Quantified NPs in certain positions are more likely to be assigned wide scope than are other QPs. For most of this discussion, we don't need to be more specific than this vague description of structural constraints. A comprehender's preferences for one scope interpretation is strong when multiple constraints converge to promote wide scope on a particular phrase, but when several constraints conflict, speakers are less likely to have a clear preference in scope interpretation. This effect of multiple constraints on the degree of ambiguity is known to be a general property of ambiguity resolution processes and is not about scope in particular. Next we consider three variations in scope judgments in English which can be attributed to these processing constraints.
Someone loves everyone.
Everyone loves someone. John assigned one student every problem. John praised one student every day. The correctness of linear order aside, I do want to embrace the processing nature of the argument. Every man loves a woman.