I would say that nursery rhyme and incantation return us to states of innocence, and by that I mean we are returned to mystery, wonder, and fear.  In these states, we are not  just attentive, we’re invested.   I think the human need for this state of consciousness is innate and intuitive, whether of ancient or modern times..... We witness rhyme, rhythm, and patterning in Nature all the time, so to strike these things from poetry seems to me odd practice indeed. 

--Wendy Videlock; from 'Interview at Colorado Poets Center'