Last month two neuroscientists named Oliver Bones and Christopher Plack, of Manchester University and the Chinese University of Hong Kong, respectively, released a study that might explain why your parents don't like your music. And as you might have guessed, the answer is in their age.
The research paper, titled Losing the Music: Aging Affects the Perception and Subcortical Neural Representation of Musical Harmony, explores the effect that aging has on hearing. The two researchers found that the brain's ability to distinguish between certain sounds diminishes as people get older, which may explain why the elderly tend to engage less with music.
The study hinged on the difference between consonant and dissonant chords. These terms describe two opposites. When a chord is consonant, it includes two or more tones that are matched. The sound is sweet and comfortable. But when a chord is dissonant it sounds grating and messy. This is why consonance literally means sounding together whereas dissonance means sounding apart. It's a generalization, of course, but a lot of experimental music will tend to use dissonant chords, whereas more traditional pop relies more on consonance. Compare Aphex Twin to Mumford & Sons, for example.
Keeping this definition in mind, the study looked at two groups of participants: one under the age of 40 and the other over. It then required each group to rate the pleasantness of various pairs of notes played in a scale. During the experiment the participants' neural responses were recorded for their "frequency-following response," which measured how the participant's neurons responded to different pairs of sounds.
"Throughout the experiment the older participants found the consonant chords to be less pleasant than the younger participants," head researcher Christopher Plack told VICE. "But the older group also found the dissonant sounds to be more pleasant ." This was surprising, as dissonant chords are unquestionably less harmonious for a range of mathematical reasons that we won't get into. So if consonance seems less harmonious, and dissonance seems less jarring, the diversity of music exists in a more bland middle range for older people. As Plack summarized, "I t was as if their perception of the difference between consonance and dissonance was massively reduced."
This research also consistently showed that as we age so does our temporal coding. That controls the timing of the firing of groups of brain cells, directly impacting our ability to distinguish consonant sounds from dissonant ones. "As we age, nerve cells in the brain become less able to represent rapid fluctuations in sounds," Plack explained. "This may be why we become more entrenched in our particular music and less responsive to new ideas, or even in music generally."
According to the study's co-researcher, Oliver Bones, losing the ability to hear the difference in chords seriously affects musical appreciation. "We couldn't enjoy music without dissonance, because if you don't have a sense of dissonance you can't enjoy consonance," he said. "This distinction is central to Western music and it determines musical 'key.'" The range of emotions evoked by music are a product of intuitively understanding key, he added.
And while our temporal coding can diminish with age, all hope is not lost. "If you listen to a lot of music and think musically you can actually strengthen your neural responses to music," Plack said. "So the more you listen to music, the more responsive your neurons become."
Follow Tim on Twitter.