In What’s Mine is Yours, Rachel Botsman argues for the spread of a “collaborative” form of this behavior to replace 20th-century individualistic forms. Interdependence inherent in this behavior is described by James Duesenberry’s “demonstration effect.” An intertemporal theory of this behavior was updated with discounted utility theory to form a “smoothing” (15[1])effect (15[1])in Franco Modigliani’s (*) life-cycle hypothesis. This behavior’s marginal propensity is subtracted from 1 (10[1]-5[1])in formulas (10[1])that calculate the fiscal multiplier. A variable that quantifies this behavior is typically the largest factor in calculating GDP and positively correlates with disposable income. A key tenet in Keynesian economics holds that governments can end recessions through this behavior’s “deficit” type. For 10 points, name this variable often contrasted with saving. ■END■ (10[1])