In Bill Bryson's book titled "Mother Tongue. The Story of the English Language", on page 132 it says that "we must use each other for two things and one another for more than two."
So, when I read the following sentence quoted from a nih.gov paper, I wondered whether the writers correctly use each other.
From the point of view of a learner, like I am, the sentence might be okay only if one assumes that the writers want to mean that students interact each other in pairs (only two students at time) even if they are more than two; but, honestly, I doubt that the writers want to mean that.
Collaborative, case-based learning: how do students actually learn from each other?
Can anybody explain?