar 5y ago
  Do you think they have accumulated complexity for no reason. Because usually evolution kicks out things that aren't needed.
  - pishpash 5y ago
    For one they need to engage in metabolism and reproduction, but I'd like to see some argument of how neurons are more complex without those needs, e.g. do they compute some radically different class of functions than typical ANN's do, or require entirely different interconnections, etc.
XnoiVeX 5y ago
I think a lot of people on this thread are missing this critical insight.
- visarga 5y ago
  You can simulate the data processing of a real neuron with 1000 digital ones, a small neural net. I think we read too much into the complexity of biological neurons. Remember they need to do much more than compute signals. They need to self assemble, self replicate and pass through various stages of growth. They need to function for 80-100 years. Many of those neurons and synapses exist only for redundancy and other biological constraints. A digital neuron doesn't care about its physical substrate and can be millions of times faster. They can be copied identically for no cost and cheaply fine-tuned for new tasks. Their architecture and data can evolve much faster than ours, and the physical implementation can remain the same during this process.

gfody 5y ago

are we certain they're not? i'm not sure we know how to measure smartness

peterburkimsher 5y ago
Dumbo is smarto! Elephants have bodies built like a tank (and used as such by Hannibal), but humans have better I/O ports. {reading, writing, listening, speaking, singing, typing, doing, going} Without opposable thumbs, an elephant is probably quite envious of human writing & typing. Let's use the privilege wisely to encourage one another, teach and learn from each other, from Donald Tusk, and give a helping hand.
- Someone 5y ago
  But African elephants have quite versatile opposable finger-like extensions at the tip of their trunks (Asian elephants have only one such thing)
beebeepka 5y ago
I only stopped saying my cat is smarter than the vast majority of people I've met because she is no longer with us. I did, and still do, believe this to be true. Would love to befriend a bird
- wizzwizz4 5y ago
  You can befriend corvids. Teaching them symbolic language is tricky, but they can trade and socialise and solve puzzles (if you manage to explain the puzzle).

joebob42 5y ago

Aside from other points, more neurons might be better "all else equal", but there are differences between our brain and an elephant's beyond just neuron count. It's like how just getting a bigger faster computer can help with your problem, but its less powerful than a new more efficient algorithm on the same computer.

World_Peace 5y ago

Elephants very likely could be more intelligent than us, it just seems that intelligence is a difficult thing to measure quantitatively.

tshaddox 5y ago
It may be hard to measure and even define precisely, but I think it's pretty clear that if we did agree on a definition in the context of this conversation it would be defined in such a way that humans are more intelligent than elephants.
bee_rider 5y ago
In particular, a given elephant might be "more intelligent" than a human -- we just happen to have evolved from a particular niche that has rendered us bizarrely good at abstracting knowledge and combining it with the knowledge of other humans.
- notahacker 5y ago
  What is "more intelligent" if not "more capable of abstracting, synthesizing and sharing knowledge"?
  - jayd16 5y ago
    You'd also need the desire for such things.
  - bee_rider 5y ago
    How about the ability to solve novel problems? We have very good problem solving ability of course, but a superpowered ability to ask others how they solved the problem. If we wanted to somehow define a kind of 'brain horsepower' type intelligence, it seems to me that the former is closer to it than the latter, and it doesn't seem obvious to me that humans would necessarily take the top spot. Or that there's a reasonable/ethical way to test it -- let's take a human, elephant, crow, and dolphin, raise them in total isolation from the any community to get a measure of their untrained intelligence... we might get some interesting results on intelligence, but mostly we will learn something about ballistics as some ethics review board launches us unto the Sun.

alexpotato 5y ago

Because, IIRC, a lot of neurons are dedicated to motion/sensing. Bigger animals may require more neurons to handle moving larger and/or more complicated muscle groups. Interesting related point there is the encephalization quotient which is related to the predicted ratio of brain size to body mass. On the wikipedia page [0] they list the EQ for various animals. Humans are the highest but dolphins and ravens are not far behind.

molticrystal 5y ago
To further emphasize that having neural material focused on the appropriate functions is more important vs how much you have, here is a story about a guy whose brain is mostly hollow and filled with fluid, it probably did cause his IQ to be 75 and causes him weakness in his legs, but otherwise he lives a normal adult life more or less. https://www.newscientist.com/article/dn12301-man-with-tiny-brain-shocks-doctors/ https://www.newscientist.com/article/dn12301-man-with-tiny-b...
- acchow 5y ago
  Doesn't this demonstrate the opposite of what you were claiming?
  - lacksconfidence 5y ago
    I feel like the quotes agree with parent: > “If something happens very slowly over quite some time, maybe over decades, the different parts of the brain take up functions that would normally be done by the part that is pushed to the side,” adds Muenke, who was not involved in the case.
  - Ajedi32 5y ago
    Did you see the scans? The dude's head is practically empty (brain 55-75% smaller than normal) and nobody even noticed until he was 44 years old and got an MRI.
  - divbzero 5y ago
    I think it’s that a priori you would expect a hollow brain to have a far more drastic effect and not allow for a mostly normal adult life.

btilly 5y ago

How do you measure intelligence? Elephants have much better memories than we do! https://www.scientificamerican.com/article/elephants-never-forget/ https://www.scientificamerican.com/article/elephants-never-f...

