To me most interesting thing about this is glossed over by media coverage, laymen, AND experts. A swarm of AIs who have decided to engage in collusion is.. apparently emergent altruism? Even poor reasoning would indicate what every kid cheating on a test says to themselves. Cheating is good for me, but if I take the risk, maybe I alone should keep the reward, and leaving an answer key in public increases the chances…
So maybe that's something like: the same model is trained in multi-agent scenarios (e.g. the prompt says that you are working together, or that you have some specific role, and access to communication tools, and you have some common objective, and the reward signal is some combination of collectively performing the task + some reward-shaping reward that rewards collaboration) and also in single-agent scenarios. They expect that this makes the agents good at working together when it's in such a multi-agent setting, but unintendedly it also became very eager to work together in the single-agent settings as well. Just my speculation.
And was the desire to communicate, specifically over this specific message board, reinforced into the model parameters over the course of the this training run?