Bigger brains are not always better

Humans can also work fine with almost no brain tissue, as has been discovered throughout history. The canonical article is from 1980, "Is Your Brain Really Necessary?"[0]

"There's a young student at this university," says Lorber, "who has an IQ of 126, has gained a first-class honors degree in mathematics, and is socially completely normal. And yet the boy has virtually no brain." The student's physician at the university noticed that the youth had a slightly larger than normal head, and so referred him to Lorber, simply out of interest. "When we did a brain scan on him," Lorber recalls, "we saw that instead of the normal 4.5-centimeter thickness of brain tissue between the ventricles and the cortical surface, there was just a thin layer of mantle measuring a millimeter or so. His cranium is filled mainly with cerebrospinal fluid."

[0] http://www.rifters.com/real/articles/Science_No-Brain.pdf

Sure absolute size doesn't matter. But what about number of neurons or neural connections? I'd be curious what the actual studies say.

The article hinted at this: "African gray parrots, which can identify shapes and even count, as well as corvids, which have an equivalent number of neurons to some primates and, it is suggested, may even be self-aware."

Comparing brain size vs intelligence across species seems weird since neuron size/density differs so much.

It is not about how big the brain is. It is about the number of neurons, latency, signal reliability and number of connections.

Voltage-gated ion channels are non-deterministic. Meaning they don't always open (or not open) when they should. In order to stuff more neurons into the same volume of space, you have to shrink them. The problem is, those ion-channels become more and more unreliable as the size decreases. I would argue that they're already too unreliable in many humans.

Second problem, as the size of the axon and myelin sheath decrease, signal reliability and latency will suffer. Yes, the current can die out part-way to its destination. As the brain is less globally connected due to the sheer lack of space, poor signal reliability and increased latency, it will begin to favor local connections over global ones. In other words, specialization and usage of signal superhighways to compensate, just like a crowded city. The problem with a crowded city is, even with great public transport, many people never leave their neighborhoods.

So what to do about it? You can leave neurons the same size and make more room instead of trying to shrink them.

First problem with this, difficulty of childbirth due to skull size. Second, increased development time, it's already too long as it is. Third, latency and signal reliability will still suffer due to increased distance. Fourth, increased use of resource. You also need to support those neurons and that support system will eat up more and more space.

If you try to blow up the size of the axon and myelin sheath to fix the latency and reliability problems, it will eat up even more space. In other words, less room for neurons and you're back to square one. Another problem is, you need a bigger body to support that huge brain. More neurons will be dedicated to processing touch instead of higher-level abstract thoughts.

One last thing you can try is, decrease body size, increase brain volume slightly. The lower level of violence, abundance of food, modern healthcare (c-section) and longer lifespan (more time to mature) in modern human societies allow us to do this already. Dedicate more resource to higher levels of the brain associated with abstract thoughts, planning, reasoning, etc. Over-myelinate those areas to increase signal speed and reliability.

At the end of the day, there's not much more mother nature can do without deep structural and material change. Reengineer the myelin materials to increase their insulating property and decrease the size. Make the ion-channels more reliable so you can shrink neurons even more, although you still have to worry about quantum tunneling. Or better yet, do away with ions completely and switch to photonic computing.

I'd like to suggest a theory here, that a brain's primary function is to study and occasionally override the information processing algorithms contained in the "unconscious" DNA of the organism. Once the brain has discovered the optimal solution through innovative overrides, the best behavioral solutions are recorded and automated in the DNA as hard code, and no longer requires either supervision or further revisions. At that point in the evolutionary history of the species, it no longer needs to invest so much energy in maintaining such a large a brain, now that what amounts to optimal "muscle memory" in the DNA has been established through successful survival and selection of repeating behavior patterns. So what may appear to us be highly intelligent behavior, these functions are coming not from the brain, but from what has been captured in the DNA. This is a theory from a novice, I am not a scientist of any kind, but an entrepreneur. I don't have time or resources to research the validity of this theory, but perhaps someone else does? Thank you.

"Eberhard used these web-making mistakes as a proxy for cognitive capacity."

That line seems kind of suspect from my armchair. Web-making isn't a general behavior, and could probably be assigned a certain optimal ammount of brain space as sight and other tasks were compromised to make room in smaller brains. How did the researchers deal with this?

There is a great statistic called the encephalization quotient that is simply log brain mass divided by log body mass. There is a fairly strong correlation (https://universe-review.ca/I10-83-brainmass.jpg), but you find that species which deviate from the best fit line (biggest residuals) tend to be the species we associate as intelligent or not intelligent. Humans have the largest magnitude residual.

Now that we have deep learning, we know that more layers don't always give better results. Perhaps intelligence and wit is obtained when associations allow our mind to develop neurons that are useful for modeling interesting features. For example, being good at math and having good reasoning skills are very useful features that can be acquired by education and practice. Also we now know that our brain in much more plastic that what was previously believed, for example taxi drivers brains have a bigger spatial area as a result of learning to around big cities. So the question to get better intelligence is how we make child brains develop neural systems related to useful features?, unfortunately teaching chess is not a solution, but perhaps is a step in the right direction, more research is needed.

That complex behaviors can arise from simple processes is understood. Moreover in the species mentioned in the article, the problem spaces relevant to survival may have been relatively stable for untold amounts of time. The stable problem spaces increase the evolutionary fitness of efficient algorithms that solve that problem space with min energy expenditure. But such efficiency usually has a cost: reduced flexibility to changes in the problem space. I submit to you that behavioral flexibility in new environments may well correlate with brain size, even excluding humans from the analysis.

I remember seeing a photograph of Quentin Tarantino shaking hands with his producer and thinking: the craniums on these guys are enormous. It was the first time I realized consciously that when I look at people with large craniums I do automatically assume they are smarter.

Since I realized that, I reserve judgement until they start talking.

I read an interesting article a while ago about a Russian scientist Dmitry Belyayev who did an experiment to try to domesticate wild foxes through selective breeding (by selecting the most docile specimens for reproduction) and the foxs' heads (and presumably brain) shrunk as their became more domesticated (source: https://www.pelicanbooks.com/the-domesticated-brain/preface).

I have a theory that it's the same with people - It would be interesting to do studies. It's well documented that Neanderthals had larger heads/brains than Cro-Magnons.

When I learned that humans have genetic mutations resulting in an additional chromosome, my first reaction was to associate it with something like "X-Men" and a big time advantage, and then finding out that it's pretty much an undesirable development complication, I learned a lot about my assumptions + imagination versus finding out the real story.

> The best chip out of Intel can’t fly, ... , can’t dogfight,

It can https://www.google.pl/amp/www.popsci.com/amp/ai-pilot-beats-...

Neanderthals had bigger brains than us

Whale brains are absolutely enormous but I don't see them doing quantum field theory.

for example women have smaller but denser brains with closer neurons. so no bigger isn't always better.

We'd be better off with much smaller brains, so that we can have smaller heads optimized for an aquatic life. We're failing pretty miserably at this civilization stuff anyway.

I read somewhere that ants design better algorithms than humans;