This paper investigates children's interpretation of scopally ambiguous sentences containing negation and quantification, such as "Donald didn't find two guys," and "Two horses didn't jump over the fence." It has been argued, in previous literature, that children interpret such sentences only on their surface scope reading, a phenomenon often called the Observation of Isomorphism. The present study shows, however, that this argument, even in its weakest interpretation, does not hold true, and that the apparent Isomorphism effect is an artifact of the experimental procedures used in previous studies. It also shows, based on the findings of a series of experiments with 5-year-olds, that the reason why children seemed, in previous studies, to favor surface scope interpretations was because they made their decisions based on the set or information that they viewed as most "relevant" in a given context. Children, on this view, do not differ from adults in syntax; the difference lies only in that they rank "salience" higher as a cue for general "relevance" than the Maxim of Charity, though adults view the Maxim of Charity as at least equally relevant.

This paper was previously published in Proceedings of the 2008 Annual Conference of the Canadian Linguistic Association (CLA 2008), ed. Susie Jones.