Phrenology Head Coasters. Phrenology is the study of the bumps on our heads to determine personality traits. This practice was very popular in the 1800's; buy not so much today. In honor of this now defunct "science" we proudly offer the Phrenology Coaster Set which shows the areas to assess bumps througout the development ages. This set is excusively designed by the artist Kirstin for The Psychology Shop.