Value learning is a proposed method for incorporating human values in an AGI. It involves the creation of an artificial learner whose actions consider many possible set of values and preferences, weighed by their likelihood. Value learning could prevent an AGI of having goals detrimental to human values, hence helping in the creation of Friendly AI.
Although there are many ways to incorporate human values in an AGI (e.g.: Coherent Extrapolated Volition, Coherent Aggregated Volition and Coherent Blended Volition), this method is directly mentioned and developed in Daniel Dewey’s paper ‘Learning What to Value’. Like most authors, he assumes that human’s goals would not naturally occur in an artificial agent and should be enforced in it. First, Dewey argues against the use of a simple use of reinforcement learning to solve this problem, on the basis that this lead to the maximization of specific rewards that can diverge from value maximization. For example, even if we forcefully engineer the agent to maximize those rewards that also maximize human values, the agent could alter its environment to more easily produce those same rewards without the trouble of also maximizing human values (i.e.: if the reward was human happiness it could alter the human mind so it became happy with anything).
To solve all these problems, Dewey proposes a utility function maximizer, who considers all possible utility functions weighted by their probabilities: "[W]e propose uncertainty over utility functions. Instead of providing an agent one utility function up front, we provide an agent with a pool of possible utility functions and a probability distribution P such that each utility function can be assigned probability P(Ujyxm) given a particular interaction history [yxm]. An agent can then calculate an expected value over possible utility functions given a particular interaction history" He concludes saying that although it solves many of the mentioned problems, this method still leaves many open questions. However it should provide a direction for future work.
Nick Bostrom also discusses value learning at length in his book Superintelligence. Value learning is closely related to various proposals for AI-assisted Alignment research. Since human values are complex and fragile, learning human values well is a challenging problem, much like AI-assisted Alignment (but in a less supervised setting, so actually harder). So this is only a practicable alignment technique for AGI capable of successfully performing a STEM research program in Anthropology. Thus value learning is (unusually) an alignment technique that improves as capabilities increase, and it requires around an AGI minimum threshold of capabilities to begin to be effective.
One potential challenge is that human values are somewhat mutable and AGI could affect them.