Daniel Gregory Mason,
From Grieg to Brahms: Studies of Some Modern Composers and Their Art
“ He who persistently smiles will end by being cheerful, and a moderate amount of sighing or groaning will make any one melancholy. Above all, the imitation of vocal movements, such as we all go through at least incipiently when we hear melody, and the «keeping time» that strong dance-music so irresistibly prompts—these actions very noticeably set up in us their appropriate states of feeling. We not only imitate the lip motions and throat contractions of a persuasive speaker or singer, but doing so fills us with the emotion that prompts his utterance. ”
