The similarity-attraction effect, particularly in relation to personality, has emerged as a promising strategy for enhancing human-robot interaction (HRI). This research builds on existing robotics literature, which predominantly focuses on the extroversion trait and presents inconclusive findings regarding the similarity-attraction and complementary-attraction effects. Differing from prior work, this study implements a robotic personality using a cognitive architecture across three dimensions: Conscientiousness, Extroversion, and Agreeableness. We investigate the similarity-attraction effect through an experimental setup in which participants engage in free-form conversations with the robot.