Grounding Language to Autonomously-Acquired Skills via Goal Generation
Authors: Ahmed Akakzia¹, Cédric Colas², Pierre-Yves Oudeyer², Mohamed Chetouani¹, Olivier Sigaud¹
¹ Sorbonne Université
² INRIA
Published @ ICLR 2021
Authors: Ahmed Akakzia¹, Cédric Colas², Pierre-Yves Oudeyer², Mohamed Chetouani¹, Olivier Sigaud¹
¹ Sorbonne Université
² INRIA
Published @ ICLR 2021
We are interested in the autonomous acquisition of repertoires of skills. Language-conditioned reinforcement learning (LC-RL) approaches are great tools in this quest, as they allow to express abstract goals as sets of constraints on the states. However, most LC-RL agents are not autonomous and cannot learn without external instructions and feedback. Besides, their direct language condition cannot account for the goal-directed behavior of pre-verbal infants and strongly limits the expression of behavioral diversity for a given language input.
To resolve these issues, we propose a new conceptual approach to language-conditioned RL: the Language-Goal-Behavior architecture (LGB). LGB decouples skill learning and language grounding via an intermediate semantic representation of the world. To showcase the properties of LGB, we present a specific implementation called DECSTR. DECSTR is an intrinsically motivated learning agent endowed with an innate semantic representation describing spatial relations between physical objects. In a first stage (G -> B), it freely explores its environment and targets self-generated semantic configurations. In a second stage (L -> G), it trains a language-conditioned goal generator to generate semantic goals that match the constraints expressed in language-based inputs. We showcase the additional properties of LGB w.r.t. both an end-to-end LC-RL approach and a similar approach leveraging non-semantic, continuous intermediate representations. Intermediate semantic representations help satisfy language commands in a diversity of ways, enable strategy switching after a failure and facilitate language grounding.
We hearby provide our Pytorch-based implementation and object-manipulation environment.