In the Intro Psych sensation and perception chapter, we often cover monocular cues. While it’s fine to think about how monocular cues help us perceive depth, I had never given much thought to what we would perceive if we lacked several monocular cues.
In Your Inner Fish, the author, paleontologist and anatomy professor Neil Shubin, writes
There is no field manual for Arctic paleontology. We received gear recommendations from friends and colleagues, and we read books-only to realize that nothing could prepare us for the experience itself. At no time is this more sharply felt than when the helicopter drops one off for the first time in some godforsaken part of the Arctic totally alone. The first thought is of polar bears. I can't tell you how many times I've scanned the landscape looking for white specks that move. This anxiety can make you see things. In our first week in the Arctic, one of the crew saw a moving white speck. It looked like a polar bear about a quarter mile away. We scrambled like Keystone Kops for our guns, flares, and whistles until we discovered that our bear was a white Arctic hare two hundred feet away. With no trees or houses by which to judge distance, you lose perspective in the Arctic (pg. 17).
This photo of Arctic Alaska can help you picture what Shubin and his colleagues were seeing—or not seeing. The caption says that those dark dots are caribou.
Looking at this tundra is not unlike looking at the sky, and the sky also frequently lacks monocular cues. When I see a speck with the sky as the background, if I perceive that speck as really close, then it’s a gnat. If I perceive it a little farther away, it’s a bird. If I perceive it really far away, it’s a plane. If I perceive the speck as being someplace between the bird and the plane, it’s Superman.
In Shubin’s case, the Arctic tundra didn’t give him many monocular cues to work with. Without a solid sense of distance, it’s difficult to determine the size of the object or critter.
After covering monocular cues, share with students the Arctic Alaska photo. Drag your browser so the description of the caribou is off the screen. Ask students to identify the dots in the photo. After all of the guesses are in, tell students that the dots are caribou. Ask students which of the monocular cues you covered can be seen in the photo, such as relative height. Ask students which ones are missing, such as linear perspective. The fewer distance cues we have, the harder it is to determine distance.
To close the activity, read students Shubin’s hare/bear paragraph. That will give you a leaping off point to talk about the ways in which our expectations can affect our perceptions. Shubin and his colleagues could have perceived the critter as a hare from the very beginning, but because polar bears were very much on their minds, a polar bear is what they all perceived. That is, until further evidence proved them wrong.