Optimists tend to turn lemons into lemonade, and it turns out their sunny disposition can improve cognitive function. By asking ordinary people how to define optimism and what it means to them, media company SoulPancake unveiled the power it has to change one’s attitude and outlook on life. Passerbys on the street gave a variety of definitions, the responses varying from storytelling to lavish explanations trying to encapsulate the definition.

One respondent said it was important to "send out positive vibes." They believe that everything we send out into the world comes back to us, and that’s why optimism is so important. Dr. Martin Seligman, the father of the positive psychology movement and past president of the American Psychological Association, has a similar idea.

“The optimists, who are confronted with the same hard knocks of this world, think about misfortune in the opposite way. They tend to believe defeat is just a temporary setback, that its causes are confined to this one case.”

Historically, humans have been known to be optimistic in the face of adversity, and overtime, it has changed the way the brain processes information. In one study, 18 participants were asked to recall past events and to imagine a happy future while their brains were scanned. Those who thought positively of their past not only rated themselves as happier people, but they also felt more optimistic about the future. What's more is positive thinking stimulated the part of the brain responsible for happy emotions; it lit up more frequently during recall and imagination, while those who simply imagined a happier future experienced weaker activation in this same region.

Recalling happy memories makes it easier to see a future with happiness, which is what ultimately drives a person to adaptively react optimistically when they're handed those lemons.

Watch the video above for more on the power of optimism.