I'm trying to find a book I remember reading, one I'd like to re-read. I saw it probably decades ago. Basic premise is that earth has been stuck in a zone that somehow suppresses intelligence. When it leaves, everyday people go genius. I remember a throw away line early in the book with a scene about a kid who was toying with high mathematics and saying later that day he had reinvented calculus. I remember it causing chaos on Earth -- and I remember them doing some sort of space journey later in the book to test the theory that there was a zone of IQ suppression. I think I remember reading it as a small paperback. There might have been something about some animals becoming sentient as well, unless I'm confusing still another story. I don't remember the title or author. I'm thinking it had a cover possibly with a chimp riding an elephant into a farm or low-urban area or something -- unless my memory is mixing books.
This was long before Vernor Vinge's books.