jacob_cannell comments on Steelmaning AI risk critiques - Less Wrong
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Yes, I've read your big universal learner post, and I'm not convinced. This does seem to be the crux of our disagreement, so let me take some time to rebut:
First off, you're seriously misrepresenting the success of deep learning as support for your thesis. Deep learning algorithms are extremely powerful, and probably have a role to play in building AGI, but they aren't the end-all, be-all of AI research. For starters, modern deep learning systems are absolutely fine-tuned to the task at hand. You say that they have only "a small number of hyperparameters." which is something of a misrepresentation. There are actually quite a few of these hyperparameters in state-of-the-art networks, and there are more in networks tackling more difficult tasks.
Tuning these hyperparameters is hard enough that only a small number of researchers can do it well enough to achieve state of the art results. We do not use the same network for image recognition and audio processing, because that wouldn't work very well.
We tune the architecture of deep learning systems to the task at hand. Presumably, if we can garner benefits from doing that, evolution has an incentive to do the same. There's a core, simple algorithm at work, but targeted to specific tasks. Evolution has no incentive to produce a clean design if cludgy tweaks give better results. You argue that evolution has a bias against complexity, but that certainly hasn't stopped other organs from developing complex structure to make them marginally better at the task.
There's also the point that there's plenty of tasks that deep learning methods can't solve yet (like how to store long-term memories of a complex and partially observed system in an efficient manner) - not to mention higher level cognitive skills that we have no clue how to approach.
Nobody thinks this stuff is just a question of throwing yet larger deep learning networks at the problem. They will be solved by finding different hard-wired network architectures that make the problem more manageable by knowing things about it in advance.
The ferret brain rewiring result is not a slam-dunk for the universal learning by itself. It just means that different brain modules can switch which pre-programmed neural algorithms they implement on the fly. Which makes sense, because on some level these things have to be self-organizing in the first place to be compactly genetically coded.
The real test here would be to take a brain and give it an entirely new sense - something that bears no resemblance to any sense it or any of its ancestors has ever had, and see if it can use that sense as naturally as hearing or vision. Personally, I doubt it. Humans can learn echolocation, but they can't learn echolocation the way bats and dolphins can learn echolocation - and echolocation bears a fair degree of resemblance to other tasks that humans already have specialized networks for (like pinpointing the location of a sound in space).
Notably, the general learner hypothesis does not explain why non-surgically-modified brains are so standardized in structure and functional layout. Something that you yourself bring up in your article.
It also does not explain why birds are better at language tasks than cats. Cat brains are much larger. The training rewards in the lab are the same. And, yet, cats significantly underperform parrots at every single language-related task we can come up with. Why? Because the parrots have had a greater evolutionary pressure to be good at language-style tasks - and, as a result, they have evolved task-specific neurological algorithms to make it easier.
Also, plenty of mammals, fresh out of the womb, have complex behaviors and vocalizations. Humans are something of an outlier, due to being born premature by mammal standards. If mammal brains are 99% universal learning, why can baby cows walk within minutes of birth?
Look, obviously, to some degree, both things are true. The brain is capable of general learning to some degree. Otherwise, we'd never have developed math. It also obviously has hard-coded specialized modules, to some degree, which is why (for example) all human cultures develop language and music, which isn't something you'd expect if we were all starting from zero. The question is which aspect dominates brain performance. You're proposing an extreme swing to one end of the possibility space that doesn't seem even remotely plausible - and then you'e using that assumption as evidence that no non-brain-like intelligence can exist.
What about Watson? It's the best-performing NLP system ever made, and it's absolutely a "weird mathy program." It uses neural networks as subroutines, but the architecture of the whole bears no resemblance to the human brain. It's not a simple universal learning algorithm. If you gave a single deep neural network access to the same computational resources, it would underperform Watson. That seems like a pretty tough pill to swallow if 'simple universal learner' is all there is to intelligence.
Finally, I don't have the background to refute your argument on the efficiency of the brain (although I know clever people who do who disagree with you). But, taking it as a given that you're right, it sounds like you're assuming all future AIs will draw the same amount of power as a real brain and fit in the same spatial footprint. Well... what if they didn't? What if the AI brain is the size of a fridge and cooled with LN2 and consumes as much power as a city block? Surely at the physical limits of computation you believe in, that would be able to beat the pants off little old us.
To sum up: yes, I've read your thing. No, it's not as convincing as you seem to believe.
Cat brains are much larger, but physical size is irrelevant. What matters is neuron/synapse count.
