During WWII, brain scientists grew concerned at the fact that while WWII pilots looked at their screens, they would sometimes miss signals that German planes were flying overhead. One of these scientists, Alan Mackworth, a professor at the University of British Columbia, worked with Donald Broadbent, who volunteered for the Royal Canadian Air Force at 17, to do important research in the field.

A decade later, Anne Treisman studied psychology at Cambridge during a time the field dominated at the time by B.F. Skinner and behaviorism. She was interested in cognitive psychology, and what could “overload the brain” (103). At Oxford, she ran an experiment where two separate audio feeds were played in the right and left headphones and subjects had to focus on only one and repeat it. The conclusions of this study were that the brain’s “attention filter is very effective,” but “our filter is not a total block” (104).

Treisman’s research clarified that our attention travels in two directions, which tend to impede one another: top-down (our brain’s intention to pay attention to a specific input wills our attention in its direction) and bottom-up (incidental stimuli catch our senses and are then funneled to the brain for further analysis and processing).