Mental processes of multitasking are not well understood and probably few of us look at this from the perspective of flying. We scan and interpret instruments relative to our current flight profile, review the approach, respond to ATC, and—oh yeah—fly the airplane. We might redirect our scan or perform other tasks based on sights, sounds, even smells, or trigger events like passing a waypoint or reaching an altitude.
That mental interrupt process involves storing the details of the existing event for later, gathering the details of the new event, then processing those details and performing that task. When the ongoing interrupted events or tasks exceed a certain number—typically five to seven—the mind has a difficult time making the needed transition. Confusion can impede processing and we can become mentally paralyzed.
