Wish you had more faith in others? If you're young, sit tight. A new fMRI study found that the tendency to trust increases from adolescence to adulthood as activity ramps up in brain regions associated with understanding the mental states of ourselves and others (Social Cognitive and Affective Neuroscience, 2013).

But even if your teenage years are behind you, you can boost trust with positive emotions. Northeastern University's David DeSteno, PhD, found that people who played economic games in the lab tended to behave in slightly untrustworthy ways to maximize their monetary gain. But if they were made to feel a sense of gratitude before the game, they were less likely to cheat (Emotion, 2010).

Paul Piff, PhD, of the University of California, Berkeley, has begun exploring the link between trust and another positive emotion: awe. In not-yet-published work, Piff found that when people have an experience that inspires awe — something that makes them feel small, but part of something bigger — they become more communal, more cooperative and more trusting of others. So, go see the Grand Canyon, take in a symphony, visit the Sistine Chapel. Just hope you don't run into any con artists on the way home.

— Kirsten Weir