Multitasking is not a new phenomenon. Many of us (especially women, apparently) are effortlessly able to complete two or more things at once. Recently however, an unprecedented type of multitasking has become commonplace. On a daily basis, we interact with multiple screen devices teeming with endless incoming information, be they emails, social network notifications, news alerts, or text messages. Multitasking when using technology at work and at play has become the norm.
Whilst the input may seem infinite, our attention system is not: we just cannot process everything at once. Multitasking might seem like an efficient way to complete tasks, but research indicates that using a computer to chat simultaneously with friends whilst at the same time reading increases the time taken to read by 22-59% even after the additional time taken to instant message is accounted for.1
Laptops, iPads, and smartphones may well be becoming ubiquitous in and outside of the classroom, but it seems that multitasking during learning2,3 and studying4 reduces academic performance. When students were given simple Google, YouTube, or Facebook search tasks that occupied a third of class time, they scored 11% worse on a subsequent test compared to students who didn’t multitask during class.2
Frequent multitaskers may process information differently. It turns out that frequent multitaskers are better at multisensory integration, such as using apparently irrelevant auditory information to complete a visual task.5 However, by the same token, frequent multitaskers are more distractable.6,7 A pioneering study divided students into frequent and infrequent multitaskers, and then gave them distraction tasks.6 Students looked at shapes, numbers, or letters, but the goal was to remember something about just some of the images on the screen and to ignore the others. High multitaskers seemed unable to ignore the shapes they were told to ignore, and were unable to filter out what wasn’t important to that particular task. In all cases the low multitaskers outperformed their frequent multitasking counterparts. Other studies8,9 have failed to replicate these findings. However, these conflicting findings may be due to differences in the task given to the participants or differences in the criteria used for defining heavy and light multitaskers. There is also the possibility that a subset of “super-taskers” exists for which multitasking may have no negative impact or may even improve cognitive performance.10
Interestingly, depression and social anxiety12 and poorer wellbeing13 are also associated with multitasking. Multitaskers are also more impulsive and perform more poorly on measures of fluid intelligence.14 Crucially, we don’t know if multitasking causes these or if people with these attributes multitask more. We also need more research on different types of multitasking. Research has found that multitasking using Facebook and texting while studying is negatively predicative of overall GPA, but emailing, talking on the phone and instant messaging are not related to GPA.4 In any event, frequent multitaskers are showing differences in brain structure: new research shows they have smaller grey matter density in a particular area of the brain called the anterior cingulate cortex (ACC).11 The ACC is involved in functions ranging from autonomic regulation of blood pressure and heart rate, to more sophisticated, vague and above all diverse processes from empathy to decision making to empathy.
As with much of the research into technology and the brain, we don’t know yet whether people with smaller ACC are more likely to multitask due or whether higher levels of multitasking causes the ACC to shrink. Moreover we cannot extrapolate from the anatomical changes to the behavioural ones seen with multi-tasking. But the fact that the effects of screen-based multi-tasking can be seen at both the level of the physical brain, and in performance, should perhaps encourage at least a brief moment of undistracted reflection.