The Heresy of Multitasking

The Heresy of Multitasking


In an ever-more saturated media environment, media multitasking is becoming an increasingly prevalent phenomenon, especially among the young. Although we think we are doing several tasks at once, multitasking has been shown to be a powerful and diabolic illusion. Substantial evidence has shown that multitasking affects performance characterized by response delays and errors, which result from an attentional problem in cognitive processes. Researchers have examined the immediate effects of multitasking, and of media multitasking in particular, on memory, learning, and cognitive functioning. However, it is unknown whether and how chronic heavy multitaskers process information differently than individuals who do not frequently multitask (viewing multitasking as a trait. This issue seems especially pertinent in light of evidence that human cerebral processing has difficulty attending input information and simultaneously performing multiple tasks. Data suggest that heavy media multitaskers are distracted by the multiple streams of media they are consuming, or, alternatively, that those who infrequently multitask are more effective at allocating their attention in the face of distractions.

Neuro-physiology of Multitasking

It takes more energy to shift your attention from task to task. It takes less energy to focus. When people think they are multitasking, they are actually switching from one task to another very rapidly and each time, there is a cognitive cost. That also means that people who organize their time in a way that allows them to focus are not only going to get more done, but they will be less tired and less neuro-chemically depleted after doing it. Daydreaming takes less energy than multitasking so the natural intuition of back and forth between focusing and daydreaming helps to recalibrate the brain. Multitasking does not. Perhaps more important, multitasking by definition disrupts the kind of sustained thought process usually necessary for problem-solving and for creativity. In multitasking, we unknowingly enter an addiction loop as the brain’s novelty centers become rewarded for processing new stimuli, to the detriment of our pre-frontal cortex, which wants to stay on task.

Asking the brain to shift attention from one activity to another causes the prefrontal cortex to burn up oxygenated glucose, the same fuel they need to stay on task. And the kind of rapid, continual shifting we do with multitasking causes the brain to burn through fuel so quickly that we feel exhausted and disoriented after even a short time. We have depleted the nutrients in our brain. This leads to a compromise in both cognitive and physical performance. Staying on task is controlled by the anterior cingulate and the striatum part of our brain, and once we engage in the task, staying in that state uses less energy than multitasking and actually reduces the brain’s need for glucose.

Multitasking has been found to increase the production of the stress hormone cortisol as well as the fight-or-flight hormone adrenaline, which can overstimulate our brain and cause mental fog as opposed to clarity. Multitasking creates a dopamine addiction feedback loop, and the pre-frontal cortex is hijacked by new stimulations. Instead of reaping the big rewards that come from sustained focused effort, we get instead empty rewards for completing multiple low calories tasks. Just having the opportunity to multitask is detrimental to cognitive performance.

Therefore, if it appears that we are able to perform several things at once, multitasking is a powerful illusion. Farl Miller, a neuroscientist at MIT and one of the world experts on divided attention, says that our brains are not wired to multitask well. When people think they are multitasking, they are actually switching from one task to another one very rapidly. Every time they do, there is a cognitive and an energy cost in doing so. Even though we think we are getting a lot done, ironically, multitasking makes us demonstrably less efficient.

Research on Performance

The growth and expansion of communication technology have created a multitasking generation among people, millennial and students who believe they are utilizing time more effectively by performing two or more tasks simultaneously. However, research by neuroscientists shows that multitasking reduces the brain’s ability to effectively retrieve information and multitasking in class affects the grade performance of business students. 62 undergraduate business students enrolled in the first accounting principles course at a university in the Southeastern part of the United States. The students participated in a class lecture and afterwards were given a quiz covering the lecture content. One-half of the participants were allowed to multitask in the form of texting during a class lecture, while the other half of the participants were not. The exam scores of students who text in class were significantly lower than the exam scores of students who do not text in class. Thus, multitasking during class can be considered a distraction that may likely result in lower grade performance. The implications of this study can be very useful to students, instructors, administrators, and other academic stakeholders, about the effect of multitasking in a learning environment on students’ grade performance.

