This post introduces the concept of _model splintering_, which seems to be an overarching problem underlying many other problems in AI safety. This is one way of more formally looking at the out-of-distribution problem in machine learning: instead of simply saying that we are out of distribution, we look at the model that the AI previously had, and see what model it transitions to in the new distribution, and analyze this transition.
Model splintering in particular refers to the phenomenon where a coarse-grained model is “splintered” into a more fine-grained model, with a one-to-many mapping between the environments that the coarse-grained model can distinguish between and the environments that the fine-grained model can distinguish between (this is what it means to be more fine-grained). For example, we may initially model all gases as ideal gases, defined by their pressure, volume and temperature. However, as we learn more, we may transition to the van der Waal’s equations, which apply differently to different types of gases, and so an environment like “1 liter of gas at standard temperature and pressure (STP)” now splinters into “1 liter of nitrogen at STP”, “1 liter of oxygen at STP”, etc.
Model splintering can also apply to reward functions: for example, in the past people might have had a reward function with a term for “honor”, but at this point the “honor” concept has splintered into several more specific ideas, and it is not clear how a reward for “honor” should generalize to these new concepts.
The hope is that by analyzing splintering and detecting when it happens, we can solve a whole host of problems. For example, we can use this as a way to detect if we are out of distribution. The full post lists several other examples.
Planned opinion:
I think that the problems of generalization and ambiguity out of distribution are extremely important and fundamental to AI alignment, so I’m glad to see work on them. It seems like model splintering could be a fruitful approach for those looking to take a more formal approach to these problems.
Planned summary for the Alignment Newsletter:
Planned opinion:
Cool, good summary.