Phrenology (from Ancient Greek φρήν (phrēn) 'mind', and λόγος (logos) 'knowledge') is a pseudoscience which involves the measurement of bumps on the skull to predict mental traits. It is based on the concept that the brain is the organ of the mind, and that certain brain areas have localized, specific functions or modules. It was said that the brain was composed of different muscles, so those that were used more often were bigger, resulting in the different skull shapes. This led to the reasoning behind why everyone had bumps on the skull in different locations. The brain "muscles" not being used as frequently remained small and were therefore not present on the exterior of the skull. Although both of those ideas have a basis in reality, phrenology generalized beyond empirical knowledge