From Edward Mendelson, The Things That Matter: What Seven Classic Novels Have to Say about the Stages of Life (2006):
In the early nineteenth century the most up-to-date and modern psychological science was phrenology, the pseudoscience that identifies your emotional and moral character by mapping the bumps on your skull, in much the same way that more recent pseudoscience traces your voluntary actions back to the unchosen, involuntary workings of selfish or altruistic genes. A university chair in phrenology was established at Glasgow in 1845, and Charlotte Bronte, like most of her contemporaries, took it for granted that phrenology was valid science; Jane Eyre is conscious of her "organ of veneration" when Helen Burns recites Virgil, and observes on Rochester's forehead "an abrupt deficiency where the suave sign of benevolence should have risen," and Rochester observes in Jane "a good deal of the organ of Adhesiveness." But for Charlotte Bronte, phrenology was merely a familiar feature of her intellectual landscape. Marian Evans [George Eliot] took it far more seriously as a new instrument of knowledge that called for her active participation in it. At the time she was translating Strauss's Life of Jesus, she arranged to have a full phrenological analysis made of herself, based on a plaster cast of her cranium, and the preparations for the analysis included shaving her head.