A friend and professor is confident her granddaughters are able to multitask without any significant negative impact on their performance. She observes them using the computer and cell phone while doing homework and listening to music or watching television. They are star students in demanding schools.

I told her I have my doubts. I suspect anyone’s performance, when splitting the brain’s attention, is inevitably lower than her native aptitudes would allow if focusing on a single task. Perhaps my friend’s granddaughters are geniuses (I’m sure she would agree) whose performance would be even better if focusing.

Scientific American reports research that validates my suspicions.

the heavy media-multitasking group had difficulties, compared to the low media-multitasking group, when asked to ignore information that was in the environment or in their recent memory. They also had greater trouble relative to their counterparts when asked to switch rapidly between two different tasks. This last finding was surprising, because psychologists know that multitasking involves switching rapidly between tasks rather than actually performing multiple tasks simultaneously. … In contrast, people who do not usually engage in media-multitasking showed a greater ability to focus on important information.

The article goes on to say so-called multi-taskers treat all information as equally important, while single-taskers focus on information relating to their current objectives. The first is a bottom-up attention strategy and the second is top down, meaning multi-taskers let their information environment drive their attention while single-taskers’ attention is governed by higher-level cognitive, goal-oriented processes. In our information glutted world, some bottom up attention is useful, however. As we increasingly augment our overtaxed minds with external systems and tools (reminder alerts, alarm chimes, sticky notes, checklists, calendars, task managers, etc.), we benefit from being able to notice when these systems offer useful information. As one who tends to get hyper-focused on certain tasks, I benefit from my Mac reminding me that another hour has passed. Without my cell phone’s alarm feature, I would have missed many a meeting. I have even outsourced some reminding tasks to my wife, who will send an email to my office to remind me of a dental appointment.