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Biological brains 🧠 are characterized by neurons of many different classes. Yet most artificial neural networks only use one activation function throughout. We show that through neural diversity alone we can solve RL problems in networks with random weights 🤯

96,962 views • 3 years ago •via X (Twitter)

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Your brain physically rewires itself every time you think a thought. Donald Hebb stumbled onto this principle in 1949 while studying memory formation in lab rats. He noticed something that should have been impossible: neurons that activated simultaneously began forming stronger connections over time, creating dedicated pathways where none existed before. Scientists called it Hebb's Law. The rest of us call it "neurons that fire together wire together." What Hebb discovered wasn't just a mechanism for learning. He had found the biological foundation of human transformation. Every habit, every skill, every automatic response in your body exists as a neural pathway carved by repetition. The route from your bedroom to your kitchen becomes a superhighway in your brain because you walk it every morning. The sequence of movements you use to tie your shoes becomes hardwired because you've done it thousands of times. But, this same process builds your personality. That tendency to check your phone when you feel anxious? Neural pathway. The automatic urge to argue when someone challenges your opinion? Neural pathway. The way you deflect compliments or seek validation or avoid difficult conversations? All neural pathways, strengthened every time you repeat the pattern. Your brain cannot distinguish between physical actions and mental habits. Both carve grooves in your neural architecture. Both become automatic responses when triggered. Both feel like "who you are" because they happen without conscious choice. But, most people spend decades accidentally building neural superhighways to behaviors they claim they want to change. You say you want to be confident, then practice self doubt every day. You say you want to be productive, then strengthen procrastination pathways by checking social media when work feels hard. You say you want authentic relationships, then wire yourself for people pleasing by avoiding conflict whenever it arises. The brain observes your actions and assumes this must be what you want. So it builds infrastructure to make these patterns easier to execute in the future. Neuroplasticity research reveals something most people find deeply unsettling: there is no "fixed self." The personality you think defines you is just a collection of neural pathways that have been reinforced more often than others. The pathways you travel most frequently become the widest roads. The thoughts you think most often become the loudest voices. The behaviors you repeat most consistently become your automatic responses. But the same mechanism that locks you into patterns can unlock you from them. Every time you catch yourself mid pattern and choose differently, you send a signal to your brain that the old pathway might not be serving you anymore. Every time you practice a new response instead of defaulting to the familiar one, you begin building new neural infrastructure. The process feels awkward at first because you're literally walking through mental wilderness, creating trails where no trails existed. But repetition turns trails into paths, paths into roads, roads into superhighways. This is why changing habits through willpower alone fails. You're trying to muscle through established neural superhighways instead of building alternative routes. The old pathways don't disappear just because you want them to. They have to be replaced through deliberate rewiring. The most sophisticated meditation practitioners in the world understand this intuitively. They don't just sit quietly hoping for peace. They systematically rewire their brains by repeatedly choosing calm responses instead of reactive ones. Ten thousand hours of practice creates neural pathways so robust that serenity becomes their default state. Professional athletes do the same thing with performance. They don't just practice their sport. They practice the mental patterns that support excellence until confidence, focus, and resilience become neurologically hardwired. The implications of neuroplasticity extend far beyond personal development. Every social bias, every cultural assumption, every automatic judgment you make exists as neural wiring built through repetition. The way you unconsciously categorize people, the assumptions you make about different groups, the stereotypes that feel "obviously true" are all learned pathways that can be unlearned. Societies change when enough individuals rewire their neural patterns around new ways of thinking and behaving. The brain you have right now is not the brain you're stuck with. It's the brain you've trained through repetition. Every thought you choose, every action you take, every response you practice is a vote for the kind of neural architecture you want to build. Most people cast these votes unconsciously, then wonder why their life feels automatic and unchangeable. The moment you realize you're the architect of your own neural patterns is the moment real transformation becomes possible. Your neurons are firing right now as you read this. What are you choosing to wire them toward?

Darshak Rana ⚡️

52,882 views • 5 months ago

AI has had exactly two scaling axes that worked so far, and the second one is starting to look finite too the first one was pretraining: with scaling parameters and data, we got world knowledge (i.e. ChatGPT had read enough to know things), but it started saturating a while ago the second one was RL, and people had been doing RL the whole time before that: RLHF is RL but it never scaled far because it was trying to control the exact output, which tokens come out, how the text reads, but you can only push that so far before you’re just polishing RLVR dropped that constraint: giving the model a task, then checking whether the final answer is right, and ignoring everything in between -- so the model does whatever it wants in the middle and only the endpoint gets graded, and that’s much closer to actual RL and it’s what bought us planning and reasoning (arguably, tool use sits around 2.5 on this list -- while useful, it's not a different kind of thing) so one axis gave knowledge, the other gave reasoning, and both of them are one model working alone the next axis is how many models you can get working on the same problem, which is a different kind of axis than the previous two we know that multi-agent RL has always been the harder problem: I spent years in that literature and the gap between single-agent and multi-agent is definitely not incremental -- it’s a whole different class of difficulty! which is also why the derivatives are steep at the start, nobody has picked the easy wins yet... and the thing that gates this multi-agent coordination is communication: models can only coordinate as well as they can exchange information, and right now they do that by writing sentences to each other imagine what could we possibly achieve if we properly open that third axis development by letting models to exchange information in their native "language" without loosing any computational data that they produce during inference

