Aspect semantically denotes two concepts: eventualities and their endpoints, or the speaker’s perspective of an event. These aspectual distinctions respectively refer to telicity and perfectively. Telicity specifically denotes the internal temporal organization of events in regards to their endpoint (telic) or lack thereof (atelic). The telic/atelic distinction has been studied in semantics using logical analysis, in particular mereological relations (the relation of parts to parts and parts within wholes) and scalar theory (a representation of measurement composed of degrees that are partially or totally ordered). This thesis presents a psycholinguistic experiment investigating the cognitive nature of one component of aspectual realization, namely telicity, in English. In accordance with the predictions made by mereological and scalar theories for the semantic composition of telicity, it is hypothesized that telic constructions are semantically more complex than atelic constructions. This complexity specifically refers to maximalization; a process which Filip (2008) predicts takes place exclusively in the derivation of telic events. This prediction is made under the assumption that a correlation exists between the number of derivational steps and cognitive complexity. Specifically, constructions which involve a greater number of steps in their derivation are hypothesized to also involve a greater amount of cognitive resources in order to be successfully computed. This correlation is supported by recent research investigating the role of working memory in sentence comprehension. Recent studies have found constructions with greater syntactic derivational complexity are susceptible to interference and processing trade-offs when processed under heavy memory loads. Based on this, if telic constructions involve a greater derivational complexity compared to atelic counterparts, they therefore can be hypothesized to be more susceptible to interference and processing trade-offs from increased memory loads. The results of the experiment provide evidence supporting this prediction, ultimately suggesting telicity is a grammatically more complex process than atelicity. / Thesis / Master of Science (MSc)