A library is a good location to test reading comprehension for titles, authors, books they have read, types of reading materials they enjoy. Texting on a smart phone can also be used to identify their ability to spontaneously compile words to form sentences beyond routine phrases. Types of games or reading material enjoyed will give you an insight into what classes of information reaffirms their sense of identity.
Time
The person is aware of the passage of minutes and may use an internal clock to judge about 15 minutes.