Filtering

I am listening to The Great Ideas of Psychology on CD, narrated by Daniel Robinson, a professor at Georgetown University.

I have spoken in previous posts of the brain's imperfections in perception and memory. Professor Robinson summarized the case nicely: we constantly filter the information coming to us, so it should not be a surprised that, at times, we cannot later accurately restate what truly happened.

The filtering occurs at a physical and cognitive level. At the physical level, our eyes will not respond to light with a wavelength of infrared or longer, nor to with a wavelength of ultra-violet or shorter. Our eardrums will not mimic vibrations in the air occurring more frequently that 20 thousand times per second nor less frequently than 20 times per second. There are many chemical compounds in the air we label "odorless", but in fact they are detectable, just not by human noses.

Even with these limitations there is still a lot of information impinging on us at all times. We would not be able to function if we attempted to process all of it. The human brain, over eons of natural selection, has become adept at focusing on just those things we need to maximize survival. Our cognition is so adept, in fact, that we approximate it as perfect, so that cases like The Invisible Gorilla become fascinating.