So I’m sick, which basically sucks. However, sometimes there’s an upside. Maybe it’s the fever, maybe it’s boredom, but I have the strangest dreams when I’m ill.

So, in this dream I’m taking a test. It’s a specialized test, called a Change Blindness test. Normally, humans are pretty awesome at spotting small changes; we’re good with patterns and narrative, bad with things that aren’t. Change blindness is that strange exception to the rule, where our ability to spot change right in plain view is remarkably poor. This is some pretty interesting stuff because it gets down to the nitty-gritty concepts of perception. One of them is the notion of something called “Cross Modal Sensory Confusion”. That’s just a fancy way of saying we use more than one sense to commonly confirm our impressions. For instance, you might hear a very indistinct name such as Anne or Pam, but if you happened to be watching the person speak it, the specific lip movement would clue you in. But it goes a little further. Sometimes these senses inform each other so much that they actually ALTER your perception; that’s the confusion part. In the Anne/Pam example, if a video was substituted of a person making a pursed lip motion for “Pam” but the audio said “Anne” most people “hear” the word Pam. Another classic example is potato chips. For most people, the crunchiness of potato chips has less to do with their actual texture than it does with their sound. Scientists report that people who have their hearing muffled while eating chips consistently report the chips as less crispy. Cross Modal Perception and Synesthesia both are yielding interesting insights into human cognition.

In my dream I’m being asked to scan large fields of blinking dots with one eye and graphic drawings of items in the other, looking for specific changes. Normally, a small change on a uniform pattern of dots would be easy to spot, but the blinking complicates this. In my dream, this pattern reminds of me of the mechanical screen tones artists sometimes use to shade illustrations. The small dots are printed on clear film. What’s cool is, if you layer the film on top of itself, and angle it a bit, the uniform fields create patterns with themselves. Mathematics refers to this phenomena as a “Beat Frequency”. There are lots of examples of this in nature, but basically any wave crossing over another one can create a new, distinct pattern. A musician friend once demonstrated this to me by setting up two speakers on opposite sides of the room, each playing an individual undulating sound. In the middle of the room, where the two sounds intermixed, a third beat became audible. Anyway, these blinking dot patterns were giving me a headache. As I stared at a drawing of a bunny with one eye, the dots in the other, I would get a sharp pain in my head. But if I blinked either eye I found the headache went away. The two images, coming together in my head, were producing the pain and it occurred to me that some forms of pain might be a function of Cross-Modal Sensory Confusion and Beat Frequency.

Pain, in general, serves many useful functions. It informs us we’re being injured or something is wrong and we should take action –a hand on a hot stove or a toothache for instance. It can inform us we’ve pushed ourselves too hard and we should take it easy –sore muscles after an exercise, a sore knee or back. But chronic pain doesn’t serve this useful function. Unlike the transient nature of acute pain, chronic pain lingers and has a terrible impact on quality of life. Medical science has made enormous strides in repairing the underlying causes of acute pain, but when it comes to chronic pain, it’s as if we’re still in the dark ages. Statistics tell us 1/5 of the adult population suffers from chronic pain. It’s referred to as the “Silent Epidemic” and acknowledged as the most costly health problem in America, yet it remains commonly under-treated, misdiagnosed and misunderstood. Migraines, injury, lumbago, neuralgia, neuropathy, fibromyalgia, arthritis, disease, the list of things that make us hurt are endless. The list of effective treatments is frustratingly small.

In what I can only call a most curious coincidence, this morning’s RSS feed contained an NPR story called How Do You Amputate A Phantom Limb? In it, a doctor has an amputee patient with chronic pain in the phantom limb. The doctor treats the problem with a box and a mirror. The patient sees his other hand in the place where his amputated limb is and is instructed to practice clenching and unclenching it. To everyone’s surprise, the treatment works. The Doctor theorizes that the brain had not caught up to the reality of the missing limb and that the brain’s mental map of the body needed to be reconfigured. What he saw is what he became. Considering sight is a major factor in how we both relate to the world and our own bodies, it seems only logical that it could be exploited as an equally powerful cross-modal therapy. This can hardly be the only example of these principles at work in the real world.