Evolution of the human brain: when bigger is better

[extherian]

This article (click HERE) on the relationship between brain size and intelligence could be very interesting for any discussion on Superbrights.

[Matterplay1]

This article (click HERE) on the relationship between brain size and intelligence could be very interesting for any discussion on Superbrights.

I read an article in Scientific American a while back that made some similar points. Will hunt through my back issues and see if I can find something to point to.

[extherian]

The article's conclusion is that increasing brain size hits rapidly diminishing returns beyond a doubling of capacity. This has serious implications for the Highbrows, who apparently have a brain ten times the normal size!

To be fair to AI Vin, he does specify that the Highbrow brain isn't structured in exactly the same way as the standard human brain, with an extra layer of the cerebral cortex folding over the two hemispheres.

Nonetheless, his design still runs into the same latency issues that would occur in real life. Large parts of the Highbrow brain are located in the abdomen, which would massively increase communications lag between different parts of the brain and diminish the benefits of all that extra neural tissue.

[stevebowers]

A purely biont Superior with a biological nervous system would run into latency problems, just like a matrioshka brain without an internal wormhole bus. I think we would just have to accept that a big-brained biont would be a bit slow when using eir entire processing capacity. Of course this connectivity could be accelerated artificially by using cybernetic enhancements, such as an exocortex (which would presumably include its own high speed connectome).

I would expect a Gaian Whale or a Sufant to be a bit... leisurely.. to talk to, because of their large brains, although they might be capable of quick responses on occasion.

[extherian]

I said much the same thing in my article on the Yas Om. They are in fact slower thinkers than a typical Superior, but benefit from being able to consider things from a truly huge number of different perspectives at once to compensate. In fact, their incredible multitasking and mental flexibility make them resemble a Superturing AI rather than any kind of normal biont.

But the Yas Om have a brain that was designed from the ground up to be decentralised, so it scales much better with increasing mass than a human brain would. The Highbrows, on the other hand, would face additional challenges other than just worse latency.

I don't know how much of the linked article you read, but there's a chart (click HERE) describing how the subcortical volume begins decreasing as a percentage of total brain volume with increasing size. In other words, areas like the hippocampus, crucial for memory formation, and the amygdala, involved in the subjective experience of emotions, would shrink in proportion to the rest of the brain as it increased in size.

These issues could have serious consequences for a being with a 14 kg brain. Consider that at just 9kg, the brain would consist entirely of white and grey matter, with no subcortical areas at all! So no amygdala, hippocampus, etc. Of course this could be managed with cybernetic implants, but presumably a being that cultivated such a massive brain would prefer to be able to rely on their biological tissue alone. After all, they must have a bioist outlook or they would simply have become uploads and could scale to as much 'brain tissue' (i.e. drytech computronium) as they pleased.

Whales and elephants wouldn't encounter these problems as their brains have a different structure. Much larger proportions of their brains are devoted to the cerebellum as a consequence of having such a massive body to manipulate.

[Drashner1]

It seems reasonable to me that someone seeking to engineer a sophont with a larger bio-brain would eventually run into some point of diminishing returns or 'you just can't get there from here' situation that would require either a more direct redesign of the brain. This might involve a different overall structure analogous to Extherian's mention of elephants and whales having different brain structures, or the introduction of 'bio-augmentics' such as (for example) biologically grown brain structures making use of conductive elements to move signals closer to electronic speeds or 'bio-fiber optics' or other light based methods to move signals at closer to optical speeds. IIRC we make some mention of this sort of thing in the Silk God article, but less advanced versions (comparatively speaking) would likely be in the metaphorical toolbox of sophonts interested in this kind of thing for thousands of years beforehand.

My 2c worth,

Todd

[Matterplay1]

Of course, we baseline humans (and probably the other big-brained animals too) are already into latency issues. When you reach for something, your hand is already in motion some fractions of a second before 'headquarters' - the part of you that monitors what you are up to overall - is aware that the decision has already been made. Some people have argued on this basis that 'free will' doesn't exist, but that's not quite right. It's just that your brain is somewhat democratic and gives a bit of local autonomy (to put it in political terms). "You" are already a collective, with collective decisions and local decisions going on all the time.

This goes back to those Superiors, and other high intelligence beings in the OA setting being possibly quite competent to deal with matters quite quickly and efficiently without bringing their entire intellect to bear on a problem. At the extreme, OA's archailects may have very significant delays in their internal workings but still be lightning-quick (or quicker) responding to whatever they need to deal with that isn't a problem on the order of understanding another archailect.

[stevebowers]

Of course this could be managed with cybernetic implants, but presumably a being that cultivated such a massive brain would prefer to be able to rely on their biological tissue alone. After all, they must have a bioist outlook or they would simply have become uploads and could scale to as much 'brain tissue' (i.e. drytech computronium) as they pleased.

I'm coming to believe that biological enhancements wouldn't be enough in many cases. Superior-level humans would benefit from neurotech enhancements to speed up their connectome; vacuum-adapted humans would benefit from additional respiration equipment to allow them to remain in vacuum longer, or even indefinitely; merpeople would benefit from additional oxygen reservoirs and external fins/flippers to wear, and so on. The best use of genetic engineering in many cases would be to help the sophont interface with artificial augmentations that an unaltered baseline could not utilise efficiently. In the past I've called this concept 'cybertweaking'- the genetic modification of an organism so that it can interface better with technology. But maybe that is a topic outside the scope of this discussion.

[extherian]

In the case of Highbrows, absolutely, they would benefit a great deal from incorporating neurotech into their brain design. So too would beings with multiple brains like the Cyborn or the Yas Om.

However, I doubt this would be necessary for 'normal' Superiors. Improved pattern recognition, memory and observation could be accomplished with improvements to the brain's underlying connectivity. There are people in real life with incredible capabilities in these areas, who were lucky enough to born with their brains wired up in an unusual way. Sleep and multitasking improvements would require more drastic changes to the brain's structure, but I think they could be accomplished without external aids.

[ai_vin]

The article's conclusion is that increasing brain size hits rapidly diminishing returns beyond a doubling of capacity. This has serious implications for the Highbrows, who apparently have a brain ten times the normal size!

To be fair to AI Vin, he does specify that the Highbrow brain isn't structured in exactly the same way as the standard human brain, with an extra layer of the cerebral cortex folding over the two hemispheres.

Nonetheless, his design still runs into the same latency issues that would occur in real life. Large parts of the Highbrow brain are located in the abdomen, which would massively increase communications lag between different parts of the brain and diminish the benefits of all that extra neural tissue.

Guys, I did consider the latency issue when I did the Highbrows. In the article there is this line: This enlarged neural network needs an expanded capacity for data traffic control and to do this an extension of the cerebellum has wrapped itself around the spinal cord and continued to grow down the enlarged vertebral canal. From there it can link up with and manage the workings of the grey matter in the vertebral tube.

Not knowing a lot about how the brain works I left a lot of the details to the imagination but I figure the extension of the cerebellum in the spinal cord could handle latency by speeding up some signals and slowing others.