What does a large forehead mean in phrenological term?

The term phrenology is a term used to describe a pseudoscience that uses the size and shape of the skull to understand a person's character and abilities. Although there is no scientific basis for phrenology, it was popular in the 19th century, and was particularly popular in the United States. According to the principles of phrenology, a large forehead is often associated with qualities such as intelligence, reason, and insight.