I was initially dismissive due to the obvious title, but I'm glad I read it. Lots of great information in here, including the famous Gorilla experiment. Lots of pointers to interesting brain stuff.
Yes, the filtering systems of the brain are amazing, and the Invisible Gorilla experiment is particularly fun!
Another striking experiment I learned of in neuroscience courses shows how deep it goes. A particular setup of electrodes can show how a sound stimulus is processed by successive nodes in the auditory processing areas of the brain. When hooked up to a cat near a metronome, for example, the traces from different electrodes tracking different auditory processing nodes, will spike in sequence, like an earthquake wave passing various seismic stations at different locations on the ground.
The wild thing is that when a mouse is now brought into view of the cat, the cat's attention becomes so focused that the metronome traces disappear -- the cat's brain filters them out at such a low level that the cat doesn't just ignore the metronome, it literally no longer processes the sound at a low level -- as far as the cat's brain is concerned, the experimenter might as well have turned off the metronome.
I've often thought that a similar mechanism underlies people forgetting names right after and introduction. A new introduction creates at least some level of anxiety in most people (we want to make a good first impression for the sake of social acceptance), and so we turn our attention inward on ourselves just like the cat turns its attention on the mouse. The result is that attention to the outside world is reduced and the name or other details are forgotten. This holds true for any anxiety-provoking experience. Memory is severely degraded, to the point of complete black-outs of truly traumatic experiences. It could also be the mechanism that causes depersonalization-derealization (DPDR), which is a reaction to anxiety. The sensory experience of the outside world becomes attenuated and one feels detached from reality.
I've had anxiety issues for over a decade and I'm well acquainted with DP/DR. I'm intrigued by your articulation of why it may be an adaptive trait for humans. Do you have any references to research that pursues this line of inquiry?
