The present study aims to investigate the effect of different types of background music on behavioral and physiological measures in a variety of cognitive tasks. A total of 40 participants were asked to complete four cognitive tasks (immediate recall, delayed recall, phonemic fluency, trail-making) in a 2x2 (fast/slow tempo x positive/negative valence) within-subjects design. Throughout the study, participants wore a mobile eye tracker to record pupillary activity in addition to behavioral measures. Behavioral data show that participants performed worse on the immediate recall task when listening to slow and negative background music while they performed better on phonemic fluency when listening to fast and positive music, compared to the other type of music, respectively. Eye-tracking data including pupil dilation will be analyzed to find indicators of cognitive activity corresponding to the behavioral results. The collected behavioral data were analyzed using ANOVAs and mixed-effect models, while pupillary activity was pre-processed and then calculated using IPA and LHIPA (Duchowski et al., 2020) metrics. We will present and discuss both these measures, their correlations, and their implications with a focus on the eye-tracking data.