Figure 1.
Task design. a, Subjects were presented with a high-resolution image of a food item or a yellow square with a price shown above and an action independent gain/loss shown below. Positive values indicated a gain and negative values indicated a cost or loss. Subjects indicated with a button press whether or not they would pay the price above the image for the right to eat the food item shown and the end of the experiment. The gain/loss below the image occurred regardless of the subject's choice. b, Trials including only food items, only price, and only gain where included to help separate the values for GV, DV, and PE. Trial order, food items, price, and gain were randomized within subjects. c, Percentage of “yes” responses as a function of decision value. The y-axis represents the percentage of trials on which subjects responded “yes” to purchase the food item shown. The x-axis represents the decision value of the trial. Decision value was calculated as the amount the subject bid for the food item minus the cost for that food item in the current trial. Error bars represent SEM.
