Imagine this: you're sitting on your front porch, reading a book. It's a bright and sunny day, the world is very calm and peaceful around you. You're enjoying the feel of the breeze on your skin when, suddenly, a truck noisily speeds past your house, and you are overwhelmed with the scent of bacon.

Or, you could be sitting on your front porch, reading a book, and the same truck speeds by, and you are suddenly overwhelmed with the color red.

For some people, this crisscrossing of senses is a reality, and it's called synesthesia.

Synesthesia is the condition in which an afflicted individual will find certain involuntary responses to stimuli of a specific sense. Chromesthesia, for example, is a type of synesthesia causing strong associations between the hearing of sounds and the seeing of colors. Other types of synesthesia associate visual mappings of numbers or calendars when computing maths. In more extreme cases, people are able to experience stimuli that they witness other people experiencing (imagine seeing someone being patted on the back, and feeling it yourself).

Millen Alley, a freshman at the University of Oregon, has been experiencing synesthesia for her whole life.

Millen experiences both chromesthesia and spatial sequence synesthesia, specifically the visualization of time (more on that later).

"It's different for everyone," she says, "Like, I see colors when I hear, taste or feel...some people hear sound and taste things. I'm definitely visual in all aspects." Additionally, when she hears or reads words, she can directly see the words as if they were text in front of her.

She describes the alphabet as colorful, and her mind associates each letter with a color. A is red, B is green, etc. For smaller words, like "cat," for example, the colors are distinguishable from each other, but for longer words, like "distinguishable," the whole word tends to be colored one shade. It's the same for numbers, except the color is instead determined by the first digit (2 is purple, all the 60's are red, the 100's are white).

"When I see noise, the color is muted," she says, "It's not like a projection. It's very much in my head. Kind of like a blob...It's not a hallucination...but loud environments or annoying noises mess with my vision. Too many sounds at once make it harder to focus."

Another unique aspect of Millen's synesthesia is the visualization of time, which she describes as being one big wheel she can see in front of her, representing a clock or calendar. As time goes by, she begins to see the wheel at different "angles."

"Like, right now, I'm seeing the wheel from the angle of January. Or, I can also see it from the angle of Monday, or 8:00."

For most of her life, she believed that this was how everyone experienced the world. It wasn't until eighth grade when she was watching a video of Romeo and Juliet, when she noticed something was different.

She noticed that the Montagues wore blue while the Capulets wore red. "That's odd," she said to a friend, "because Montague is supposed to be red." Her friend had no idea what she was talking about, but for Millen, the word "Montague" had been red her entire life. She finally learned what synesthesia was in her freshman year biology class, and made the connections herself.

Since then, she has been diligently researching the topic in an effort to learn more about herself and other people like her.

There is no scientific explanation as to what causes the phenomenon. It is believed that it stems from the crisscrossing of synapses in the brain, but otherwise, research has found nothing.

The American Psychological Association suggests that 1 in 2000 people may be synesthetes, experiencing one or more aspect of the condition.

Millen sees her synesthesia as an advantage, and utilizes it in her everyday life for memorization and organization. All her classes are color coded, and she can easily remember words through color patterns. "I've never looked into seeing a neurologist," she says, "It's just an added benefit in my life, why look for a doctor?"

People who experience synesthesia live life like everyone else, just through a different lens."It's very uncommon," she says, "People think you're crazy when you start talking about it. It's pretty hard to grasp."

Millen doesn't know a lot about synesthesia, nor does anyone else. Many more years of research will be needed to fully distinguish what causes it. But for her, and for the many other people who experience it, it has become an enhancement to her everyday life. It's what makes her unique, and she's proud of that.