Idiot Brain by Dean Burnett

a basic yes/no detection test, people typically fall apart trying it. Some people can do two simultaneous tasks if one is something they’re very adept at, such as an expert typist doing a math problem while typing. Or, to use an earlier example, an experienced driver holding a detailed conversation while operating a vehicle.
    Attention can be very powerful. One well-known study concerned volunteers at Uppsala University in Sweden, 14 where subjects reacted with sweaty palms to images of snakes and spiders that were shown on screen for less than 1/300th of a second. It usually takes about half a second for the brain to process a visual stimulus sufficiently for us to consciously recognize it, so subjects were experiencing responses to picturesof spiders and snakes in less than a tenth of the time it actually takes to “see” them. We’ve already established that the unconscious attention system responds to biologically relevant cues, and that the brain is primed to spot anything that might be dangerous and has seemingly evolved a tendency to fear natural threats like our eight-legged or no-legged friends. This experiment is a great demonstration of how attention spots something and rapidly alerts the parts of the brain that mediate responses before the conscious mind has even finished saying, “Huh? What?”
    In other contexts, attention can miss important and very unsubtle things. As with the car example, too much occupying our attention means we miss very important things, such as pedestrians (or, more importantly, fail to miss them). A stark example of this was provided by Dan Simons and Daniel Levin in 1998. 15 In their study, an experimenter approached random pedestrians with a map and asked them directions. While the pedestrians were looking at the map, a person carrying a door walked between them and the experimenter. In the brief moment when the door presented an obstruction, the experimenter changed places with someone who didn’t look or sound anything like the original person. At least 50 percent of the time, the map-consulting person didn’t notice any change, even though they were talking to a different person from the one they’d been speaking to seconds earlier . This invokes a process known as “change blindness,” where our brains are seemingly unable to track an important change in our visual scene if it’s interrupted even briefly.
    This study is known as the “door study,” because the door is the most interesting element here, apparently. Scientists are a weird bunch.
    The limits of human attention can and do have serious scientific and technological consequences too. For example, heads-up displays, where the instrument display in machines such as airplanes and space vehicles is projected onto the screen or canopy rather than read-outs in the cockpit area, seemed like a great idea for pilots. It saves them having to look down to see their instruments, thus taking their eyes off what’s going on outside. Safer all round, right?
    No, not really. It turned out when a heads-up display is even slightly too cluttered with information, the pilot’s attention is maxed out. 16 They can see right through the display, but they’re not looking through it. Pilots have been known to land their plane on top of another plane as a result of this (in simulations, thankfully). NASA itself has spent a lot of time working out the best ways to make heads-up displays workable, at the expense of hundreds of millions of dollars.
    These are just some of the ways the human attention system can be seriously limited. You might like to argue otherwise, but if you do you clearly haven’t been paying attention. Luckily, we’ve now established you can’t really be blamed for that.
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    * Some scientists have called this finding into question, arguing that this staggering number of smell sensations is more a quirk of questionable math used in the