Musical emotions have become a facet in music perception that is ubiquitously understood, yet difficult to define. Music holds the unique ability to communicate many emotions as well as change one's emotional state. For example, major and minor modes hold a special connection in music that drives emotional meaning. Research shows that many listeners hear major and minor music as sounding ``happy'' and ``sad,'' respectively; however, other research shows that many listeners (70\%) cannot discriminate between the major and minor musical modes \citep{Chubb2013c, Dean2017}. Thus, this dissertation uses behavioral and functional magnetic resonance imaging (fMRI) experiments to investigate the difference between those low-performing listeners who cannot and those high-performing listeners who can discriminate between major and minor musical stimuli. Studies that have demonstrated this divide in performance have used stimuli called tone-scrambles: rapid, random sequences of tones drawn from either a major or minor chord. Chapter 1 questions whether low-performing listeners would be able to discriminate between major and minor tone-scrambles if their tones are presented more slowly and with longer duration. Results from this chapter show that the performance of low-performing listenersdoes not improve when the stimuli are slowed down. In fact, performance was poorest in the slowest experimental condition. This implies that high-performing listeners do not differ from low-performing listeners solely in being able to extract differences in mode from very rapid stimuli. Chapter 2 investigates whether a 2-hour training regimen in the tone-scramble task is sufficient to improve performance of low-performing listeners. The results show that a small proportion of initially low-performing listeners benefit substantially from training. Most low-performers, however, show no significant improvement. This result shows that the gap that separates low- from high-performing listeners is not easily overcome. Finally, chapter 3 explores whether there are neural differences between the high- and low-performing listeners using fMRI. Results from the chapters of this dissertation suggest that certain listeners possess sensitivity to the difference between major and minor music that others lack and that this difference has little to do with musical training.