Meaning of Inward and Outward Interest in the context

I am not able to understand the the context in which inward and outward are being used. (I know inward for introvert, and outward for extrovert), but what does inward interest and outward interest mean here ?

"You have both introverted and extroverted tendencies – at different times and different occasions. Your interests are turned in about equal proportions, both inward and outward."

Book – Word Power by Norman Lewis