This study contributes to the ongoing exploration of methods to enhance the environmental design, cognitive function, and overall wellbeing, primarily focusing on understanding the modulation of human cognitive performance by artificial lighting conditions. In this investigation, participants (N=35) engaged with two distinct architectural contexts, each featuring five different lighting conditions within a virtual environment during specific daytime scenarios. Responding to a series of cognitive memory tests, we measured participant test scores and the corresponding reaction time. The study's findings, particularly in Backward Digit Span Tasks (BDST) and Visual Memory Tasks (VMT), indicate that diverse lighting conditions significantly impacted cognitive performance at different times of the day. Notably, the BDST scores were mainly affected by lighting conditions in the afternoon session, whereas the VMT scores were primarily influenced in the morning sessions. This research offers support for architects and engineers as they develop lighting designs that are sensitive to the cognitive performance of occupants. It highlights the advantages of utilizing VR simulations in the AEC industry to assess the impact of lighting designs on users. Further research can lead to the development of lighting systems that can promote better cognitive function and overall wellbeing.