Humans have evolved all sorts of advantageous adaptations for survival and reproduction, the two aspects of living things that drive natural selection. Music, however, does not seem to directly benefit either. So why has it evolved as such a significant and indispensable part of human culture for over (at least) the last 35,000 years2? What links music to human survival, making it so ubiquitous across time?
Neuroscientists who study music’s effects on the brain are split into two factions—those that believe music did evolve as some kind of evolutionary adaptation (to explain exactly why, only theories exist), and those that believe it was merely an incident that was not shaped by, nor did it shape, the evolution of humans into what we are today. The former concludes that music increased human fitness through reproduction and survival. The latter says music didn’t affect our fitness at all.
Charles Darwin, the face of evolutionary biology himself, believed music evolved through courtship rituals, and thus was a reproductive adaptation used to increase reproductive success. He used bird courtship songs as evidence and claimed, in his Descent of Man, that music and sex are inexplicably linked2.
In his 1997 publication of How the Mind Works, Steve Pinker argued against Darwin and claimed that music was the side effect of other adaptations, and has no evolutionary significance. Echoing the thoughts of William James, a psychologist from the late 1800s, Pinker believes that rhythms and melodies are the by-products of other evolutionary adaptations such as walking, running, and language1. Rhythms reflect the beats with which we walk and the syllables with which we talk, but they did not evolve for any direct purpose, and did not increase fitness in any way.
A psychologist from Oxford University, Robin Dunbar, states that music evolved as social glue, like the practice of grooming, which held together bonds between people. Scientists have shown through a series of tests that endorphin levels are higher after people perform and/or listen to music2. Higher endorphin levels lead to increased social behavior.
But another neuroscientist disagrees with Dunbar’s hypothesis, and agrees with Pinker in saying that music did not evolve for any significant purpose. Aniruddh Patel, from the Neurosciences Institute in La Jolla, California, counters Dunbar’s argument by saying that those with social impairments should not be able to comprehend music or have musical abilities if music did evolve as an agency of social bonding. Yet many people with autism have the same perception and ability to play music as those without autism2.
The controversy surrounding this debate about whether or not music evolved as a specific adaptation or merely a side effect may never end. There is too much we don’t know, such as how music could possibly have increased our fitness, and how exactly music heightens endorphin levels. The most likely possibility, cited most often by scientists, is that music is not an adaptation but rather a side effect of socializing, since it evolved primarily as an activity prevalent within groups of people. Nonetheless, the positive effects of music are being realized further and further every day, from musical therapy to the effects of classical music on the brain while studying. For now, we can revel in the brilliant way music brings people together and affects human emotion, whether it increased our survival or not.
References Balter, Micheal, “Seeking the Key to Music,” Science 306 (2004): 1120-1122, accessed December 10, 2011.  Zimmer, Carl, “The Brain,” Discover 31.10 (2010): 28-29, accessed December 4, 2011.