Time preference
In economics, time preference (or time discounting, delay discounting, temporal discounting, long-term orientation) is the current relative valuation placed on receiving a good or some cash at an earlier date compared with receiving it at a later date. Time preferences are captured mathematically in the discount function. The higher the time preference, the higher the discount placed on returns receivable or costs payable in the future. One of the factors that may determine an individual's time preference is how long that individual has lived. An older individual may have a lower time preference (relative to what they had earlier in life) due to a higher income and to the fact that they have had more time to acquire durable commodities (such as a college education or a house).. As future is inherently uncertain, risk preferences also affect time preferences. A practical example: Jim and Bob go out for a drink but Jim has no money so Bob lends Jim 10 now, or I will give you 15 at the end of the month rather than $10 now. Present and expected needs, present and expected income affect one's time preference. In the neoclassical theory of interest due to Irving Fisher, the rate of time preference is usually taken as a parameter in an individual's utility function which captures the trade off between consumption today and consumption in the future, and is thus exogenous and subjective. It is also the underlying determinant of the real rate of interest. The rate of return on investment is generally seen as return on capital, with the real rate of interest equal to the marginal product of capital at any point in time. Arbitrage, in turn, implies that the return on capital is equalized with the interest rate on financial assets (adjusting for factors such as inflation and risk).