There is a difference between something that is considered to be “well-known” or folk-knowledge and demonstrable evidence. The sentence quoted here is not untrue, or exaggerated, however, if the Editor wishes us to explore this further, we would kindly request the Reviewer provide us with examples of publications where this has been empirically demonstrated, as we have not found any in our own searches.
I felt the discussion about changes in greeting behaviour as an early indicator was interesting and could be expanded.