In my psychology class last year, we learned about an experiment that examined individualistic vs. collectivistic cultures, and I think it works as an apt analogy for how Davies and Moffat approach companions.
This experiment compared American and Japanese students. It asked them to describe themselves, first objectively and then how they saw themselves around different people. The Japanese students were puzzled by the first task, while Americans had a harder time with the second, the implication being that those from societies that prize individuality see themselves separate from the people around them, while those from cultures that value working together and harmony will view themselves in relation to the people around them. To reiterate: this is exactly what is happening in Moffat and Davies Who.