According to Professor Paul Smith of Warwick University, Cézanne's method of looking with rapt attention at his subjects caused visual anomalies. The sitters in his portraits (such as Madame Cézanne in a Yellow Chair) seem to have mask-like faces because he concentrated on small areas of facial detail and didn't allow his mind to consider the face as a holistic whole. In Still Life with Apples and a Pot of Primroses (c 1890), the leaf on the right-hand side doesn't have a stalk, indicating that an unbroken visual fixation on the area has resulted in Troxler's Fading.
