First European Conference on Visual Perception, Marburg 1978 (with C.R. Cavonius, J. Mollon,
I. Rentschler) 

Annual Meeting of the German Color Center, Freiburg 1983 

International Conference in Memory of Richard Jung on the Neurophysiological Foundations of Visual Perception, Badenweiler 1987 (with J.S. Werner) 

COGNET-Graduiertenkolleg, Bochum 1993 (with W. Ehrenstein) 

Gehirn und Gestalt, Hanse-Wissenschaftskolleg, Delmenhorst 1999 (with G. Roth, S. Stiehl) 

Wie das Gehirn sieht, Summer Academy of the Studienstiftung des Dtsch. Volkes, St. Johann, Italy, 1999 (with H.-D. Hofmann, J.S. Werner)