If fiction then vocabulary does not imply if not fiction then not vocabulary.
The truth value of the inverse doesn't follow the truth value of the original statement.
Right. My anecdote isn't directly contrary evidence, but it is a contrary hint. If reading fiction were an excellent way to build vocabulary, I'd expect to see acquaintances who avidly read fiction to have larger vocabularies than acquaintances who don't read fiction. This is not what I see.
It might be that my acquaintance sample is weird. It might be that avid fiction readers fluidly express themselves with simple words where the less well-read resort to obscure vocabulary. But (over)generalizing from my personal experience, I (somewhat) suspect that people's vocabulary has less to do with the fiction they read than is usually assumed.
Although my 8-year-old son likes his teacher, he is frequently bored at school. He attends a high quality suburban public school in the United States. He has a lot of traits in common with LessWrong readers, and we would like advice for what he can do to counter his boredom. Many of you must have found grade school more or less tedious. What were your coping strategies?