Why Existence of Hyperbolic Discounting is Not Evidence of Investor Irrationality?

A number of researchers (Rubenstein, 2000; Thaler, 1981) have shown that investors have a preference for higher short-run returns, and a declining rate of time preference. Such preferences have been cited as evidence for both investor irrationality and short-comings of the discounted utility model proposed by Samuelson (1937). The purpose of this paper is not to dispute the existence of hyperbolic discounting, but rather to argue that such a discounting process is perfectly rational, especially for a budget constrained investor making a choice between two not-very-uncertain outcomes