You've been there: In the middle of a hot shower, the solution to a problem that had been particularly vexing suddenly becomes clear, like a light bulb going off overhead. But what quirk of your subconscious is responsible for that? What happens in our brains during that "ah-ha" moment — that shower-induced epiphany — and how does it differ from the type of creativity involved in writing a poem or inventing a new mathematical equation?Jonah Lehrer (How We Decide, Proust Was a Neuroscientist) explores those questions in his new book, Imagine: How Creativity Works (Houghton Mifflin Harcourt, $26, on sale Monday). Lehrer, 30, shared a few tips on how to boost creativity, even if you're no Picasso.Q: What is happening in our brains when we create? A: It's complicated. John Coltrane improvising a sax solo is not thinking in the same way as a graphic artist tinkering with a logo.Q: So, start with that ah-ha moment — that epiphany. What happens there?A: There is a sharp spike in activity in the part of the brain called the anterior superior temporal gyrus, in the right hemisphere right behind the ear. It's closely associated with things like inventing metaphors, hearing the punchline of the joke. It kind of confirms in an ironic way the cliché of the right hemisphere is central for creativity. Lots of neuroscientists have looked down at that truism as an oversimplification.Q: Why does it help to be relaxed?A: When we're not relaxed — when we're really vigilant — our attention is focused on the problem. That means we can't hear the quiet voice in the back of our head trying to tell us what the answer is.Q: Some of the most creative minds are altered through either drugs or illness. Are they better at unlocking that answer?A: A study came out last month that people actually solve about 30% more insight puzzles when they're slightly drunk. A couple of beers is relaxing. In terms of mental illness, that's complicated. No one would prescribe being bipolar in order to become more creative, but longitudinal study after study has found that there seems to be this correlation between some forms of mental illness — especially bipolar depression — and creative production.Q: You argue that brainstorming, as we typically define it, doesn't work.A: That surprised me. Brainstorming has become the most widely implemented creativity technique of all time. The first rule of brainstorming is "Thou shall not criticize." It feels good — we can all come into a room together and free-associate, fill up the white board. But people are much more productive when they work in groups following a very different set of instructions.Q: By being critical?A: This is a legacy of Steve Jobs, who advocated the practice of brutal honesty: He was president and CEO of Pixar during their formative years. They have a meeting every morning where they review the most recent footage of the film they're working on, and then they engage in what they call the "shredding process." They tear it apart. Over the course of four to five years of shredding, you end up with a really, really good animated movie. Criticism is built into their process at every step.Q: Has reporting this helped your own creativity?A: When I was stuck on a paragraph or figuring out how to structure a chapter, I used to chain myself to the desk. I'd stay up late. And I'd get up in the morning, and my fixes would not be fixes at all. Now I'm willing to take a walk or go play tennis to find some way to relax myself. When I'm stuck, I need to stop looking for the answer because the answer will only arrive once I stop trying to find it.For more information about reprints & permissions, visit our FAQ's. To report corrections and clarifications, contact Standards Editor Brent Jones. For publication consideration in the newspaper, send comments to firstname.lastname@example.org. Include name, phone number, city and state for verification. To view our corrections, go to corrections.usatoday.com.