This is how everything has been programmed. At what time the character is going to wake up, leave its home, go to work, stop at a conbini convenience store to buy some food, goes outside again to catch a bus etc.
At noon, there was a lunch break and the NPC usually brought its lunch and ate it at the park. Also, the NPC's behavior would change depending if it was a week day or weekend.
This intelligent process contained a lot of data. This is explained by the fact that even if you were not even close the NPC, it was still leading its own life, like working.