Table 1.

Key Terms

Term	Definition
Expected value	The worth of an option as a function of its attributes (in delay discounting, reward magnitude and delay to the receipt of that reward).
Hyperbolic discounting	Tendency to discount delayed rewards in inverse proportion to the length of the delay.
$k_{indifference}^{item}$	Discount rates that correspond to the indifference point for a given item consisting of a smaller immediate and a larger delayed reward options (Methods, equation 1).
k subject	Subject-level discount rate that captures individual preferences for smaller, immediate, versus larger, delayed rewards.
Valuation consistency, β	A degree to which choices are sensitive to the relative expected values of the available options. This parameter is analogous to the inverse temperature of the softmax choice function (Methods, equation 4).