A short note about the "Jean Requin illusion"

In this article I report the results of a study designed to test the generality of an illusion first noted by Jean Requin. This illusion is based on earlier results obtained by Frey et al. (1981) who after having modified the position of the woman's head in Picasso's painting "The lovers" showed that this modification led to illusory changes in the woman's facial expression, even though only the head posture had been altered. When I showed this modified version of the painting to Jean Requin he noted that the facial expression of the man also seemed to have changed.