Final answer:
Completing two tasks simultaneously requires divided attention, which can lead to inattentional blindness. This attention demand is evidenced by tasks that distract us to the point of missing obvious events in our environment.
Step-by-step explanation:
Completing two tasks at one time requires divided attention, a form of attention that involves processing multiple streams of information simultaneously. Inattentional blindness can occur when we're focused on intense activities, meaning we might miss other obvious occurrences in our environment. Tasks that require significant attention can increase energy demands on the brain, potentially leading to fatigue, stress, or anxiety. This high level of focus is needed when learning new skills, such as a foreign language or commuting to a new place. Over time, some activities become automated, allowing us to perform them with less cognitive effort, transitioning from attentive to automatic processing.
An example of divided attention in action is the ‘selective attention test’ by Daniel Simons and Christopher Chabris. During this test, many participants fail to notice an unexpected event, specifically a person in a gorilla suit walking through a basketball game, because they are focused on counting the passes of the ball—a clear demonstration of inattentional blindness. Furthermore, tasks like vigilant monitoring or recognizing signals in noise are attention-intensive and require mental resources that are limited.