Brightness of Affective Pictures 1 RUNNING HEAD: Brightness of Affective Pictures Brightness Differences Influence the Evaluation of Affective Pictures Daniël Lakens Eindhoven University of Technology Daniel A. Fockenberg VU University Amsterdam Karin P. H. Lemmens, Jaap Ham, & Cees J. H. Midden Eindhoven University of Technology In press, Cognition & Emotion 7588 words KEYWORDS: affective pictures, emotions, brightness bias, IAPS, color psychology. Author Note: We thank Dik Hermes for valuable assistance with MATLAB programming. Correspondence can be addressed to Daniël Lakens, Human Technology Interaction Group, IPO 1.24, PO Box 513, 5600MB Eindhoven, The Netherlands. E-mail: D.Lakens@tue.nl.