In the early 1800s, phrenology was a popular method of psychology. Phrenology is the theory that the bumps on a person’s head can foretell a person’s personality. Using this theory, many early psychologists were able to distinguish characteristics in a person’s personality to assist parents with raising children or helping someone find a husband. A certain research method to reach their hypothesis was the use of case studies. Over time, psychologists were able to figure that areas on the head that had distinctive bumps were related to specific behaviors. For example, referring to the textbook, thieves had larger bumps above the ears. To develop this theory I believe that, in that time period, coincidently people who stole supposedly had these distinctive bumps and soon psychologist came to believe that anyone with the same bumps had tendencies to steal. Case studies from earlier records could have showed such bumps on thieves and therefore was assumed related.
When phrenology was first being developed, I’m sure the founder was keeping detailed descriptions on record for later reference. Over the years, phrenologists looked back to these case studies to use for themselves on their patients and thus the findings were always relevant. They were never argued or debated at that time because phrenologists assumed they were fact. But with recent studies and new technology, the theory was laid to rest in