According to my ULM theory - the most likely explanation for the superior learning ability of parrots is a larger number of neurons/synapses in their general learning modules - (whatever the equivalent of the cortex is in birds) and thus more computational power available for general learning.
Stop right now, and consider this bet - I will bet that parrots have more neurons/synapses in their cortex-equivalent brain regions than cats.
Now a little google searching leads to this blog article which summarizes this recent research - Complex brains for complex cognition - neuronal scaling rules for bird brains,
From the abstract:
The telencephalon is believed to be the equivalent of the cortex in birds. The cortex of the smallest monkeys have about 400 million neurons, whereas the cat's cortex has about 300 million neurons. A medium sized monkey such as a night monkey has more than 1 billion cortical neurons.
Interesting! I didn't know that, and that makes a lot of sense.
If I were to restate my objection more strongly, I'd say that parrots also seem to exceed chimps in language capabilities (chimps having six billion cortical neurons). The reason I didn't bring this up originally is that chimp language research is a horrible, horrible field full of a lot of bad science, so it's difficult to be too confident in that result.
Plenty of people will tell you that signing chimps are just as capable as Alex the parrot - they just need a little bit of interpretation from the handler, and get too nervous to perform well when the handler isn't working with them. Personally, I think that sounds a lot like why psychics suddenly stop working when James Randi shows up, but obviously the situation is a little more complicated.
I'd strongly suggest the movie project nim, if you haven't seen it. In some respects chimpanzee intelligence develops faster than that of a human child, but it also planes off much earlier. Their childhood development period is much shorter.
To first approximation, general intelligence in animals can be predicted by number of neurons/synapses in general learning modules, but this isn't the only factor. I don't have an exact figure, but that poster article suggests parrots have perhaps 1-3 billion ish cortical neuron equivalent.
The next most important factor is probably degree of neotany or learning window. Human intelligence develops over the span of 20 years. Parrots seem exceptional in terms of lifespan and are thus perhaps more human like - where they maintain a childlike state for much longer. We know from machine learning that the 'learning rate' is a super important hyperparameter - learning faster has a huge advantage, but if you learn too fast you get inferior long term results for your capacity. Learning slowly is obviously more costly, but it can generate more efficient circuits in the long term.
I inferred/guessed that parrots have very long neotenic learning windows, and the articles on Alex seem to confirm this.
Alex reached a vocabulary of about 100 words by age 29, a few year's before his untimely death. The trainer - Irene Pepperberg - claims that Alex was still learning and had not reached peak capability. She rated Alex's intelligence as roughly equivalent to that of a 5 year old. This about makes sense if the parrot has roughly 1/6th our number of cortical neurons, but has similar learning efficiency and long learning window.
To really compare chimp vs parrot learning ability, we'd need more than a handful of samples. There is also a large selection effect here - because parrots make reasonably good pets, whereas chimps are terrible dangerous pets. So we haven't tested chimps as much. Alex is more likely to be a very bright parrot, whereas the handful of chimps we have tested are more likely to be average.
Not much to add here, except that it's unlikely that Alex is an exceptional example of a parrot. The researcher purchased him from a pet store at random to try to eliminate that objection.
This is curious. I wonder if bird brains are also more energy efficient as a result of the greater neuronal densities (since that implies shorter wires). According to Ratio of central nervous system to body metabolism in vertebrates: its constancy and functional basis the metabolism of the brain of Corvus sp (unknown species of genus Corvus, which includes the ravens) is 0.52 cm^3 O2/min whereas the metabolism of the brain of a macaque monkey is 3.4 cm^3 O2/min. Presumably the macaque monkey has more non-cortical neurons which account for some the difference, but this still seems impressive if the Corvus sp and macaque monkey have a similar number of telencephalic/cortical neurons (1.4B for the macaque according to this paper). Unfortunately I can't find the full paper of the abstract you linked to to check the details.
Yes - that seems to be the point of that poster I found earlier.
From an evolutionary point of view it makes sense - birds are under tremendous optimization pressure for mass efficiency. Hummingbirds are a great example of how far evolution can push flight and weight efficiency.
Primate/human brains also appear to have more density optimization than say elephants or cetaceans, but it is interesting that birds are even so much more density efficient. Presumably there are some other tradeoffs - perhaps the bird brain design is too hot to scale up to large sizes, and uses too much resources, etc.
It was a recent poster - so perhaps it is still a paper in progress? They claim to have ran the defractionator experiments on bird brains, so they should have estimates of the actual neuron counts to back up their general claims, but they didn't provide those in the abstract. Perhaps the data exists somewhere as an image from the actual presentation. Oh well.