This sort of analysis of shifting has been criticized by Ray Jackendoff, among others.See Jackendoff (1990) and Culicover and Jackendoff (2005) in this regard. Jackendoff and Culicover argue for an analysis like that shown with the flatter trees above, whereby heavy NP shift does not result from movement, but rather from a degree of optionality in the ordering of a verb's complements. The preferred order in English is for the direct object to follow the indirect object in a double-object construction, and for adjuncts to follow objects of all kinds; but if the direct object is "heavy", the opposite order may be preferred (since this leads to a more right-branching tree structure which is easier to process).
