Research has indicated that baseline pupil size may reflect attentional control capabilities. Several studies have demonstrated links between resting pupil measurements and various cognitive functions, including working memory capacity and fluid intelligence. The existing literature presents mixed evidence, with some studies supporting this relationship while others fail to replicate these findings. Moreover, the validity of this relationship across different populations has come into question, particularly when considering age-related physiological changes that affect pupil size. Our study sought to investigate whether the relationship between baseline pupil size and attentional control remains consistent across age groups. Results showed no meaningful correlation between baseline pupil size and attentional control. In examining possible explanations for these disparate results, we identified several methodological challenges, including inconsistencies in testing environments and variations in pupil measurement protocols, that may account for the conflicting findings in previous research. These observations highlight the importance of developing more standardized experimental approaches to properly evaluate baseline pupil size as an indicator of attentional control, particularly when studying aging populations.