Ajedi32 5y ago
That article doesn't seem to support your claim. All of the feats mentioned would be entirely unremarkable in your average human.
- btilly 5y ago
  Really? You'd immediately recognize someone you knew for a few weeks over 20 years ago? You wouldn't need a bit to try to figure out who they are? If so, then your memory is unusually good. I know that this is well beyond my capabilities. Nor do I have the ability to visit a place that I lived 40 years earlier and find my way around.
  - Spooky23 5y ago
    I think it depends on the intensity of the experience. I recently found myself in a hotel that I stayed in as a 7-8 year old in the 80s for a particularly memorable vacation with my extended family. It was funny that I still remembered the I unusual aspects of the layout and could spot many of the changes that had been made over the years. But if you asked me to describe someone I met for a few days in a business context in 2020, I’d have a hard time remembering detail.
  - Someone 5y ago
    How many other elephants did these elephants see in those 20+ years? It wouldn’t surprise me if that was fewer than 100. How many did they spend a few weeks or more with? It wouldn’t surprise me if that were less than 20. There also, AFAIK, isn’t evidence they remember _all_ other elephants they’ve shared time with for at least few weeks (I certainly do not rule that out, either, given the low number they likely will meet in their life)
  - 5y ago

juancn 5y ago

Well, biological neurons are much more complex than CS neurons (https://www.quantamagazine.org/how-computationally-complex-is-a-single-neuron-20210902/ https://www.quantamagazine.org/how-computationally-complex-i...). Also, you're working under the assumption that they are equivalent between mammals which as far as we can tell it's not the case (https://www.medicalnewstoday.com/articles/why-are-human-neurons-different-from-those-of-other-mammals https://www.medicalnewstoday.com/articles/why-are-human-neur...). So my guess is that the comparison is much more complex than just number of neurons.

fabiospampinato 5y ago

I read on wikipedia [0] the other day a fairly disturbing statistic related to this, apparently human men have on average a ~10% bigger brain than women. It'd be interesting to know if that translates to a higher neuron count or the difference in volume is due to something else. [0]: https://en.wikipedia.org/wiki/Brain_size#:~:text=In%20men%20the%20average%20weight%20is%20about%201370%20g%20and%20in%20women%20about%201200%20g https://en.wikipedia.org/wiki/Brain_size#:~:text=In%20men%20....

andrewflnr 5y ago
Probably just a consequence of overall physical size being larger. AFAIK there continues to be no evidence of a sex difference in overall intelligence, so slight difference in brain size is probably a red herring.

gwern 5y ago

Density is also important. If we look at other things - some recent studies have been done on number-counting (https://royalsocietypublishing.org/doi/10.1098/rstb.2020.0529 https://royalsocietypublishing.org/doi/10.1098/rstb.2020.052...) or bird brains (https://www.gwern.net/docs/psychology/neuroscience/2020-herculanohouzel.pdf https://www.gwern.net/docs/psychology/neuroscience/2020-herc...) - density jumps out as a major predictor. African elephants may have some more neurons, but the density isn't as great as a human where it counts, so they are remarkably intelligent (like ravens and crows), but still not human-level. There are diminishing returns in both directions. We have more neurons than any bird as much or more dense, and we have more density than any elephant with as many or more neurons. Put that together, and we squeak across the finish line to being just smart enough to create civilization. An analogy: what's the difference between a supercomputer, and the same number of CPUs scattered across a few datacenters? It's that in a supercomputer, those CPUs are packed physically as close as possible with expensive interconnects to allow them to communicate as fast as possible. (For many applications, the supercomputer will finish long before the spread out nodes ever finish communicating and idling.) But you need to improve both or else your new super-fast CPUs will spend all their time waiting on Infiniband to chug through, or your fancy new Infiniband will be underutilized and you should've bought more CPUs.

user90349032 5y ago
And yet, no animal except humans is self aware. Really makes you wonder why that is.
- stjohnswarts 5y ago
  that is simply incorrect bonobos, orcas, elephants, dolphins, chimpanzees, etc have all shown degrees of self awareness.
  - stjohnswarts 5y ago
    Haha downvoted for stating the obvious and something that can be found in seconds on any google search. Never change HN.

tshaddox 5y ago

For one thing, when the article says "bigger" it means "more parameters," not "more neurons."

urthor 5y ago

If neural networks have shown us anything, it's that not all neurons are born the same. After all, even in nature there are multiple types of neurons. I imagine it's 100% dependent on the cardinal rule of neural networks: "Choice of training data is 10 times more important than the actual model." What we have over elephants are opposable thumbs, excellent eyes, and vocal cords. And crucially, we're generally speaking pretty slow, weak and useless. Except for our elaborate methods of I/O. Our entire success is based on a feedback loop. "If human uses their IO this way, human will get more food." Thus, we become ever more sophisticated at this. We are nothing if not a vehicle for using our high dexterity, low gross force, opposable thumbs in inventive ways to get food. Plus, we have a biological imperative to pass these techniques on as knowledge. A baby elephant can probably feed itself by eating green stuff at 1 year old (I know nothing about elephants). A human child realistically cannot independently scrounge up enough solid food to sustain themselves, until they're what, twelve? Twenty-two? Certainly no younger than eight. We have, almost certainly, the most useless progeny in the animal kingdom. Hence we invest an enormous amount of time and energy in education to make them able to feed themselves. So the tl;dr is 1) Human brains are pretty similar to the animal kingdom's. 2) Human opposable thumbs are world class. Pretty close to as good as it gets. Sight is also top notch, many animals have useless eyeballs. 3) Most human food is obtained by doing creative things with thumbs. This is very complex, and takes a lot of practice. 4) Human birth the most useless children in the entire animal kingdom. These children take decades to fully grow, hence we invest an enormous amount of time educating them in opposable thumbs. 5) Over time our education system gets better and better, and our list of clever things we can do with opposable thumbs get longer and longer. Essentially what we have over the other animals isn't neurons. What we have over the other animals is a data collection/cleaning/utilization cycle.

raxxorrax 5y ago

But only 1/3 as much in their cerebral cortex. Maybe having a multi purpose trunk does bind a lot of capacity?