This data supplements the article: Witzel, C., & Gegenfurtner, K. R. (2016). Categorical perception for red and brown. Journal of Experimental Psychology: Human Perception & Performance, 42(4), 540-570. doi:10.1037/xhp0000154 The Excell-file with the data includes 3 sheets: Sheet 1 (jnd): JND data from Figure 4.a of the above article. - columns = 20 test colours. - rows = 14 observers. Sheet 2 (rt): Response time data from Figure 6.a of the above article. - columns = three kinds of colour pairs (AB, BC, & CD) and the location of the target (left vs. right). - rows = 15 observers. Sheet 3 (er): Error rates from Figure 6.b of the above article. - columns and rows as in sheet 2.

This research was funded by the Deutsche Forschungsgemeinschaft (#SFB TRR 135), and CW was financially supported by a German Academic Exchange Service (DAAD) postdoctoral fellowship and by J. Kevin O'Regan's ERC Advanced Grant "FEEL" (#323674).