This paper analyzes an Ak-type endogenous growth model under non-constant discounting,
assuming both naïve and sophisticated consumers. For both type of consumers
an isoelastic utility with an intertemporal elasticity below one guarantees observational
equivalence under exponential and non-constant discounting, but rejects strong equivalence
(identical overall impatience does not leads to identical growth rates). Further,
polices aimed at increasing productivity of the economy are less growth-enhancing than
typically predicted by the literature with exponential discounting.
