Sensory gating is a mechanism that inhibits neurological responses to redundant information. Although studied within clinical populations, sensory gating has rarely been investigated with respect to aging. The present research investigated age-related changes in auditory sensory gating using electroencephalography and quantified the effect of age on adaptive gating responses for oddball stimuli. Age-related differences in sensory gating and oddball responses were observed in late-stage auditory processing, where older adults exhibited weaker sensory gating. An attenuated P200 for first and second clicks seen in the aging group may explain the weaker sensory gating ratio seen in older participants. Furthermore, replacing the second click with oddball stimuli attenuated, but did not eliminate sensory gating, indicating that sensory gating is a dynamic mechanism. Findings suggest that sensory gating is diminished for older adults and may transform from an adaptive mechanism under executive control to a pre-attentive limiter of auditory processing. This thesis is dedicated to those individuals with which this document would not have been possible. Firstly, I would like to thank and acknowledge my committee for their feedback and advisement. Secondly, to my supervisor, Chris Herdman, for creating a lab where the focus is not only on executing fantastic research, but on how research findings can make an everlasting impact on real-world issues. I am so grateful to have been a member of the Advanced Cognitive Engineering (ACE) Lab, and have continued my passion for applied cognitive neuropsychology with my current position at the National Research Council. I am also forever in debt to Kathy Van Benthem, whose patience and guidance made this thesis possible. Thank you, Kathy, for your many hours spent helping me to connect the dots, and for taking the time to integrate me into the world of aviation research. I would also like to thank the National Research Council, for playing a role in this research, and for continuing to put incredible value in the physiological assessment of behavior within the aviation industry. And a heartfelt thank you to Heather Wright-Beatty, for providing me the opportunity to continue to work towards the completion of my degree, despite starting a full-time job within the Human Factors group this past January. Thank you to my Mum, Deb Roy, and sisters, Santana Paleske and Scarlett Schumacher, who have always been incredibly supportive of my journey and stood by my side through every step, despite the distance and crazy ideas. And finally, to Jesse Lock, who has stood by my side through my best and worst times. As we close the door iv on both of our Masters degrees, I wish that we continue to enjoy the music of life, and may we always find time to appreciate the push + pull of the journey.