Hot coffee is hand and bag slung over my shoulder, I get onto the train. The ride from Montclair, NJ to Penn Station, NY is just short of a half an hour. I have made this ride many times before and will make it many times in the future. The cues are all familiar – the smell of the coffee and the seat in the back, right hand side of the train car. The train always boards with between five and ten minutes until departure, and it is during this short time frame that I make the all too familiar mistake. I look over my shoulder out the window to my right and see that our train has left the station…. Or has it? No, no it’s the train next to us.
I’ve never been sure why I make this same mistake over and over again, but reading this week that errors of perception often are a result of top-down processing I began to understand why. In top-down processing, your beliefs, cognitions, and expectations drive the pattern recognition process. It essentially states that if you are expecting to come across a certain pattern, then you are focusing your attention on looking for evidence consistent with that pattern, and not processing whatever is in view. (www.usc.com)
The knowledge I have about mechanized means of transportations tells me that in order to get from the starting point to the destination, then whatever vehicle I am riding in has to move to take me there. Additionally, all my experiences support that knowledge. So, it makes sense that as I sit in that same train seat, I am waiting for my train car to start moving. And that when there is movement, my vision doesn’t take into account right away that the tracks underneath remain in the same place or that I do not feel any movement, I have weeded out that information as it is inconsistent with my train leaving.
My experience is also a good example of the theory of unconscious inference, which states that some of our perceptions are the result of unconscious assumptions we make about our environment. (Goldstein, 58) When I see movement out of the train window, I don’t think about it, I just assume that it is because my train is starting to head down its tracks. It never takes a long time to realize that mistake (maybe because have made at least a thousand times) but still for a couple of seconds each time I get disoriented.
Top down processing is a clearly a very important part of being able to correctly perceive our environment and make sense of our surroundings. Generally, top down processing, leads to many correct assumptions about the things going on around us, however my experience is an example of how it sometimes backfires. They are called heuristics and not laws, right? (Goldstein, 62) Maybe next time I sit down in my seat, with my coffee and I notice movement outside, I’ll remember to think twice and carefully examine what is really moving… or maybe I’ll try choosing a different seat!
WORKS CITED
Goldstein, B. E. (2011). Cognitive Psychology Connecting Mind, Research, and Everyday Experience, Third Edition. Belmont, CA:Wadsworth.
Notes of Top-Down & Bottom-Up Processing. (n.d.) Retrieved from February 1, 2014 from http://www.ucs.louisiana.edu/~cgc2646/LRN/TOPDOWN.htm
Top-Down Train Ride
I know exactly the mistake you mean. Your explanation, the breakdown of it, the train has to move to take you to your destination is a brilliant explanation. Many a time, have I been sitting in my car on a hill, sloping up or down, it doesn’t matter, and a car next to me starts rolling in my peripheral vision as I gaze at the red light. I push my foot harder onto the brake, because for that half a second I think I am rolling. Like you, my vision doesn’t take into account that the light to which my eyes are fixed isn’t getting any closer or further from me, just that there is motion where there should (or should not) be. I think a part of this mistake is also that we are used to the feel of the movement of our transportation, it doesn’t register in that short span of time that the feel isn’t there.
An Abstract statement by Whitney D. at NCBI.nlm.nih.gov, supports what you and I have both indicated, and even takes it one step further: “A second experiment showed that when subjects were unable to identify the direction of a physically present motion stimulus, the apparent locations of other objects were still influenced.” Which takes us to the times we have been at an amusement park on a ride that distorts our perception of direction, perhaps the slow-to-mid speed cups that spin and move backwards…usually…but sometimes forward.
http://www.ncbi.nlm.nih.gov/pubmed/17154779