We talk with bassist and songwriter Stanley Clarke, who boasts a career spanning 40 years and work on over 40 albums. The four-time Grammy Award winner was the backbone of jazz-fusion band Return To Forever in the 1970s. His most recent album, “The Stanley Clarke Band: UP,” was released in 2014, with a new version of his hit tune “School Days.” Clarke is now on tour, and performs at the Variety Playhouse in Atlanta Thursday at 8 p.m. Then, a new study from the University of Georgia links