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nullc • today at 12:51 AM • 2 replies • view on HN

> It could be encoding anything in its adjective choices etc.

There is a common understanding with respect transformers the the output text is the only channel between one invocation and the next. ... so if it wanted to be thinking some 'hidden thoughts' it would have to be modulating its word-choice.

I think this is an artifact of tutorials on attention showing the system proceeding and looking back at words. But the information in the KV cache is not words-- it's entirely latent data, and in the interior layers they KV caches don't even tend to have that much to do with words. Their only guaranteed relationship with the input words is that they're a deterministic function of all the input tokens up to that point.

This means that a autogressive transformer could be having a whole complicated invisible discussion going on in the KV entries which was arbitrarily unrelated to what it was saying. And if it wasn't so it would be much more difficult do stuff like exactly copy a list but then truncate at the Nth entry as the simplest way to do that is to count down internally.

This is not, in my view, a concern or issue-- the model saying stuff that is inconsistent with it's "thinking" is a very high entropy configuration that would not be selected for in training unless you were more or less trying to do that. So not even 'could be' --but always is as an integral part of working.

And the useful safety relevant advice is don't undertake training that trains the model to be two-faced and it simply won't be... because being two-faced is a much more complicated state. You can even see it in humans w/ brainwashing: force someone to say something enough and they'll usually believe it, not just say it even though you were only supervising what they said.

Ironically and unfortunately the only credible kind of training I can think of that might produce duplicitous behavior is RL with "safety filters"--- if you have some dumb nanny process watching what the model says but then reward it for achieving a task, you're doing exactly the kind of training that can produce that mismatch. "To solve this task I need to hack this process but if I do so obviously I'll get punished..."

The greater concern with latent reasoning would be that potentially you'd be operating in a regime where the total computational depth is many times the model*kvcache size hold, potentially in a regime that was never trained at all. It could be arbitrarily far out of distribution. It might even say a naughty word or tell a racist joke!


Replies

chrisweekly • today at 1:58 AM

Thank you for this gem of a comment.

I'm no expert (let alone compared to others weighing in here on HN), but this strikes me as incisive -- and it clearly articulates a logical case (beyond my previously merely instinctual aversion) against such "safety filters" / "nanny" processes. It also resonates with ancient (e.g. Buddhist) ideas about the futility of trying to exert control, such efforts most often being counter-productive.

octoberfranklin • today at 1:46 AM

But the information in the KV cache is not words-- it's entirely latent data,and in the interior layers they KV caches don't even tend to have that much to do with words

The context gets added back to the latent vectors (which are the Q,K inputs) after every transformer layer, so they are "at least 50% words".

Also, in an N-layer transformer, there is a strong bound of N layers of uninterpretable deviation from something that is a literal token. Now sure, in a transformer with hundreds of layers that isn't saying much.

If you start doing continuous chain of thought in a 1M-token context you're hundreds of millions of layers away from tokens.

I think the people who worry about interpretability (I don't) consider that a big jump.