Whereas individual differences in the degree of time discounting have been found to be meaningfully related to important outcome variables,
some researchers have reported evidence that individual differences in time discounting cannot be generalized among domains – a phenomenon
called domain independence. However, the Participant × Domain interaction and its importance in relation to the main effect of domain
have never been studied. In the present paper, generalizability analysis is used for the first time to separate the sources of variance in time discounting
choices (into differences between participants, domains, magnitudes, delays, and their interactions). Results show that the most important
source of variance is the Participant × Domain interaction. Differences between participants and between magnitudes were also important.
Thus, several sources of variance in time discounting choices should be acknowledged. Most importantly, people seem to differ in their
reaction to domains.