Three studies are presented in support of a parsimonious interpretation of Fiedler's Least Preferred Coworker (LPC) Scale which has been consistently related to leader effectiveness. Two of the studies found that undergraduate psychology students who scored higher on the LPC scale expressed a more optimistic view of human nature. A field study then found that park employees who scored higher on the LPC scale were more willing to endorse park policies permitting increased personal freedom for youngsters in parks. These findings support an interpretation of LPC as a personality construct based upon confidence in human nature. (Author)