(University of Bonn) Dr. Wolf M. Harmening from University Eye Hospital Bonn, together with American colleagues, studied color vision by probing individual sensory cells in the human eye. The results confirm that the photoreceptor cells of the retina are especially sensitive to colors corresponding to their visual pigments, even when stimulated in isolation. A new observation is that proximity effects play a key role: sensitivity varied depending on which cell classes were located in the immediate neighborhood.