What is the main reasoning behind multitasking impairing driving ability?

Multitasking can significantly impair driving ability primarily due to the overload of the central executive process, which is responsible for managing and coordinating cognitive tasks. When a driver engages in multitasking—such as talking on the phone, adjusting the radio, or eating—the brain is forced to split its focus among several tasks. This division of attention taxes the central executive, which can lead to a decline in the driver's ability to process critical information related to driving.

This overload of the central executive process results in slower reaction times and decreased situational awareness, both of which are vital for safe driving. The brain struggles to effectively prioritize and respond to stimuli in the environment, increasing the risk of accidents. Unlike a situation of sensory deprivation where there may be an absence of stimuli, or reduced cognitive load, where fewer tasks allow for better focus, multitasking complicates the cognitive landscape to a point where performance suffers. Thus, the central executive's overload from multitasking is the key factor impacting driving safety.