In the article “Low-Serotonin Levels Increase Delayed Reward Discounting in Humans” by Nicolas Schweighofer, Mathieu Bertin, Kazuhiro Shishida, Yasumasa Okamoto, Saori C. Tanaka, Shigeto Yamawaki, and Kenji Doya, which appeared on pages 4528–4532 of the April 23, 2008 issue, the color legend in Figure 2 did not match the conditions of the experiment. In the bar graphs, the left bars (gray) should represent the depletion condition, the middle bars (black) should represent the control condition, and the right bars (white) should represent the loading condition. The correct Figure 2 is printed here.
