Loops, Hierarchies and Active Perception

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Ehud Ahissar runs the Ahissar Lab at the Weizmann Institute in Israel, where he studies the neuronal and behavioral mechanisms of perception. Ehud sees perception as a closed-loop process, in which organisms actively generate the sensory signals they interpret. Today, we discuss his development of an idea about how this kind of processing can account for our conscious experience. It's a type of dualism Ehud calls "perceptual dualism," different than the dualisms you may already know. I'll use his own words to summarize it here…

"The idea is that humans inevitably experience the world through two fundamentally different modes: digital brain–brain (BB) communication and analog brain–world (BW) interaction. In this view, the mind, and consciousness, emerge as social-like phenomena (in the philosophical sense), grounded in BB communication while constrained by BW interaction."

Take note of the term brain-brain, shortened as BB, and the term brain-world, shortened as BW, because throughout our discussion you'll often hear just BB and BW to refer to those two distinct domains.

So we discuss the ins and outs of his ideas, how came to them via studying active sensing in rodent whisker neurophysiology, how the brain implements this dualism via nested loops of neural circuitry that oppose and interlace with each other at multiple levels, and the idea that attractors, in the dynamical systems sense of attractor, may be the corresponding brain signatures of the digital phenomena that belong to the brain-brain mode of cognition.

• Ahissar Lab
• @ehudahissar; @ehudahissar.bsky.social
• Related papers
  • Digital–Analog Perceptual Duality
  • Closed-loop perception: gaps between artificial intelligence and biology

Read the transcript.

0:00 - Intro 5:09 - A new kind of dualism 7:19 - Ehud's whiskers background 14:10 - Digital-analog perceptual dualism 26:08 - Digital communication between humans 32:26 - Attractors as the digital-analog interface 39:50 - Consciousness 50:11 - Dynamics and perceptual bottleneck 51:47 - Language, AI, and digital symbols 1:00:54 - Computation and brains (digital and analog) 1:06:43 - Improving AI with event based activation 1:11:10 - Dualism 1:17:26 - The hard problem of consciousness 1:21:26 - BB and BW interaction 1:24:55 - Tension between BB and BW 1:34:28 - Looking forward 1:37:37 - Srange loops