[smu3l]

"Some thought the game was harder with AI, others found it easier – but no one found it equally challenging."

So maybe it's just random? As in maybe some players randomly got an easier level in their first play than the second, and vice versa. I've played Don't Starve a little and each new game is very different.

Other points the article makes are more interesting, for example about players rating the AI version as more. It would be nice to see some confidence intervals, but I couldn't find the original research.

[Manishearth]

Agreed. Nothing in the article indicates that the results were due to a placebo effect and not due to randomness.

[746F7475]

Yep, they would need a lot more play time.

Like first two weeks of play in the "non-AI" version and then tell the player "AI" was added and ask after another two weeks if they find the new version more enjoyable in general