it does, the relationship statue change twice while i was trying to see if it was really working, and i even got back later wondering if it was only when the dog first came on the camp, and its not the case. if you speak to him more than once, he start giving you his charming effect, maybe due to the fur that got stick on the character cloth? hmpf?
I did take note of the fact that Gael, Shadow, Wyll, appreciate when Scratch is petted, didn't catch that the approval wasn't only decorative but actual. Gonna test that with my new toon (I just hope to don't have to have good luck with the dice rolls).