Figure 3

Illustration of tasks A and B, which assess respectively visual and time discrimination capacities. (A) For task A, at each trial, the subject was asked to compare the size of the food stimulus (food picture in color) to that of its devalued counterpart (same image in grayscale), and to answer the following question: “Which image is the biggest?” by pressing the left or the right button (arrow key of the standard computer keyboard) when respectively the first or the second image was considered as the biggest one. Geometric figures (in a range of colors close to that of food images) and their respective devalued counterparts (in grayscale) were used as controls. For further details see Methods. (B) For task B, at each trial, the subject was asked to compare the duration of presentation of the food stimulus (food picture in color) to that of its devalued counterpart (same image in grayscale), and to answer the following question: “Which image has the longest viewing time?” by pressing the left or the right button (arrow key of the standard computer keyboard) when respectively the first or the second image was estimated as having the longest time of presentation. Geometric figures (in a range of colors close to that of food images) and their respective devalued counterparts (in grayscale) were used as controls. For further details see Methods.