rough draft on what happens in the brain when you have an insight

post by Emrik (Emrik North) · 2024-05-21T18:02:47.060Z · LW · GW · 2 comments

Epistemic status: It is better to be wrong than to have no model at all. I recommend the footnotes.[1]


On my current models of theoretical[2] insight-making, it looks something like this:

  1. A gradual build-up and propagation of salience wrt some tiny discrepancy between highly confident specific beliefs
    1. This maybe corresponds to simultaneously-salient neural ensembles whose oscillations are inharmonic[3]
    2. Or in the frame of predictive processing: unresolved prediction-error between successive layers
  2. Immediately followed by a resolution of that discrepancy if the insight is successfwl
    1. This maybe corresponds to the brain having found a combination of salient ensembles—including the originally inharmonic ensembles—whose oscillations are adequately harmonic
    2. Super-speculative but: If the "question phase" in step 1 was salient enough, and the compression in step 2 great enough, this causes an insight-frisson[4] and a wave of pleasant sensations across your scalp, spine, and associated sensory areas

This maps to a fragile/chaotic high-energy "question phase" during which the violation of expectation is maximized (in order to adequately propagate the implications of the original discrepancy), followed by a compressive low-energy "solution phase" where correctness of expectation is maximized again.

In order to make this work, there are several homeostatic mechanisms which make the brain-state hug the border between phase-transitions as tightly as possible.[5] A corollary of this is that the brain maximizes dynamic correlation length between neurons,[6] which is when they have the greatest ability to influence each other across long distances (aka "communicate"). This is called the "critical brain hypothesis", and it suggests that good thinking is necessarily chaotic in some sense.

Another point is that insight-making is anti-inductive [LW · GW].[7] Theoretical reasoning is a frontier that's continuously being exploited based on the brain's native Value-of-Information-estimator, which means that the branches with the highest naively-calculated-VoI are also less likely to have any low-hanging fruit left. What this implies is that novel insights are likely to be very narrow targets—which means they could be really hard to hold on to for the brief moment between initial hunch and build-up of salience. Concisely: epistemic frontiers are anti-inductive.

  1. ^


  2. ^

    I scope my arguments only to "theoretical processing" (i.e. purely introspective stuff like math), and I don't think they apply to "empirical processing".

  3. ^

    Harmonic (red) vs inharmonic (blue) waveforms. When a waveform is harmonic, efferent neural ensembles can quickly entrain to it and stay in sync with minimal metabolic cost. Alternatively, in the context of predictive processing, we can say that "top-down predictions" quickly "learn to predict" bottom-up stimuli.

    Comparing harmonic (top) and inharmonic (bottom) waveforms.
  4. ^

    I basically think musical pleasure (and aesthetic pleasure more generally) maps to 1) the build-up of expectations, 2) the violation of those expectations, and 3) the resolution of those violated expectations. Good art has to constantly balance between breaking and affirming automatic expectations. I think the aesthetic chills associates with insights are caused by the same structure as appogiaturas—the one-period delay of an expected tone at the end of a highly predictable sequence.

  5. ^
  6. ^

    I highly recommend this entire YT series!

  7. ^

    I think the term originates from Eliezer, but Q Home has more relevant discussion on it—also I'm just a big fan of their chaoticoptimal reasoning style in general. Can recommend! 🍵


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comment by David Gross (David_Gross) · 2024-05-21T18:51:44.829Z · LW(p) · GW(p)

I'd be curious to hear your thoughts about how insight-frisson might be induced by psychedelics/marijuana in terms of your model. Anecdotally, these drugs seem to promote both a lot of false-positive insight-frisson experiences (the feeling of having an insight is vividly there, but the insight itself seems to dissolve upon inspection) and genuinely insightful insight-frisson experiences (a conceptual discrepancy you didn't even realize you had suddenly comes to light, and a way of resolving it follows soon after, in a way that endures beyond the acute drug experience).

Replies from: Emrik North
comment by Emrik (Emrik North) · 2024-05-21T19:05:59.313Z · LW(p) · GW(p)

I don't really know what psychedelics do in the brain, so I don't have a good answer. I'd note that, if psychedelics increases your brain's sensitivity wrt amplifying discrepancies, then this seems like a promising way to counterbalance biases in the negative direction (e.g. being too humble to think anything novel), even if it increases your false-positives.

I think psychedelics probably don't work this way, but I'd like to try it anyway (if it were cheap) while thinking about specific topics I fear I might be tempted to fool myself about. I'd first spend some effort getting into the state where my brain wants to discover those discrepancies in the first place, and I'm extra-sceptical the drugs would work on their own without some mental preparation.