Randy and I discuss his LEABRA cognitive architecture that aims to simulate the human brain, plus his current theory about how a loop between cortical regions and the thalamus could implement predictive learning and thus solve how we learn with so few examples. We also discuss what Randy thinks is the next big thing neuroscience can contribute to AI (thanks to a guest question from Anna Schapiro), and much more.
- Computational Cognitive Neuroscience Laboratory.
- The papers we discuss or mention:
- His youTube series detailing the theory and workings of Leabra:
- The free textbook:
A few take-home points:
- Leabra has been a slow incremental project, inspired in part by Alan Newell’s suggested approach.
- Randy began by developing a learning algorithm that incorporated both kinds of biological learning (error-driven and associative).
- Leabra’s core is 3 brain areas – frontal cortex, parietal cortex, and hippocampus – and has grown from there.
- There’s a constant balance between biological realism and computational feasibility.
- It’s important that a cognitive architecture address multiple levels- micro-scale, macro-scale, mechanisms, functions, and so on.
- Deep predictive learning is a possible brain mechanism whereby predictions from higher layer cortex precede input from lower layer cortex in the thalamus, where an error is computed and used to drive learning.
- Randy believes our metacognitive ability to know what we do and don’t know is a key next function to build into AI.
0:00 – Intro
3:54 – Skip Intro
6:20 – Being in awe
18:57 – How current AI can inform neuro
21:56 – Anna Schapiro question – how current neuro can inform AI.
29:20 – Learned vs. innate cognition
33:43 – LEABRA
38:33 – Developing Leabra
40:30 – Macroscale
42:33 – Thalamus as microscale
43:22 – Thalamocortical circuitry
47:25 – Deep predictive learning
56:18 – Deep predictive learning vs. backrop
1:01:56 – 10 Hz learning cycle
1:04:58 – Better theory vs. more data
1:08:59 – Leabra vs. Spaun
1:13:59 – Biological realism
1:21:54 – Bottom-up inspiration
1:27:26 – Biggest mistake in Leabra
1:32:14 – AI consciousness
1:34:45 – How would Randy begin again?