As of the current version of Dwarf Fortress (0.47.03), in Adventure Mode, an adventurer can pick up books and read them, to gain experience in the Reader skill and learn about the topic the book concerns. After they do so, they usually gain a positive thought that indicates they "learned" the topic. For example, my adventurer read a book called "Did Waxing and Waning Falter?" and got this thought:
He is interested after learning about the theory that the sun moves around the world.
Which seems to imply that my adventurer learned something pretty horribly incorrect about astronomy, but at least he learned something, I suppose.
However, as far as I can tell, there is no noticeable in-game impact for an adventurer "learning" new topics like this, or gaining new information about the world by reading books. According to the DF Wiki entry on Literary Forms:
All forms have been found, but currently the precise mechanics behind learning knowledge or receiving a change in values from them is still unclear.
Right now, adventurers can only learn new art forms and academic knowledge from books. If an adventurer reads a book of a given literary genre that requires an academic topic to unlock, this will teach the academic topic, so if an adventurer without academic knowledge reads an autobiography, they'll learn the autobiography topic.
So, my question is: is there any in-game effect at all for an adventurer learning new topics from books? (In the current, 0.47 version of the game?)