Apollo Research (London).
My main research interests are mechanistic interpretability and inner alignment.
So I believe I had in mind "active means [is achieved deliberately through the agent's actions]".
I think your distinction makes sense. And if I ever end up updating this article I would consider incorporating it. However, I think the reason I didn't make this distinction at the time is because the difference is pretty subtle.
The mechanisms I labelled as "strictly active" are the kind of strategy that it would be extremely improbable to implement successfully without some sort of coherent internal representations to help orchestrate the actions required to do it. This is true even if they've been selected for passively.
So I'd argue that they all need to be implemented actively (if they're to have a reasonable probability of success) but may be selected for passively or actively. I'm curious if you agree with this? If not, then I may have missed your argument.
(
For the convenience of other readers of this thread, the kind of strategies I labelled as strictly active are:
)
Extremely glad to see this! The Guez et al. model has long struck me as one of the best instances of a mesaoptimizer and it was a real shame that it was closed source. Looking forward to the interp findings!
Both of these seem like interesting directions (I had parameters in mind, but params and activations are too closely linked to ignore one or the other). And I don't have a super clear idea but something like representational similarity analysis between SwitchSAEs and regular SAEs could be interesting. This is just one possibility of many though. I haven't thought about it for long enough to be able to list many more, but it feels like a direction with low hanging fruit for sure. For papers, here's a good place to start for RSA: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3730178/
Great work! Very excited to see work in this direction (In fact, I didn't know you were working on this, so I'd expressed enthusiasm for MoE SAEs in our recent list of project ideas published just a few days ago!)
Comments:
Following Fedus et al., we route to a single expert SAE. It is possible that selecting several experts will improve performance. The computational cost will scale with the number of experts chosen.
Thanks! Fixed now
I've no great resources in mind for this. Off the top of my head, a few examples of ideas that are common in comp neuro that might have bought mech interp some time if more people in mech interp were familiar with them when they were needed:
- Polysemanticity/distributed representations/mixed selectivity
- Sparse coding
- Representational geometry
I am not sure about what future mech interp needs will be, so it's hard to predict which ideas or methods that are common in neuro will be useful (topological data analysis? Dynamical systems?). But it just seems pretty likely that a field that tackles such a similar problem will continue to be a useful source of intuitions and methods. I'd love if someone were to write a review or post on the interplay between the parallel fields of comp neuro and mech interp. It might help flag places where there ought to be more interplay.
I'll add a strong plus one to this and a note for emphasis:
Representational geometry is already a long-standing theme in computational neuroscience (e.g. Kriegeskorte et al., 2013)
Overall I think mech interp practitioners would do well to pay more attention to ideas and methods in computational neuroscience. I think mech interp as a field has a habit of overlooking some hard-won lessons learned by that community.
I'm pretty sure that there's at least one other MATS group (unrelated to us) currently working on this, although I'm not certain about any of the details. Hopefully they release their research soon!
There's recent work published on this here by Chris Mathwin, Dennis Akar, and me. The gated attention block is a kind of transcoder adapted for attention blocks.
Nice work by the way! I think this is a promising direction.
Note also the similar, but substantially different, use of the term transcoder here, whose problems were pointed out to me by Lucius. Addressing those problems helped to motivate our interest in the kind of transcoders that you've trained in your work!
Trying to summarize my current understanding of what you're saying:
Yes all four sound right to me.
To avoid any confusion, I'd just add an emphasis that the descriptions are mathematical, as opposed semantic.
I'd guess you have intuitions that the "short description length" framing is philosophically the right one, and I probably don't quite share those and feel more confused how to best think about "short descriptions" if we don't just allow arbitrary Turing machines (basically because deciding what allowable "parts" or mathematical objects are seems to be doing a lot of work). Not sure how feasible converging on this is in this format (though I'm happy to keep trying a bit more in case you're excited to explain).
I too am keen to converge on a format in terms of Turing machines or Kolmogorov complexity or something else more formal. But I don't feel very well placed to do that, unfortunately, since thinking in those terms isn't very natural to me yet.
At Apollo we're currently working on something that we think will achieve this. Hopefully will have an idea and a few early results (toy models only) to share soon.