Driving Under the Influence…of a Cell Phone

The United States wireless industry is fully taking advantage of its recent big break, with colorful ear buds and trendy covers being hauled in by the dozen. Over thirty states have outlawed driving with hand-held cell phones and have replaced them with hands-free devices instead [1]. Studies, however, continue to prove that the hands-free substitution is much less beneficial than lawmakers, phone companies, and myriad other groups wish. Today’s fast-paced lifestyle lends itself to mastery of the art of multitasking, and the recent burgeoning of the media industry deserves much of the credit for the introduction of a more complex form of multitasking: continuous partial attention (term coined by Linda Stone in 1997), or CPA [2]. Unfortunately, increased reliance on CPA might not be very advantageous to drivers…or anyone, really.

What is CPA?


The subtle difference between ordinary multitasking and CPA lies in the motivations behind each [2]. Traditional multitasking equally prioritizes simple tasks that necessitate minimal cognitive operation, like drinking coffee and filing papers, with the motivation to accomplish more in less time. In slight contrast, CPA is based on a different state of awareness, similar to that of a crisis. Keeping a threshold level of attention on a single higher priority task, the brain attempts to gather as much outside information as possible from all surrounding stimuli [2]. The reason for this is that most surrounding stimuli are forms of media, constant sources of information—CPA is basically a form of media multitasking. For example, while a person’s main focus is on dinner, he or she is also trying to take in the scene on TV while flipping through the newspaper and checking email on the trusty smart phone companion. The unconscious motivation of CPA is to collect as many details as possible, not just to expedite tasks and save time [2].

Phone conversations while driving uniquely qualify as CPA


A fine line separates ordinary multitasking from CPA, no doubt, but there are three major reasons that a cell phone conversation in a car qualifies as reliance on CPA. First, it naturally becomes a high-priority task since it is an interaction with another person. Second, the driver is trying to take in information constantly, from the cell phone, the road, and any other stimuli in the environment. Third, the conversation is a constant source of new information, completely independent of the driver’s environment and not necessarily able to stop or adjust with driving conditions. Other possible disturbances such as a conversation with a passenger or the radio can easily stop or be turned off according to the needs of the driver. That makes driving while on the phone much more risky.

Hands-free devices don’t solve

Though lawmakers would like to think so, it does not make a difference whether a driver is holding a cell phone or using a Bluetooth device. Once a conversation is in session, the driver loses attention to it, not motor skills. The National Safety Council reports drivers impaired by cell phone conversations, whether hand-held or hands-free, twice as likely to miss traffic signals and react slower [3]. Brain imaging research at Carnegie Mellon demonstrates that driving while just listening to a cell phone (responding not included) reduces occipital lobe activity, as well as parietal lobe activity associated with driving, by 37 percent [4].

Reliance on CPA adversely affects mental ability

Not only is CPA dangerous while driving, but it can also have negative long-term effects on cognition. Stanford University conducted a study in 2009, comparing the mental abilities of habitual “media multitaskers” to infrequent ones, and made some unsettling discoveries about people who are constantly splitting their attention. Contrary to popular belief, regular media multitaskers performed worse than their counterparts on three different tasks, including concentration, memory organization (of simple items like letters, numbers, and shape orientations), and, more shockingly, switching focus from one task to another. The researchers concluded that media multitaskers—reliant on CPA, by definition—were easily and continuously sidetracked by irrelevant information [5].

According to Stone, the very nature of CPA activates the fight-or-flight mechanism in conjunction with it, treating every event—from checking emails to answering phone calls at work—like an emergency. Stone asserts the harms of a constant adrenalized state: slower, poorer performance on tasks, accompanied by a completely unnecessary and avoidable cascade of stress hormones that bring about attention- and stress-related disorders [2].

Despite evidence imploring reconsideration of current driving regulations, it may be long before lawmakers quit trying to falsely legitimize the use of handheld devices. After all, alcohol and automobiles had coexisted for at least twenty years before DUI was even acknowledged as dangerous. CPA impairs both mental ability and attention, and hands-free devices are not a valid solution. Though preservation of basic cognitive skills outside the car is a personal choice, there is still much that the law can do to better protect lives.


  1. Governors Highway Safety Association. “State Cell Phone Use and Texting While Driving Laws.” Washington, D.C.: Governors Highway Safety Association; [updated 2011 January; cited 2011 January 10]. Available from: http://www.ghsa.org/html/stateinfo/laws/cellphone_laws.html.
  2. Stone L. Bloomberg, “Continuous Partial Attention—Not the Same as Multi-Tasking.” Business Week; [updated 2008 July 24; cited 2010 October 18]. Available from: http://www.businessweek.com/business_at_work/time_management/archives/2008/07/continuous_part.html.
  3. U.S. Department of Transportation, Bureau of Transportation Statistics, Transportation Statistics Annual Report 2001. 2002 [cited 2011 January 10] 298:[155] Available from: http://www.bts.gov/publications/transportation_statistics_annual_report/2001/pdf/entire.pdf.
  4. Spice B. Carnegie Mellon University. “Carnegie Mellon Study Shows Just Listening
To Cell Phones Significantly Impairs Drivers: Brain Imaging Reveals Drivers Are Distracted Even if They Don’t Talk.” Pittsburgh, PA: Carnegie Mellon University; [cited 2011 January 10]. Available from: http://www.cmu.edu/news/archive/2008/March/march5_drivingwhilelistening.shtml.
  5. Gorlick A. Stanford University. “Media multitaskers pay mental price, Stanford study shows.” Stanford, CA: Stanford Report; [updated 2009 August 24; cited 2010 November 7]. Available from: http://news.stanford.edu/news/2009/august24/multitask-research-study-082409.html.

Apurva Tandon is a sophomore at the Harker School in California.