Multitasking: Does It Really Improve Productivity?

Research suggests only about 2.5% of people are able to multitask effectively. The remaining 97.5% only believe they can.

Defining multitasking

Multitasking is doing two tasks simultaneously, switching back and forth from one task to another, or performing multiple tasks in rapid succession. Examples include starting two projects at the same time, scrolling through social media whilst in a meeting, watching TV whilst responding to work emails, or having a conversation whilst checking your phone.

Multitasking compromises your ability to do all of the tasks well, and can impact your productivity by reducing comprehension, attention, and overall performance, leading to reduced efficiency, increased errors, increased time to complete tasks, difficulty tuning out distractions and mental blocks. Focusing on a single task is much more effective.

Time is lost to goal-switching and rule-activation

In a series of experiments in 2001, young adults switched between different cognitive tasks. For all tasks, participants lost time when they had to switch, and the more complex the task, the more time they lost. Time costs also increased with unfamiliar tasks, and they got up to speed faster when switching to tasks they knew better (Meyer, Evans & Rubenstein 2001). Their results indicated that task switching involves both goal-shifting and rule-activation stages, and that rule activation takes longer when switching to unfamiliar tasks.

Despite the detriment to performance, it is not uncommon for people to multitask in everyday situations, such as using a phone whilst driving, despite research demonstrating that driving performance is significantly degraded by phone conversations (Strayer & Drews 2007). Why does multitasking reduce performance? Since our brains lack the ability to focus on two things at once, in reality you are not doing tasks simultaneously — you are quickly shifting your attention and focus between tasks, creating a need to re-focus on the new task and distracting you from the original one.

Two types of multitasking: task switching and dual-task costs

Research on multitasking has shown there are two types, and both produce performance decrements: when tasks are performed in an interleaved manner (task-switching), and when two tasks are performed simultaneously (dual-task).

With task-switching costs, the performance deterioration is due to the effort involved in disengaging from one task and adjusting to another. This involves cognitive ‘task switch costs’ associated with deciding which task to change to and when (goal shifting), switching from the rules for the previous task to those for the new task (rule activation), and remembering where you got to. These costs increase with more complex or unfamiliar tasks.

Dual-task costs occur because of either a central processing ‘bottleneck’, task competition for a limited pool of attention, or competition for limited pools of specific processing resources. Dual-task performance requires concurrent and simultaneous task processing and motor responses (Strobach et al. 2018). These costs cause a deterioration of performance when the required attentional resources exceed the available ones — when participants have to handle very complex tasks, or several tasks that require attention from the same pool, structural interference impairs the simultaneous handling of those tasks (Wechsler et al. 2018).

Supertaskers

Research has found that a small percentage (2.5%) of the population can multitask successfully without a detriment in performance. These individuals perform in the top quartile in single-task conditions and excel at multitasking, showing a remarkable ability to successfully perform two attention-demanding tasks that 97.5% of the population cannot perform without incurring substantial costs in performance (Watson & Strayer 2010). It may be that supertaskers excel at the expense of other cognitive processing abilities.

Productivity slows by up to 40%

‘Task switch costs’ have been seen to slow productivity by up to 40% (Meyer 2001). Although each task switch might waste only a fraction of a second, repeatedly switching between tasks can add up to large amounts — multitasking may seem efficient but can actually take more time in the end and involve more error, which matters where productivity or safety are important.

A study found that individuals who report multitasking more frequently actually multitask less well than those who are less frequent multitaskers (Ophir et al. 2009). Frequent multitaskers have trouble focusing, filtering out irrelevant information, and are more distractible. A study of Stanford University students found high multitaskers had inferior attention, recall and task-switching abilities compared to low multitaskers. Allowing yourself to multitask will fuel any existing difficulties you have with concentration, organisation, and attention to detail.

Multitasking causes cognitive impairment, potentially long-term

Research by the University of London found that participants who multitasked during cognitive tests experienced IQ score drops of up to 15 points. The cognitive impairment from multitasking may not just be temporary. Researchers at the University of Sussex, UK, compared the amount of time people spend on multiple devices (such as texting whilst watching TV) to MRI scans of their brains, and found that high multitaskers had less brain density in the anterior cingulate cortex (ACC), a region responsible for cognitive and emotional control. The predisposition to multitask may be a function of this reduced brain density, rather than multitasking causing the reduction — but the results create awareness of the possibility that the way we interact with devices may be changing our brain structure and the way we think.

Persistent multitasking can raise cortisol levels, leading to stress and ultimately burnout. Multitasking in meetings and other social settings indicates low self- and social-awareness, both important emotional intelligence skills, and reduces comprehension and contribution.

Break the habit to improve your productivity and wellbeing

• The ‘20-minute rule’ — spend a minimum of 20 minutes on a task before switching.
• Use the 80/20 rule to identify the 20% of your tasks that produce 80% of your results, and resolve to focus on these.
• Prioritise the most important tasks for the day and tackle them first. This reduces anxiety, gives a sense of relief and accomplishment, and makes it easier to resist multitasking.
• Limit yourself to one task at a time, in blocks of concentrated time — you will be amazed at how much you accomplish.
• If necessary to do more than one task, combine something automatic (walking) with a cognitive task requiring focus (conversation).
• Limit distractions — turn off the phone, have a quiet work area, turn off notifications and alarms, especially in meetings.
• Batch similar tasks — for example, schedule and check emails and texts at the same time.
• Schedule ‘downtime’ (walk, exercise, listen to music) to allow your brain time to process information.

Conclusion

While multitasking may appear to be an effective way to handle numerous responsibilities, it ultimately hinders productivity and increases stress levels. By single-tasking and using time-blocking, prioritisation, minimising distractions, taking regular breaks, and practising mindfulness, we can combat the urge to multitask, maintain productivity and build our resilience.

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