 This work, often conducted by economic theorists and analytical philosophers, suggests ultimately that the assumptions or axioms above are not completely general and might at best be regarded as approximations.Alternative theories of human action include such components as Amos Tversky and Daniel Kahneman's prospect theory, which reflects the empirical finding that, contrary to standard preferences assumed under neoclassical economics, individuals attach extra value to items that they already own compared to similar items owned by others.Under standard preferences, the amount that an individual is willing to pay for an item (such as a drinking mug) is assumed to equal the amount he or she is willing to be paid in order to part with it.