(by Eileen Dombrowski, from OSC TOK blog April 15, 2014) “What you are seeing at the present moment is not a fresh snapshot of the world but rather an average of what you’ve seen in the past 10 to 15 seconds,” says a neuroscientist at the Massachusetts Institute of Technology. Jason Fischer, who conducted experiments while a PhD student in David Whitney’s lab at UC Berkeley, is lead author of a new study finding that what we see “may be a time-averaged composite of now and the past”.
The brain, in effect, smoothes over the fluctuations in what we perceive so that the world seems more continuous and stable. “The brain has learned that the real world usually doesn’t change suddenly, and it applies that knowledge to make our visual experience more consistent from one moment to the next,” says Fischer. He calls the averaging filter a “continuity field”.
David Whitney of UC Berkeley explains further:
“The continuity field smoothes what would otherwise be a jittery perception of object features over time. Essentially, it pulls together physically but not radically different objects to appear more similar to each other. This is surprising because it means the visual system sacrifices accuracy for the sake of the continuous, stable perception of objects.”
An article in Psychology Today points out the advantages: “Without the smoothing out of the rough edges, our perceptions of reality would become a hodge-podge of fragmented and surreal images.” Overall, our visual system is reducing the complexity of the environment by cutting out visual “noise”. We can look out through the rain and not see every falling raindrop; we see instead, through it, the road signs, the shop fronts, and the people. We are not hypersensitive to every moving shadow or slight movement around us. According to researchers, without the continuity field “faces and objects would appear to morph from moment to moment in an effect similar to being on hallucinogenic drugs.”
For TOK, this is one more example, along with familiar ones such as change blindness and inattentional blindness, to bring into classes on sense perception. Personally, I find this study quite delightful as another insight (no pun intended) into the gap between the world and how we perceive it. I never lament that sense perception as a way of knowing does not give us, at any scale, a perfect record of the world. What interests me is what knowledge we gain regardless, both through our senses and, as in this study in the human science of psychology, about our senses and how they work. Our ways of knowing (WOK) are the source of our areas of knowledge, but our areas of knowledge certainly illuminate how some of those WOK work. (And personally — I’m very glad not to have any more visual clutter to deal with!)
Yasmin Anwar, “Scientists pinpoint how we miss subtle visual changes, and why it keeps us sane”, UC Berkeley News Centre, March 30, 2014. http://newscenter.berkeley.edu/2014/03/30/continuityfield/
Christopher Bergland, “How Does the Brain Create a ‘Continuity Field’ of Vision?” Psychology Today, March 30, 2014. http://www.psychologytoday.com/blog/the-athletes-way/201403/how-does-the-brain-create-continuity-field-vision
Meeri Kim, “You might be seeing this on a 15-second delay: study”, Sci-Tech, The Sydney Morning Herald, April 6, 2014. http://www.smh.com.au/technology/sci-tech/you-might-be-seeing-this-on-a-15second-delay-study-20140406-zqrfp.html#ixzz2yJ5NrCni
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