Nat. Neurosci. 11, 693–702 (2008); published online 18 May 2008; corrected after print 17 June 2008

In the version of this article initially published, the panels in Figure 1 were mislabeled. The correct legend should be 'Psychometric functions for the 29 experiments that included the 90° control are shown in e. Chronometric functions are shown in f'. This error has been corrected in the HTML and PDF versions of the article.