Fig. 2.

Behavior. A: postchoice rating of the low- and high-value items selected in choice 2. B: postchoice rating of the items selected in choice 2 as a function of the number of choice alternatives. For A and B, the data were averaged over all 18 participants. C and D: frequency with which participants chose the choice option as a function of the amount of money offered in the monetary amount option in choice 1. These data were averaged over all 18 participants and are displayed separately for low-value (C) and high-value trials (D). In both trial types, participants' preference for the choice option in choice 1 increased with the number of items that would be available to choose from in choice 2. Intersection of dotted horizontal lines and data fitted with a sigmoid function reflects monetary amount equivalents used in further behavioral analysis and for regression against brain activity. Monetary amount equivalents correspond to the estimated monetary amount at which choice and money would each be chosen 50% of the time. E and F: monetary amount equivalents as a function of the number of items that would be available to choose from in choice 2. The monetary amount equivalents were averaged over all 18 participants and are displayed separately for low-value (E) and high-value trials (F). In both trial types, monetary amount equivalents increased with the number of choice alternatives.