Another negative effect that cell phones impair is mental concentration while driving. Drivers have their minds focused on the task ahead of them and their full attention on the road. So when a person is conversing on the phone, their attention is divided as they try to multitask by talking and driving at the same time. In an article written by Nathan Seppa, the originator of “divided attention,” he points out that David Strayer, professor of psychology, and his team studied to understand what weakens drivers when they talk on the phone. They conducted an experiment with drivers to see the effects of different distractions in relation to each other. Strayer's team accompanied the drivers and assigned them different distraction tasks while they kept their eyes on the road to evaluate the effects. The team's results revealed that one of the most distracting tasks was talking on a cell phone, which led to a significant drop in driver performance. Typical tasks that drivers must perform regularly, such as observing traffic changes, looking in mirrors and watching for pedestrians, have been reduced overall (Seppa). Few people can hold a conversation and drive at the same time without some inconvenience. Another disadvantage of the focus on the person was “unintentional blindness,” described by Simons, as “looking at something and not seeing it” (Seppa). So a person talking on the phone may end up not seeing an object, whether it's a car, a stop sign, or a pedestrian right in front of them. Many experiments have been conducted by professionals to understand how "unintentional blindness" can affect a person's perception, but one notable professional, Simmons, tested this concept: Middle of paper..... . ch Transportation Institute provides insight into cell phone use and distracted driving. " Virginia Tech News. Virginia Tech Transportation Institute, Virginia Tech, 2009. Web. April 9, 2014. Piper, Andy. "Lawmakers Try to Limit Cell Phone Limits for Drivers." Telegraph – Herald. February 1, 2010. ProQuest. Web. April 11, 2014. "California Safety Laws." see. Distraction: theory, effects and mitigation. Boca Raton, FL: CRC Press, 2009. E-Book Collection (EBSCOhost Web, March 28, 2014). Zyla, Tim. “PennDOT Tackles Distracted Driving. » 2013. ProQuest. Internet. March 28. 2014.