Being in a relationship for a long time changes the way you see the world. It also changes you. Everything from how you act to the way you think changes in ways you might not even notice.
And according to Joshua Wolf Shenk, the author of "Powers of Two," these changes are also what enhances a different kind of thought process — a shared mind, so to speak — that allows couples (romantic or not) to come up with more creative solutions to problems than they'd ever think up on their own.
Here are some of the signs psychologists have observed that they say characterize such a shared mind.
