Plate 36 from the chapter The muscles of Joy and Benevolence

Guillaume-Benjamin-Armand Duchenne de Boulogne was a French neurologist and photographer whose systematic documentation of facial muscle contractions established the foundations of modern expression studies. Working in the mid-19th century, he used electrical stimulation on living subjects to isolate and photograph specific muscular movements, creating a scientific archive that bridged physiology and portraiture. His 1862 publication 'Mécanisme de la physionomie humaine' combined daguerreotypes and engravings to map the relationship between muscular action and emotional expression, influencing both medical understanding and artistic practice. His methodical approach to the body's involuntary responses remains a cornerstone reference for neuroscience, psychology, and contemporary image studies.