Charles Darwin was so captivated by his musician wife Emma's daily piano playing that her music influenced at least two key evolution theories formulated by the British naturalist, according to a new paper.
The paper, which has been accepted for publication in the journal Endeavor, suggests that Charles Darwin's home life, and particularly his love of music, played a larger role than many might think in shaping his work, such as his groundbreaking book "On the Origin of Species," authored 150 years ago.
"The long-term marital dance of Emma and Charles Darwin was set to the routine beat of an almost daily piano recital," according to Julian Derry, who told Discovery News that "music was central to home life and a panacea after a hard day's work, or often when not feeling well."
Derry, a researcher in the Institute of Evolutionary Biology at the University of Edinburgh, made the determination after studying Emma Darwin's diary, Darwin family correspondences and other documents. These show Emma and Charles "were rarely separated" after they married in 1839, he said.
The family even conducted experiments together on earthworms, with Emma playing loudly to see if the worms would react. They didn't, so Charles concluded worms "are completely deaf."
Charles' appreciation of music began before marriage when, as a Cambridge student, he used to time his walks in order to hear anthems issuing from King's College Chapel.
"This gave me intense pleasure, so that my backbone would sometimes shiver," he later wrote.
The naturalist frequently lamented his own lack of musical skills, which seemed to heighten his admiration of Emma's playing, usually enjoyed while he reclined on a living room sofa. Derry believes such evenings contributed to Darwin's theory of sexual selection.
In "The Descent of Man," Darwin wrote, "I conclude that musical notes and rhythm were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex."
Derry added, "Darwin's idea was that the organs for sound production in early humans could have been precursory to more complex verbal communication, namely language."
More recent studies, such as research on Neanderthals, appear to support this theory.
Derry also claims Darwin's observation of his 10 children and their varied musical abilities contributed to his theories on mechanisms for inheritance, which were described in "On the Origin of Species."
After marveling how his daughter Annie shared his mother's aptitude for the piano, Derry said Darwin wrote, "If we suppose any habitual action to become inherited — and I think it can be shown that this does sometimes happen -- then the resemblance between what originally was a habit and an instinct becomes so close as to not be distinguished."
According to Randall Keyes, a conservationist who is the great great grandson of Darwin, Annie was her father's favorite child, making her death at the young age of 10 all the more difficult.
Peter Bowler, a professor of anthropological studies at Queen's University, Belfast, and a Darwin expert, said Keyes was "not the first to notice that following Annie's death, Darwin became much less tolerant of traditional Christian beliefs and far more open to the view that nature was a scene of relentless struggle and suffering."
He added, "No more would Darwin compromise with the past: natural theology was dead for him, and he would develop his theory in a way that would throw down the gauntlet to those who were still trusting in the old platitudes."
Emma, however, survived her husband, and continued to play piano for him until he died at home in 1882.