Alter self / Shapechange: Doppelganger unconscious

[Talasek]

Running Age of Worms, Harsh Reflection with Pathfinder Rules right now.

We were wondering if an unconscious Doppelganger would morph back to natural form as he can't concentrae on his form.
To help the players i ruled yes, but iam not sure if its ok.

[Remco Sommeling]

I don't think a doppelganger needs to concentrate to maintain shape, so basically I don't think so, though I think it is fitting anyway.