<Table> <Tr> <Td> </Td> <Td> This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations . Please help to improve this article by introducing more precise citations . (October 2015) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations . Please help to improve this article by introducing more precise citations . (October 2015) (Learn how and when to remove this template message) </Td> </Tr> <P> The cyclical theory refers to a model used by historian Arthur Schlesinger to attempt to explicate the fluctuations in politics throughout American history . Liberalism and conservatism are rooted in the "national mood" that shows a continuing shift in national involvement between public purpose and private interest . Each of these cycles includes a phase of dominant public interest, a transition phase, and a phase of prevalent private interest . </P> <P> Schlesinger defined these to be "self - generating and autonomous". They begin in the mentality of the masses, rather than creations of influential individuals of a time period . Leaders or politicians are representations of the "mood", chosen to express the voice of the majority . Shifts in the national mentality are initiated when discontent with present conditions over time drives Americans to pursue a new trend that promises to satisfy the interest of the masses . This discontent, described by Schlesinger as "inextinguishable", drives the cycles of change in national politics . </P>

Who gave the cyclical theory of socail change