  While there has been significant progress in curriculum learning and
continuous learning for training agents to generalize across a wide variety of
environments in the context of single-agent reinforcement learning, it is
unclear if these algorithms would still be valid in a multi-agent setting. In a
competitive setting, a learning agent can be trained by making it compete with
a curriculum of increasingly skilled opponents. However, a general intelligent
agent should also be able to learn to act around other agents and cooperate
with them to achieve common goals. When cooperating with other agents, the
learning agent must (a) learn how to perform the task (or subtask), and (b)
increase the overall team reward. In this paper, we aim to answer the question
of what kind of cooperative teammate, and a curriculum of teammates should a
learning agent be trained with to achieve these two objectives. Our results on
the game Overcooked show that a pre-trained teammate who is less skilled is the
best teammate for overall team reward but the worst for the learning of the
agent. Moreover, somewhat surprisingly, a curriculum of teammates with
decreasing skill levels performs better than other types of curricula.
