Craniology is the study of the shape and size of the skull, particularly in relation to human diversity and its supposed implications for intelligence, behavior, and character traits. This pseudo-scientific practice emerged in the 18th and 19th centuries as part of broader attempts to categorize humans into distinct races based on physical characteristics, often reinforcing racial stereotypes and biases. Craniology played a significant role in promoting scientific racism, as it was used to argue that certain races were inferior or superior based on cranial measurements.