Figure 32: Rire naturel par la contraction volontaire des deux grands zygomatiques et de l'orbiculaire palpébral inférieur

Duchenne embarked on the first scientific, systematic exploration of the physiology of human facial expression and hoped, through photographs of the experiments, to teach artists how to portray those emotions. Here, he has photographed a subject’s natural smile and described the muscles creating it. In subsequent photographs, he used an electrode to contract one of the muscles that convey that same emotion.