In a notable study of power conducted by social psychologists John R. P. French and Bertram Raven in 1959, power is divided into five separate and distinct forms. They identified those five bases of power as coercive, reward, legitimate, referent, and expert. This was followed by Raven's subsequent addition in 1965 of a sixth separate and distinct base of power: informational power. Whereby, this is to be considered "power" in social influential situations.