Seeing the world through rose-colored glasses may be more than just a cliché. Recent fMRI data from the University of Toronto raise the possibility that your mood can influence actual visual perception. So who sees better: the optimist or the pessimist?

When it comes to self-appraisal and being in touch with reality, a healthy dose of pessimism is not a bad thing. It has long been known that while depressed individuals suffer from a wide range of problems, they have, in general, a much more accurate self-assessment than do normally functioning adults.

However, it's not always a good thing to see ourselves accurately. Delusions of being better than we actually are help us deal constructively with the world. That is one of the reasons why depressed individuals are often inactive: they don't see the point of engaging.

But by having a false sense of self-worth, we overcome the inaction and are productive once more. Thus, it's evolutionarily adaptive to lie a bit to ourselves about what we are worth. The vast majority of people do this every single day.

Not so when it comes to vision. People who are in a good mood literally take in more of the world. As professor Adam Anderson, one of the study’s authors, puts it, “When in a positive mood, our visual cortex takes in more information, while negative moods result in tunnel vision.”

This could be a self-perpetuating cycle: if you’re in a good mood, you actually notice more than your neighbor in a foul mood. What you see can make you appreciate life more, or encourage a better perspective, reinforcing the initial positive emotion and, consequently, expanding vision.

Have you ever noticed, for instance, that when you’re happy, everything seems somehow more vibrant, and there are suddenly things that you never noticed before? Conversely, if you’re in a bad mood, you notice none of this and instead remain focused on the cause of your negative emotions, thus reinforcing both the mood and the impaired visual processing.

Perhaps such a physiology-based explanation can shed light on general dispositions, or help understand why it is that people sometimes get stuck in cycles of depression. Also, it could endorse a clinical approach involving visual stimulus to prompt a wider view and subsequent happier mood.

Of course, such therapeutic applications are mere conjecture at this point, but it is intriguing to think of the myriad implications that a wider or narrower view of our surroundings could hold for our everyday perceptions.