Two suns in the sunset

   About a week ago I posted an entry about how easy it is for we humans to be fooled by what our senses tell us. Just a few days after that, I had a first hand experience that served to illustrate the point further.
   I was cutting the lawn in my back yard one evening after work. The sun was low to the horizon, and beaming across the yard strongly from my right side as I pushed the mower back and forth. Every once in a while, I would catch a movement out of the corner of my right eye. I'd turn and look in that direction, expecting to see my neighbour walking along the fence between our yards on his way to or from his own garden shed. There would be nobody there. It happened three or four times, and each time I would look up, expecting to see someone there, and there would not be anyone, or anything to see.
   Finally, a little bit weirded out by what was happening, I decided to figure out what it was I was seeing. I looked westward, over to my neighbour's lawn, shading my eyes against the sun that was minutes from sinking out of sight. As I moved back and forth a few steps, I laughed. What I saw, looking into the setting sun, was my own shadow.

   Sure, there was a shadow behind me as well, being cast against the wall of the house. It never caught my attention, and made me look up that way. Why not? Because that's where my brain was expecting the shadow to be. I'm sure movement on that side was catching my eye all the time, but my brain, deep in my subconscious, was saying, "that's nothing but your shadow," and I never took conscious notice of it.
   What my brain was not expecting, however, was that the sun, reflecting in one of the bedroom windows, would cast an equally strong shadow back the other direction. The very fact that there should not be a shadow there was what was causing me to look up every time it (I) moved. I'm sure an evolutionary anthropologist (if such a thing exists [it does, I checked]) would have an in-depth explanation having to do with a brain evolved for hunting/evading prey. Neither here nor there. The explanation doesn't change the fact. Our brains are wired to perceive things a certain way, and when things appear that don't seem to fit, we have strange experiences. We see ghosts, or angels, or neighbours.
   The effect was so strong that even after I had figured out exactly what was happening, I still could not stop myself from starting, and looking up every time I walked across the area in the yard that produced the doubled shadow. And it occurred to me that when we skeptics tell someone that we believe they have been fooled, they interpret that as an insult. They think we're telling them they're stupid.

   Nothing could be further from the truth. Our brains have been wired by millions of years of evolutionary pressures to respond to certain stimuli in certain ways, and there is nothing we can do about it. I can no more fail to look up at a shadow in the wrong place than I can prevent myself from being misdirected by the magician performing his sleight of hand. I can, however, understand what is happening, and by that understanding, discount false explanations. I know there wasn't really a lion waiting to devour me, and I know the magician didn't really make a coin come out of my ear.
   And I know the sugar pills won't really cure my illnesses, and I know that ghosts aren't really hiding in my closet.

Tags: skepticism, illusions, man my brain is wired!