The Consumption Function, The Permanent Income Theory and The Life Cycle Theory. It is clear that the consumption function is a very important concept in the study of macroeconomics, yesterday, today, and into the future. This study will probe further into theories of the consumption function, with particular attention given to the permanent income theory and the life cycle theory. 8 pgs. 13 f/c. 4b. Pages: 8 Bibliography: 4 source(s) listed Filename: 2803 Consumption Function Theory.doc Price: 71.60