The following two paragraphs explain our emotional response to music and is worth reading even if you’re vaguely interested. None of this is particularly new to me, however it’s an excellent explanation, the best I’ve read, and doesn’t require any prior understanding of music theory. The square brackets are my additions.
The “fundamental musical problems” we will address in the study of counterpoint center around the way in which some basic principles of auditory perception and cognition (how the brain perceives and conceptualizes sound) play out in Western musical structure. For example, our brains tend to assume that sounds similar in pitch or timbre come from the same source. Our brains also listen for patterns, and when a new sound continues or completes a previously heard pattern, it assumes that the new sound belongs together with those others. On the other hand, the breaking of these regularities in the sonic environment can signal danger, or at the very least the need for heightened attention to be applied to the sonic “culprit.” Identifying irregularities in the sonic environment and boosting attention and adrenaline when one is found have been absolutely essential to the survival of the human species. These abilities are also what allows music to have the emotional effect that it does on so many people. Whether or not a composer or songwriter is aware of the science and psychology of hearing, a masterful composer mediates and plays with these basic concepts.
“Mediates” and “plays” are important ideas here. Music that simply makes it easy for the brain to parse and process sound is boring [A nursery rhyme] —it calls for no heightened attention, it doesn’t increase our heart rate, make the hair on the back of our neck stand up, or give us a little jolt of dopamine. On the other hand, music that constantly activates our innate sense of danger is hardly pleasant for most listeners [Free Jazz]. Thus, fundamental to most of the music we will study is the dance between tension and relaxation, motion and rest.