premise: Backing vocalists provide vocal harmony to another singer.
hypothesis: Backing vocalists are singers who provide vocal harmony with the lead vocalist or other backing vocalists . In pop and country songs , backup vocalists may perform vocal harmony parts to support the lead vocalist . In hardcore punk or rockabilly , other band members who play instruments may sing or shout backup vocals during the chorus ( refrain ) section of the songs . Doo-wop . Doo-wop features vocal group harmony , nonsense syllables , a simple beat , sometimes little or no instrumentation , and simple music and lyrics .