Some researchers say that multitasking can lead to decreased productivity and increased levels of stress. Others assert that some people are better at multitasking than others. So what does the latest research say about what happens to your brain when you try to do too much at once?

Multitasking is something we do every day without really thinking about it. It might be driving and listening to the radio, or talking on the phone and looking at Facebook. Multitasking means trying to do two things at the same time, which usually means switching between tasks, or not finishing one task before starting another.

The scientific study of multitasking over the past few decades has revealed important principles about the operations and processing limitations of our minds and brains. One critical finding to emerge is that we inflate our perceived ability to multitask – there is little correlation with our actual ability. In fact, multitasking is almost always a misnomer, as the human mind and brain lack the architecture to perform two or more tasks simultaneously. By architecture, we mean the cognitive and neural building blocks and systems that give rise to mental functioning. We have a hard time multitasking because of the ways that our building blocks of attention and executive control inherently work. To this end, when we attempt to multitask, we are usually switching between one task and another. The human brain has evolved to single task.

Key brain systems that determine our ability to multitask include the frontoparietal control network, dorsal attention network, and ventral attention network. These systems are studied using functional neuroimaging, which looks at brain activity while a person is performing a task, and by studying patients with focal neural injuries.

The brain has a hard time processing and completing two tasks at once because of the way the dorsal and ventral attention systems interact with the frontoparietal control network. When we start a task, the frontoparietal control network creates a goal representation that guides the dorsal attention network in selecting relevant information from external sensory stimuli or internal thoughts.

The ventral attentional network is more likely to be disrupted by competing streams of information when a person is multitasking. This is because there are multiple sources of information that can be considered relevant or irrelevant to the task at hand.

Switch Costs in Mind and Brain

We can examine the effects of multitasking by analyzing “task switch costs.” Task switch cost is a reduction in performance accuracy or speed that results from shifting between tasks. A lot of research has found that it is very difficult to avoid the behavioral costs of task switching- people usually take longer to complete a task and make more mistakes when they are switching between tasks than when they stay focused on one thing. Neuroimaging has helped us understand what is happening in the brain when people switch tasks.

Researchers used fMRI to study how people classified stimuli on one of three dimensions. They found that the frontoparietal regions of the brain were more responsive during switch trials than stay trials. When we switch from one task to another, our brain has to work harder to process the new information. This is because we have to constantly bring to mind the new task’s representation and then use it to allocate attention to information that is relevant to performing the new task.

How Multitasking Hampers Productivity

It is more productive to focus on a single task as opposed to multitasking. This is because our brains are not able to handle multiple tasks at once and we are only switching quickly from one task to another.

Multitasking Is Distracting

Those who multi-task may have a more difficult time focusing than those who complete one task at a time. This is likely because those who multi-task are constantly starting new tasks, effectively taking themselves away from their original assignment.

Some research suggests that those who work on multiple tasks at once are more distractible, and they may have trouble focusing their attention even when they’re not working on multiple tasks. However, other research shows that while there may be a connection between multitasking and distraction, that link is smaller than originally thought and varies quite a bit from person to person.

Multitasking Slows You Down

Even though it may seem like we’re able to handle multiple tasks at once, we’re actually working more slowly and less efficiently when we try to do multiple things at the same time. This is because switching from one task to another causes what psychologists call “task switch costs.” These are the negative effects that come from trying to do multiple things at the same time. We encounter task switch costs because it takes more mental effort to jump from one thing to another.

Focusing on a single task allows us to work on “autopilot,” which frees up mental resources. Switching back and forth between tasks bypasses this process and we tend to work more slowly as a result.

Multitasking Impairs Executive Function

Task initiation – this is where a person starts to think about and plan to perform a task. Task switching – this is where a person performs two tasks by alternating between them. Multitasking is managed by executive functions in the brain, which control cognitive processes and determine how, when, and in what order certain tasks are performed. There are two stages to the executive control process: task initiation, where a person starts to think about and plan to perform a task; and task switching, where a person performs two tasks by alternating between them.

1. Goal shifting: Deciding to do one thing instead of another
2. Rule activation: Changing from the rules for the previous task to the rules for the new task

It can take a few tenths of a second to move through these stages. This might not be a big issue when you are carrying out different tasks at the same time, like folding laundry and watching television. However, if you are in a situation where safety or productivity is key, for example when driving in heavy traffic, even small amounts of time can be crucial.

Multitaskers Make Mistakes

Research has shown that students who multitask in class tend to have lower GPAs, and if they continue multitasking at home, they often take longer to finish their homework.

A Spotlight on Media Multitasking

Given that media multitasking has become ubiquitous, with people engaging with or switching between multiple media streams, considerable interest has been attracted to this behavior. We know that American youth spend an average of 7.5 hours a day with various media and at least 29 percent of that time involves media multitasking. Data from other countries show a similar pattern, and the phenomenon extends to adults.

In 2009, Cliff Nass’s lab at Stanford developed the Media Multitasking Inventory (MMI) to quantify the extent to which an individual engages in this practice. The MMI asks individuals to report their hours of media consumption for each of 12 different media categories, along with the extent to which when engaged with one medium they were also engaged with each of the others. The MMI is highly reliable over a week, and moderately reliable over a one-year period.

Some scientists have been investigating the relationship between media multitasking and cognitive skills by looking at individual differences in attention lapsing while people are performing single tasks. Previous work has shown that there is a connection between fluctuations in eye tracking data and attention lapses during various tasks. They are now looking at how this relationship differs between people of different media multitasking habits.

One of the central challenges for researchers in the future is addressing the question of causality when it comes to the relationship between media multitasking and cognition. Another key challenge will be to determine which brain mechanisms may be underlying these relationships. For example, do differences in attention span or impulsivity between individuals lead to differences in their media use and multitasking habits? Or does engagement in media use and multitasking increase inattention and impulsivity? Are there any tasks where heavier media multitaskers might actually outperform lighter media multitaskers? How do the brain networks related to attention and control differ between heavier and lighter media multitaskers, and how does this relate to task performance? These are all questions that researchers are just beginning to explore––both in the lab and in the field. This highlights how psychological science and neuroscience are disciplines that are constantly evolving and growing, and how their discoveries can be used to address some of the fundamental issues faced by modern society.

Break the Multitasking Habit

If you feel like multitasking is negatively impacting your productivity, it is possible to make some changes that will increase your productivity and efficiency. The next time you find yourself multitasking, take a quick assessment of the various things you are trying to accomplish and work on one task at a time. Try to:

• • Limit the number of things you juggle at any given time to just one task. If you do need to work on multiple things at once, try to combine something automatic, like folding laundry, with something that requires more focus, like having a conversation.
  • Use the “20-minute rule.” Instead of constantly switching between tasks, try to fully devote your attention to one task for 20 minutes before switching to the other.
  • Batch your tasks. If you’re having trouble resisting the urge to check your email or engage in another distracting task, schedule a set time in your day to tackle it. By batching similar tasks together and setting a time to handle them, you can free your mind up to focus on something else.
  • Limit distractions. This may mean seeking out a quieter place to work, switching your phone off, and turning off notifications and alarms.
  • Practice mindfulness. Adding mindfulness to your daily routine may help you notice the times when you’re multitasking. Mindfulness can also improve your ability to focus and pay attention to one thing at a time.