Miss Jan De Jong is orderly, neat, fairly quiet, and shy. She enjoys reading in her spare time and belongs to a social club that includes three librarians, nine real estate agents, and eight social workers. A tendency to conclude that Jan must be one of the three librarians would illustrate the powerful influence of:

Answer: Introversion.

Explanation: Introverted people have a great sense of responsability and are very hardworking people, they do everything seriously and are constant in the activities they carry out. They strive to perform perfectly their daily tasks and everything related to their profession. They like to lead an orderly life. They are calm, and very perfectionist people.