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Comment by prerok | Hacker News Reader

I remember reading an article in National Geographic of how crow's brains are much more interconnected than is the norm in mammals, i.e. IIRC they have a higher density of synapses between neurons. From that article, it seems that the usual brain weight vs. body weight to determine intelligence, which seems can be used to approximate intelligence in different species of mammals, cannot be used for birds (or at least crows, which the article was focusing on).

In other words, they seem to achieve better results with smaller brains than we thought. And yes, crows (in EU) do exhibit some pretty intelligent behavior.

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The brains of corvids are not closely related to mammalian brains. All the mammals have roughly the same brain, but corvids have a different architecture.[1]

Intelligence seems to have evolved three times on this planet - mammals, corvids, and octopuses. Octopuses have a distributed system rather than one central brain. They all have neurons, but the higher level architecture differs drastically.

Knowing that several different architectures can work is important for AI. There's apparently more than one way to do it.

[1] https://www.sciencedirect.com/science/article/abs/pii/S23521...

Where do parrots fall in this grouping? They're not corvids. There must have been a pre-corvid ancestor.

Parrots aren't evil, they're just assholes.

Octopuses are probably more alien than others.

My point here is that if intelligence developed more than once, it didn't come from some one-time random event or divine intervention. It looks like once there are connected neurons, it evolves via continuous improvement.

In some environments, that evolution hits limits. Flying birds are limited in brain mass or they can't get airborne. Which may be why corvids don't rule the world.

Oh yes absolutely. Intelligence certainly developed more than once. Bird brain is no slur.

Before your comment I would have said it emerged twice, but then I had not considered octopuses, they are wicked smart and so unlike other intelligent animals we know.

I appreciate the linked article. I wonder if the the list should be expanded to 'at least three times', and I start to think about intelligence in plants.

See also recent work on honeybees, popularized here https://www.smithsonianmag.com/smart-news/bumblebees-can-sol...

honeybees are not social insects, but maybe social insects should be added to the list?

Social insects. The original object oriented programming paradigm.

I've read there's also a social aspect - crows are extremely social creatures, as are humans, and other highly intelligent animals like whales. That does seem to be a common denominator.

Regarding that, I'm reminded of another story - on my daily walk near work, there was a dead crow on the pavement. 5 or so crows were standing all around it, doing nothing really. Even me passing close by did not trigger them to fly away or anything, it seemed like they were standing watch on the body. The next day, it was still there, same thing. The 3rd day, it was gone, but the crows were still standing watch in the same manner. I didn't know what to make of it other than it appeared they were mourning or taking part in some type of ingroup ritual. I didn't see it again after that, but it struck me.

> [Social creatures] does seem to be a common denominator.

One theory is that it drives the creatures to internally model or simulate others intents and reactions, in a way which is a far more regular, consistent, and nuanced than any modeling of various prey or predators.

Further along that path is modeling future-me in plans, and layers of "I know they will know I know they know, so..."

Corvids have been known to investigate deaths, truly fascinating creatures!

https://www.sciencedirect.com/science/article/abs/pii/S00033...

Thanks for linking this, I had been wondering what the heck I had observed. It was really interesting. I love watching them. I almost always see something new (for me)

Thanks for the link. I observed a flock of "mourning" crows around a dead one in the field behind my yard. I was flabbergasted at what I was seeing. So they are mourning and investigating the cause of death for the sake of the flock. Wow!

I'm not an expert in the area but have read a bunch on this topic to try and understand it better. Bird brains and human brains are structured very differently. Birds are much more like GPUs with independent distributed processing happening in parallel. Mammals have these big bidirectional layers where signals are constantly propagating up and down in a big connected computation.

I wonder what the energy/evolutionary cost of densely-connected brains is. If it's advantageous, why are crows exceptional?

Maybe they require the equivalent of advanced EUV machines to make?

It could simply be an evolutionary "discovery", with no particular advantage over our "brain model". Evolution doesn't seek out optima; it simply encourages genetic structures that improve odds of reproductive success.

Or, to put it another way: if corvid genetics happened upon a brain type that promoted their survival, it doesn't matter if it was "better" or "worse" than the path the monkey/hominid brains took. Genetics took the first bus going in that direction.

In terms of why bird brains would be exceptionally efficient for their volume (and I assume by extension, mass), would be that weight is at a premium for them.

Another case of brain efficiency : jumping spiders. They have less than half of ant's neurons, but instead of bruteforcing computing power they have a different specialized wirings.

This might be what that article referred to [0]?

tl;dr, the higher cognitive abilities of birds are centered in a different region of the brain compared to mammals, the pallium vs the cortex. Neuron density in the bird pallium is also higher than the comparable density in the mammalian cortex.

[0] Developmental origins and evolution of pallial cell types and structures in birds https://www.science.org/doi/10.1126/science.adp5182

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