Everyone thinks they can multi-task. However, as reported by the California Department of Motor Vehicles (2009), based on a study by the National Highway Traffic Safety Administration (NHTSA), 80 percent of all car crashes involve driver distraction within three seconds of the crash. The primary distractions include cell phone use (texting and phoning), reaching for things within the vehicle, looking at things outside the vehicle, reading, and applying make-up.
Consistent with much of the recent literature on cognition and working memory, as well as visual and auditory stimuli, humans apportion finite cognitive resources to process auditory and visual stimuli on an “as needed” basis. However, as the demands increase, reaction time increases and accuracy decreases. Indeed, cognitive resources are limited, as is processing speed, working memory and individual ability.
Kemker et al (2009) report cognitive attention theory is based on a multidimensional attention-based system that allocates processing resources from a finite supply. Some tasks require minimal resources which can involve nearly or actually automatic processing (i.e., minimal) while others demand significant processing (i.e., controlled processing). The authors note that previous research has revealed the most demanding require the most attention capacity.
Further, three key variables impact both types of processing: (1) memory-load, (2) the nature of stimulus-response mapping, and (3) the amount of practice.
Kemker et al examined the effects of an ongoing cell phone conversation across a battery of cognitive tests with regard to response time and accuracy across auditory and visual cognitive arenas. Not surprisingly, when complex tasks are introduced involving working memory, lexical and form discrimination, controlled processing is required. Specifically, they determined that visual cognitive performance is degraded with simultaneous cell phone use. For example, while the visual cognitive task is simple, auditory distraction causes little impact. However, as the visual cognitive task becomes increasingly complicated, the effect of the auditory distraction increases.
For More Information, References, and Recommendations
California Department of Motor Vehicles (retrieved Nov 28, 2009) Driver Distractions – Don’t Be a Statistic.
Kemker BE, Stierwalt JAG, LaPointe LL, Heald, GR (2009) Effects of a Call Phone Conversation on Cognitive Processing Performances. Journal of the American Academy of Audiology. 20(9):582-287