RL with an evolved reward function. First described in [[Ackley and Littman, 1991 - Interactions between learning and evolution]]. Used as the basis for [[Ashley 2019 - Learning to Select Mates]] — What can be learned by trial and error and learning what actions work in what circumstances? - Has there been any consideration of MARL for ERL? - speciation via niches of the objective function? - Evolve a population of agents that exist in a world - Agents have a genome that specifies their objective function - There has to be room for different strategies - first, try classic game theory examples, e.g. prisioner’s delimena - **How to build enviroments that have niches?** -