I want to add that my reply is as much motivated by Beth’s comment on children’s love and use of metaphor. Metaphor is pervasive at all ages. Broadly speaking it is what Cognitive Linguistics calls a “blending” process, whereby concepts in one domain are projected on to concepts in another. That we do this all the time with such ease and effectiveness in our language use is amazing, given the complexity of conceptualization involved. I would ask Beth if she has found any research on the ontogeny of metaphor.