Search for: All records

People are remarkably capable of generating their own goals, beginning with child’s play and continuing into adulthood. Despite considerable empirical and computational work on goals and goal-oriented behaviour, models are still far from capturing the richness of everyday human goals. Here we bridge this gap by collecting a dataset of human-generated playful goals (in the form of scorable, single-player games), modelling them as reward-producing programs and generating novel human-like goals through program synthesis. Reward-producing programs capture the rich semantics of goals through symbolic operations that compose, add temporal constraints and allow program execution on behavioural traces to evaluate progress. To build a generative model of goals, we learn a fitness function over the infinite set of possible goal programs and sample novel goals with a quality-diversity algorithm. Human evaluators found that model-generated goals, when sampled from partitions of program space occupied by human examples, were indistinguishable from human-created games. We also discovered that our model’s internal fitness scores predict games that are evaluated as more fun to play and more human-like. 

Artificial Life has a long tradition of studying the interaction between learning and evolution. And, thanks to the increase in the use of individual learning techniques in Artificial Intelligence, there has been a recent revival of work combining individual and evolutionary learning. Despite the breadth of work in this area, the exact trade-offs between these two forms of learning remain unclear. In this work, we systematically examine the effect of task difficulty, the individual learning approach, and the form of inheritance on the performance of the population across different combinations of learning and evolution. We analyze in depth the conditions in which hybrid strategies that combine lifetime and evolutionary learning outperform either lifetime or evolutionary learning in isolation. We also discuss the importance of these results in both a biological and algorithmic context.