Introduction

In the fall of 1986 I asked each of the authors of this volume to come to the Fourth International Conference on Event Perception and Action in Trieste, Italy and participate in a symposium entitled “Absolute versus relative theories of lightness perception.” I was not surprised that each of them agreed; the logic that connected our work seemed obvious to me, and I assumed it was equally obvious to the others as well. I discovered only much later that this was not true. It seems the others were puzzled at the composition of the group, one or two regarding it as crazy. In the meantime we all met in Trieste and had an unusually stimulating week together.