This study investigates the relationship between baseline pupil size and performance in the Serial Reaction Time Task (SRTT), and its connection to explicit knowledge as measured by wagering performance. Implicit learning is a fundamental cognitive process, yet its underlying mechanisms remain debated. The unexpected event hypothesis (UEH) suggests that behavioural changes reflect cognitive surprise and learning. By analyzing reaction time improvements in the SRTT and wagering-based measures of explicit awareness, this research aims to clarify how baseline pupil size predicts task performance and explicit knowledge acquisition. Findings contribute to a deeper understanding of implicit learning processes and the role of physiological markers such as pupil size in cognitive adaptation.