> I don’t know how you could do that when training on internals
an earlier version of our method actually tried only training affine layers between the residual streams instead of full finetuning—because the backdoor behavior is inherently non linear in ways that the original features don’t pick up, we get a very strong theoretical case for it having to spike. only problem: the benign noise was too big. the core assumption was that post-training mostly rotates activations, which our affine map could pick up on, but it seems there is a bunch of non linearity still involved if you start looking at deeper layers. but i think this is a good example for a direction that activation based approaches might try to leverage to ‘restrict learning’ to only certain types of changes from post-training.
> Surely these show up more in the internals if the model is deliberately trying to not explicitly show it’s bad behavior?
partially—to some extent we rely on this for then exploiting it (the near-trigger prompts already spiking), but for almost all prompts, there seems to be very little signal. since we are only aligning the residual stream, not the actual computations, you can imagine some layers checking ‘is this in the trigger region?’ and compiling their results in the residual stream. but for most prompts, none of these layers will activate and the model would just write nothing special to the residual stream. i think you might be anthropomorphizing too much—it’s not that the model goes ‘i wanna do this, i wanna do this—but i can’t right now’, but instead simply only ever starts ‘scheming’ once earlier layers decided it should.
> well fwiw this does seem pretty plausible for a scheming model to be thinking...
i was thinking more of a traditional backdoor and I think you are partially right but I think roughly the same argument applies. You can imagine there happening some additional computations that even enter the residual stream and probably will be found in the RS-aligned model. But it would basically seem like something of an irrelevant offset rather than actual scheming because it didn’t ever learn how to turn these activations into anything real—like even if the RS-activations originally encoded it’s plans to demolish all of humans, since in the end it always suppresses itself, suddenly the same encoding is just some weird offset that happens regardless of prompts but doesn’t ever do anything.
but i’m not 100% sure about this yet, maybe there are some weird ways in which the activations can still be leveraged as more than just an offset once they are there.