To see how mood affected vision, the researchers had people self-report their moods before and after looking at images while undergoing a fMRI brain scan. The Images had a central face with houses behind it. To get them to focus on the face instead of the houses, they were asked to determine which gender the face was. Meanwhile, the brain scan monitored what parts of their brains were being activated by the task.
Both happy and grim people saw and processed the image of the face in the center, which showed on the fMRI as activation in the fusiform face area (FFA, in green). But when it came to the seeing the whole picture, the participant's mood had a strong effect. The researchers found that those who said they were in good moods had more brain activity, particularly in the parahippocampal place area (PPA, in blue), a portion of the brain used to process places. In other words, they noticed the houses in the periphery, too, while the gloomy participants didn't.
"Under positive moods, people may process a greater number of objects in their environment," said Taylor Schmitz, lead author of the study, in a press release. "Good moods enhance the literal size of the window through which we see the world." In the end, it seems, it's the optimists who get to see the big picture and are more in tune with the world around them.
While the scans look convincing, as with any study, more research is needed to understand exactly why or how mood impacts our brain activity and vision. It's possible that being in a better mood, while widening our field of view, also leads to us getting easily distracted. Bad moods, perhaps mediated through stress hormones, allow us to focus better.
But, for now, if someone tries to bring dampen your mood by saying you're unrealistic, you can tell them to stop being such a pessimist. And if they say that they're not "pessimistic," they're just "seeing things how they are" - correct them.
Schmitz, T., De Rosa, E., & Anderson, A. (2009). Opposing Influences of Affective State Valence on Visual Cortical Encoding Journal of Neuroscience, 29 (22), 7199-7207 DOI: 10.1523/JNEUROSCI.5387-08.2009