Some people meet, fall in love and get married right away. Others can spend hours in the sock aisle at the department store, weighing the pros and cons of buying a pair of wool argyles instead of cotton striped.

Seeing the world as black and white, in which choices seem clear, or shades of gray can affect people's path in life, from jobs and relationships to which political candidate they vote for, researchers say. People who often have conflicting feelings about situations—the shades-of-gray thinkers—have more of what psychologists call ambivalence, while those who tend toward unequivocal views have less ambivalence.

High ambivalence may be useful in some situations, and low ambivalence in others, researchers say. And although people don't fall neatly into one camp or the other, in general, individuals who tend toward ambivalence do so fairly consistently across different areas of their lives.

For decades psychologists largely ignored ambivalence because they didn't think it was meaningful. The way researchers studied attitudes—by asking participants where they fell on a scale ranging from positive to negative—also made it difficult to tease apart who held conflicting opinions from those who were neutral, according to Mark Zanna, a University of Waterloo professor who studies ambivalence. (Similarly, psychologists long believed it wasn't necessary to examine men and women separately when studying the way people think.)

Now, researchers have been investigating how ambivalence, or lack of it, affects people's lives, and how they might be able to make better decisions. Overall, thinking in shades of gray is a sign of maturity, enabling people to see the world as it really is. It's a "coming to grips with the complexity of the world," says Jeff Larsen, a psychology professor who studies ambivalence at Texas Tech University in Lubbock.