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Adam Marblestone — AI is missing something fundamental about the brain

Dwarkesh Podcast

Hosted by Dwarkesh Patel

1h 49m
Transcript

Original podcast

Summary

Written by a model from the transcript; not yet reviewed.

This episode features a discussion on the fundamental differences between how artificial intelligence and the human brain process information, exploring the limits of current large language models. The guest and host examine the hypotheses that biological intelligence relies on complex, evolutionarily encoded loss functions, omnidirectional inference, and a distinct separation between a learning subsystem like the cortex and a steering subsystem responsible for innate drives and reward signals. They also discuss the scaling of neural architectures, the role of cellular complexity, and how focused research organizations might map mouse and human brains.

  • The human brain likely uses complex, evolutionarily encoded loss functions and a separate steering subsystem rather than simple next-token prediction. 2:39
  • Mapping the brain through molecularly annotated connectomes will help bridge the gap between biological intelligence and artificial neural networks. 18:00
  • Formalized math verification languages like Lean create verifiable signals that improve automated theorem proving. 1:24:01

Chapters

  1. 0:00
    The Big Question of Brain vs. LLMs

    Dwarkesh opens the episode by posing the fundamental question of why LLMs lag behind human cognition despite massive data.

  2. 0:56
    Neural Net Architecture and Loss Functions

    The discussion shifts to the key components of neural nets—architecture, hyperparameters, learning algorithms, and the often overlooked role of loss functions.

  3. 2:20
    Learning vs. Steering: Two Brain Subsystems

    Dwarkesh and the host dissect the division between the learning subsystem (plasticity) and the steering subsystem (innate wiring).

  4. 3:32
    Brain’s Omnidirectional Prediction Engine

    Exploration of the hypothesis that cortical areas act as a universal prediction engine, capable of inferring any subset of variables from any other subset.

  5. 6:27
    Steering Subsystem and Innate Reward Signals

    The conversation turns to the brain’s steering subsystem, innate reward functions, and how evolution encodes complex loss functions into neural circuitry.

  6. 9:26
    Cell Types and Genetic Wiring

    The conversation moves to the diversity of cell types in the steering subsystem and how genetic wiring specifies specialized circuits.

  7. 14:00
    Omnidirectional Inference and Language

    Exploration of whether language and other complex functions required new cortical wiring or simply leveraged existing inference capabilities.

  8. 18:00
    Future Directions: Mapping the Mouse Brain

    The episode concludes with a call to map the mouse brain comprehensively to ground neuroscience in empirical data.

  9. 36:28
    Scaling Neural Architectures in Evolution

    Discussion of how small genetic changes could lead to large increases in cortical size and learning capacity across species.

  10. 42:44
    RL, Value Functions, and the Brain

    The host asks about reinforcement learning in the brain, contrasting model-free RL in basal ganglia with model-based cortical inference.

  11. 47:12
    Neural Network Value Heads and Amortized Inference

    Discussion of value heads in neural networks and how they predict rewards, linking to amortized rollouts and statistical predictions.

  12. 47:54
    Model-Free Reinforcement Learning at a Civilizational Scale

    Exploration of how human societies learn through trial and error, comparing it to model-free RL and evolutionary processes.

  13. 48:52
    Cellular Complexity Beyond Synapses

    Debate over whether cellular-level processes add computational value beyond synaptic connections, and the role of molecular changes.

Highlights

  • 0:00

    The Brain Versus LLMsinsight

    The host opens by questioning why LLMs require vastly more data than humans while possessing only a fraction of human capabilities.

  • 1:32

    Complex Loss Functions in Evolutioninsight

    The guest argues that evolution has encoded complex loss functions and learning curricula into the brain rather than relying on mathematically simple loss functions.

  • 3:44

    Omnidirectional Prediction Engineinsight

    Unlike LLMs which predict the next token conditionally, the cortex may act as an omnidirectional prediction engine capable of inferring any subset of variables.

  • 9:16

    Steering Subsystem and Innate Rewardsinsight

    The discussion explores how innate reward functions and primitive responses in subcortical areas are modeled and predicted by the learning subsystem.

  • 30:50

    Bespoque Cell Typesdata

    Single-cell atlases reveal a high diversity of bespoke cell types in the steering subsystem compared to the repeating architecture of the cortex.

  • 44:47

    Model-Free Reinforcement Learninginsight

    The conversation examines how temporal difference learning and dopamine prediction error signals relate to primitive reinforcement learning in the basal ganglia.

  • 1:12:10

    Cost of Connectome Mappingdata

    The guest details how new optical microscopy techniques aim to reduce the cost of mapping a mammal connectome from billions down to tens of millions of dollars.

