New Jack Swing evolved in the late '80s, when urban contemporary soul artists began incorporating hip-hop rhythms, samples, and production techniques into their sound. Some songs simply had hip-hop beats, others had rapped sections and sung choruses, but the overall result was an edgier, more street-oriented sound that seamlessly blended both the melodic qualities of soul and the funky rhythms of rap. It paved the way for the '90s soul, where the dividing line between rap and R&B was frequently indistinguishable.