Thesis advisor: Sean MacEvoy / Humans can pay attention both to particular locations in space (“space-based attention”) and to specific objects (“object-based attention”). The goal of this study was to understand the role of object familiarity and complexity in the control of object-based attention. We used a well-known manifestation of object-based attention known as same-object advantage (SOA) to test this. In SOA, participants are faster at detecting a target event that takes place in a cued object than one that takes place in an uncued object, even when the distance between cue and target is kept fixed. To control shape familiarity, objects in the current study were randomly-generated irregular polygons known as Attneave shapes. Experiment 1 showed that SOA exists for these irregular shapes, even when participants are unfamiliar with them. In Experiment 2, participants first underwent training designed to familiarize them with a subset of the Attneave shapes used in Experiment 1. Again there was a significant SOA. If object-based attention is dependent upon object familiarity, we hypothesized that SOA, measured in terms of reaction time, should be greater in Experiment 2 than Experiment 1. Although there was a numerical increase in the reaction time signature of SOA in Experiment 2, this effect was not significant. While this does not strictly support our hypothesis, several aspects of this study suggest that object familiarity does play some role in mediating object-based attention. / Thesis (BS) — Boston College, 2013. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Psychology Honors Program. / Discipline: Psychology.