An empirical, 21st century evaluation of phrenology

Phrenology was a nineteenth century endeavour to link personality traits with scalp morphology. It has been both influential and fiercely criticised, not least because of the assumption that scalp morphology can be informative of the underlying brain function. Here we test this idea empirically, rather than dismissing it out of hand. Whereas nineteenth century phrenologists had access to coarse measurement tools (digital technology then referring to fingers), we were able to re-examine phrenology using 21st century methods and thousands of subjects drawn from the largest neuroimaging study to date. High-quality structural MRI was used to quantify local scalp curvature. The resulting measurements were compared against lifestyle measures acquired on the same cohort of subjects. We were careful to match a subset of lifestyle measures to phrenological ideas of brain organisation, in an effort to evoke the character of Victorian times. The results represent the most rigorous evaluation of phrenological claims to date.