Quotes

  • “I think evolution may have built a lot of complexity into the loss functions.”
    Unnamed speaker · 1:57
  • “Actually, many different loss functions were different areas, turned on at different stages of development.”
    Unnamed speaker · 2:01
  • “So, so any one area of cortex is just trying to predict.”
    Unnamed speaker · 3:32
  • “I think a lot of the things I'm saying, by the way, are extremely similar to like what Yann LeCun would say.”
    Unnamed speaker · 4:43
  • “That's going to enact, activate in me innate embarrassment and shame, and I'm going to want to go hide and whatever.”
    Unnamed speaker · 7:12
  • “And so I'm going to do further learning based on that.”
    Unnamed speaker · 8:50
  • “It has to like run on 20 watts.”
    Dwarkesh Patel · 51:13
  • “Because it's, it was just, the only reward function it had was like make paperclips.”
    Unnamed speaker · 58:07
  • “The AIs we're making based on these ideas are working surprisingly well.”
    Unnamed speaker · 1:00:53
  • “It's like billion, low billions of dollars scale funding in a very concerted way, I would say.”
    Unnamed speaker · 1:11:38
  • Labelbox 49:57–50:42

About this episode

Adam Marblestone https://twitter.com/AdamMarblestone is CEO of Convergent Research https://www.convergentresearch.org/. He’s had a very interesting past life: he was a research scientist at Google Deepmind on their neuroscience team and has worked on everything from brain-computer interfaces to quantum computing to nanotech and even formal mathematics. In this episode, we discuss how the brain learns so much from so little, what the AI field can learn from neuroscience, and the answer to Ilya’s question: how does the genome encode abstract reward functions? Turns out, they’re all the same question. Watch on YouTube https://youtu.be/_9V_Hbe-N1A; read the transcript https://www.dwarkesh.com/p/adam-marblestone. Sponsors * Gemini 3 Pro https://gemini.google.com recently helped me run an experiment to test multi-agent scaling: basically, if you have a fixed budget of compute, what is the optimal way to split it up across agents? Gemini was my colleague throughout the process — honestly, I couldn’t have investigated this question without it. Try Gemini 3 Pro today gemini.google.com https://gemini.google.com * Labelbox https://labelbox.com/dwarkesh helps you train agents to do economically-valuable, real-world tasks. Labelbox’s network of subject-matter experts ensures you get hyper-realistic RL environments, and their custom tooling lets you generate the highest-quality training data possible from those environments. Learn more at labelbox.com/dwarkesh https://labelbox.com/dwarkesh To sponsor a future episode, visit dwarkesh.com/advertise https://www.dwarkesh.com/advertise. Timestamps (00:00:00) – The brain’s secret sauce is the reward functions, not the architecture (00:22:20) – Amortized inference and what the genome actually stores (00:42:42) – Model-based vs model-free RL in the brain (00:50:31) – Is biological hardware a limitation or an advantage? (01:03:59) – Why a map of the human brain is important (01:23:28) – What value will automating math have? (01:38:18) – Architecture of the brain Further reading Intro to Brain-Like-AGI Safety https://www.lesswrong.com/s/HzcM2dkCq7fwXBej8 - Steven Byrnes’s theory of the learning vs steering subsystem; referenced throughout the episode. A Brief History of Intelligence https://www.abriefhistoryofintelligence.com/book - Great book by Max Bennett on connections between neuroscience and AI Adam’s blog https://longitudinal.blog/, and Convergent Research’s blog on essential technologies https://www.essentialtechnology.blog/. A Tutorial on Energy-Based Learning http://yann.lecun.com/exdb/publis/pdf/lecun-06.pdf by Yann LeCun What Does It Mean to Understand a Neural Network? https://arxiv.org/abs/1907.06374 - Kording & Lillicrap E11 Bio https://www.e11.bio/ and their brain connectomics approach Sam Gershman on what dopamine is doing in the brain https://gershmanlab.com/pubs/GershmanUchida19.pdf Gwern’s proposal https://www.reddit.com/r/reinforcementlearning/comments/9pwy2f/wbe_and_drl_a_middle_way_of_imitation_learning/ on training models on the brain’s hidden states This is a public episode. If you would like to discuss this with other subscribers or get access to bonus episodes, visit www.dwarkesh.com https://www.dwarkesh.com?utm_medium=podcast&utm_campaign=CTA_1

Transcript

0:00
1:49:53

21,106 words · 2 speakers

Speaker names marked are inferred from speaking time and the show’s known hosts — they are not voice-verified.

Topics

  • cortex
  • backprop
  • Lean
  • Neural Network
  • Python
  • Human Brain
  • hippocampus
  • neural networks
  • energy‑based models
  • E11

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