Figure 1.

Behavioral tasks. A, The desirability rating task. Successive screens displayed in one trial are shown from left to right with durations in milliseconds. Subjects had to rate the object featured in the video by moving a cursor along an analog scale. The object was taken as the goal of an action in the G condition but not in the NG condition. Each object had an identical, yet differently colored, counterpart with which it formed a pair. Within each pair, one object was featured in a G video and the other in an NG video. The two objects of a pair were always presented in the first and second halves of the same experimental session. Between the two versions of the task (A and B), the conditions (G and NG) assigned to the two objects were swapped. In the example illustrated, the green candy was the G object in version A but the NG object in version B, and vice versa for the yellow candy. To eliminate color preferences at the group level, half the subjects performed version A and the other half performed version B. B, The recognition task. Subjects had to select the “old” object, which meant the object that had been featured in the videos (either G or NG) shown during the rating task. Every choice contained one old and one “new” object. In the illustrated example, the correct answer would be green for the choice on the right and yellow for the choice on the left.