Table 2.

Likely possible combination rules for the subjective values of two options

BOLD Combination Rule	Value
“Sum”	SV1 + SV2
“Larger-Later”	SVL
“Later Minus Sooner”	SVL − SVS
“Chosen”	SVC
“Chosen Minus Unchosen”	SVC − SVU
“Right” or “Left”	SVR or SVL

The superscript on SV is omitted here for clarity, since the combinations could apply to any subjective value function (Eqs. 1–4). The subscripts refer to how the two options are distinguished. Further possible combinations are listed in Supplemental Table S1 and are used in Supplemental Figs. S1 and S2.