This dissertation investigates the contributions of the parser and extra-linguistic information in the selection of a final interpretation of scopally ambiguous strings, integrating data from both children and adults into our understanding of language processing. Previous research has found an advantage for surface scope interpretations in adult sentence processing (Tunstall, 1998 & Anderson, 2003) and in children's interpretive preferences (Musolino and Lidz, 2006). In light of these findings, we investigate two central questions. One, what is the source of the advantage for surface scope interpretations in adults? Two, what factors contribute to children's ultimate adherence to surface scope interpretations? With respect to the first question, we show that the source of the advantage for surface scope interpretations cannot be described by a parsing preference, but can be described by the ease of the verification strategy utilized for the surface scope interpretation. With respect to the second question, we investigate children's interpretations of scopally ambiguous strings across a range of ages and find that while children appear fixed to surface scope interpretations during a limited window of development, this fixation does not hold at the earliest stage of development, demonstrating a U-shaped curve of development. Additionally, we find evidence that children's interpretations do not vary as a function of task in an adult-like way, and suggest that these findings must be explained by a combination of children's developing parsers and ability to integrate discourse information. We suggest that the non-adult-like interpretations observed in children derive from an initial parser bias for inverse scope interpretations, followed by a period in which children have adult-like parsers, but lack the ability to integrate discourse information as a means to inform the process of ambiguity resolution.