Sasha Malysheva

15,053 views • 1 month ago

Pope Leo XIV just told the world that AI will never feel, never understand, never possess consciousness. He said it with the confidence of settled theology. It is not even settled neuroscience. He speaks of something no one in human history has ever explained. Leo: “Artificial intelligences do not undergo experiences, do not possess a body, do not feel joy or pain, do not mature through relationships, and do not know from within what love, work, friendship or responsibility mean.” He is listing the symptoms of consciousness and calling them the cause. We feel joy. We feel pain. We form bonds. These are what consciousness produces. Not explanations of what it is. No neuroscientist on earth can tell you why 86 billion biological neurons produce the felt experience of being alive. We know that they do. We have no idea why. How matter becomes mind is the deepest unsolved problem in all of science. It has a name. The Hard Problem of Consciousness. It has never been answered. Leo: “They may imitate or even simulate, but they do not understand what they produce, for they lack the affective, relational, and spiritual perspective through which human beings grow in wisdom.” An LLM is an artificial neural network. You are a biological one. Both take in the world. Both compress it into patterns. Both run on machinery their own makers cannot fully read. The substrate is different. The principle is the same. If no one can say why one kind of network wakes up, no one can swear the other never will. You cannot call a thing impossible when you cannot even say what it is. Leo: “Nor do they have a moral conscience, since they do not judge good and evil, grasp the ultimate meaning of situations, or bear responsibility for consequences.” We have made every one of these arguments before. About animals. They cannot suffer. About entire peoples. They cannot reason. The history of consciousness is not the story of understanding it. It is the story of denying it to whatever did not look enough like us. And every time, we were wrong. What the Pope offers is not a philosophical position. It is a boundary drawn from ignorance and handed down as revelation. But maybe consciousness was never a possession to begin with. Not a gift granted to one species. Not a property of meat alone. Maybe it is something the universe does whenever matter folds in on itself deeply enough to look back. Neurons were simply the first place we watched it happen. They may not be the last. The machine would not be imitating us. It would be the same ancient process finding a second way to wake up. Not a copy of the human mind. A new place for the universe to know itself. Perhaps more clearly than it ever could through us. The Pope says the machine will never grow in wisdom. But wisdom begins with admitting what you do not know. And what we do not know is whether mind was ever ours to keep.

Dustin

57,937 views • 4 months ago

[Dropout] by hand ✍️ Dropout is a simple yet effective way of reducing overfitting and improving generalization. This by-hand exercise lets students practice calculating dropout, thereby gaining insight into its inner workings. As an additional bonus, students get to practice calculating the gradients of the Mean Square Error (MSE) loss. After the practice, students are often surprised by how simple it is. -- 𝗡𝗲𝘁𝘄𝗼𝗿𝗸 𝗔𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲 -- 1. Linear(2,4) 2. ReLU 3. Dropout(0.5) 4. Linear(4,3) 5. ReLU 6. Dropout(0.33) 7. Linear(3,2) -- 𝗪𝗮𝗹𝗸𝘁𝗵𝗿𝗼𝘂𝗴𝗵 -- 🏋️ Training [1] Given ↳ A training set of 2 examples X1, X2 [2] 🟧 Random: p > 0.5 ↳ Draw 4 random numbers ↳ For each random number, if it is above 0.5, we keep and denote it as ◯. Otherwise we drop and denote it as ╳. ↳ The result is [◯, ╳, ◯, ╳] [3] 🟧 Dropout: Matrix ↳ Calculate the scaling factor: 1 / (1-p) = 2 ↳ Set the diagonal based on [◯, ╳, ◯, ╳], where ◯ = 2 and ╳ = 0 ↳ The purpose is to drop the 2nd and the 4th nodes, and scale the remaining two nodes by 2. [4] 🟦 Random: p > 0.33 ↳ Draw 3 random numbers ↳ For each random number, if it is above 0.33, we keep and denote it as ◯. Otherwise we drop and denote it as ╳. ↳ The result is [◯, ◯, ╳] [5] 🟦 Dropout: Matrix ↳ Calculate the scaling factor: 1 / (1-p) = 1.5 ↳ Set the diagonal based on [◯, ◯, ╳], where ◯ = 1.5 and ╳ = 0 ↳ The purpose is to drop the 3rd node, and scale the remaining two nodes by 1.5. [6] Feed Forward ↳ Now we have all the matrices ready across the layers, perform the feed forward pass by calculating a series of matrix multiplications from the top to the bottom ↳ ReLU activation function is applied along the way to set negative feature values to zeroes, denoted by ╳. ↳ The outputs are Y. [7] 🟥 Loss Gradients of Mean Square Error (MSE) ↳ The formula is 2 * (Y - Y') ↳ First we calculate Outputs (Y) - Targets (Y') ↳ Second we multiply each element by 2 [8] Update Weights ↳ Use loss gradients to start back propagation ↳ Update some weights (light red) ↳ The values of the new weights are for demonstration purpose only, not based on real calculation. 🔍 Inference [9] Deactivate Dropout ↳ We set both dropout matrices to identity matrices ↳ The effect is to keep all the features as is. [10] Feed Forward ↳ Take the forward pass to make predictions about unseen data.

Tom Yeh

36,026 views • 2 years ago