When working on several tasks at once, such as talking on the phone, checking your email and writing a report, you can lose the focus required to adequately complete one item. Too many distractions break your concentration, which requires more time to come back to one task, find where you left off, and try to recreate your thought pattern. In their book, “The Complete Idiot’s Guide to Mindfulness,” Anne Ihnen and Carolyn Flynn discuss the bad effect of multitasking that does not allow your brain to rest between tasks, which wastes time in refocusing on the most important duty that must be performed.

Memory Impairment

Multitasking can lead to over-stimulation of your brain function. If you are working on a project or assignment and you are constantly interrupted by coworkers, phone calls, or customers, you risk forgetting details required to comprehensively finish the task. By having too much information inundate you at the same time, your brain cannot differentiate between what is important and what isn’t, negatively affecting your memory. A 2009 study by Clifford Nass, Ph.D., and others at Stanford University shows that participants who multitask the most are distracted by unimportant information that is stored in their short-term memory.

But what if some people have a special gift for multitasking? The Stanford researchers compared groups of people based on their tendency to multitask and their belief that it helps their performance. They found that heavy multi-taskers—those who multitask a lot and feel that it boosts their performance—were actually worse at multitasking than those who like to do a single thing at a time. The frequent multi-taskers performed worse because they had more trouble organizing their thoughts and filtering out irrelevant information, and they were slower at switching from one task to another.

Doing more than one task at a time, especially more than one complex task takes a toll on productivity. Although that shouldn’t surprise anyone who has talked on the phone while checking E-mail or talked on a cell phone while driving, the extent of the problem might come as a shock. Psychologists who study what happens to cognition (mental processes) when people try to perform more than one task at a time have found that the mind and brain were not designed for heavy-duty multitasking. Psychologists tend to liken the job of air-traffic control, noting that in these operations, as in others, mental overload can result in catastrophe.

Multitasking and Ageing

Studies have shown recently that older adults experience a more negative impact by distraction on performance assessment compared with younger adults, and an even greater impairment when multitasking. There is extensive literature indicating that older adults are highly susceptible to distraction and that this leads to impairment in performance. Research directed at understanding the basis of age-related interference effects is becoming increasingly important, as older adults remain engaged in the workforce later in life into a more demanding, high-interference environment.

Functional Magnetic Resonance Imaging (fMRI) has been used to elucidate the neural mechanisms that underlie the greater impact of interruption on performance in older compared with younger adults. To accomplish this, the same fMRI experiment that was used to assess cerebral process interference in younger adults was performed in older adults.  Older participants performed an identical experiment using fMRI recordings to that recently performed in younger individuals. A comparison of the behavioral datasets between age groups revealed that cerebral performance was more disrupted by interruption/multitasking in older adults than it was in younger adults, replicating previous findings obtained using a similar task and EEG recordings. Given the fundamental role of cerebral processing in higher cognition, this deficit may have an impact on a wide range of life activities. This result contributes to a growing literature documenting the consequences of multitasking on cognitive performance in older adults.

Research Significance

Although switch costs may be relatively small, sometimes just a few tenths of a second per switch, they can add up to large amounts when people switch repeatedly back and forth between tasks. Thus, multitasking may seem efficient on the surface but may actually take more time in the end and involve more error. Understanding the hidden costs of multitasking may help people to choose strategies that boost their efficiency – above all, by avoiding multitasking, especially with complex tasks. (Throwing in a load of laundry while talking to a friend will probably work out all right.) For example, losing just a half-second of time to task switching can make a life-or-death difference for a driver on a cell phone traveling at 50 MPH. During the time the driver is not totally focused on driving the car, it can travel far enough to crash into an obstacle that might otherwise have been avoided. Meyer and his colleagues hope that insights and understanding switching costs may help to improve the design and engineering of equipment and human-computer interfaces for vehicle and aircraft operation, air traffic control, and many other activities using sophisticated technologies.

Potential Harm from Multitasking

The proliferation of smartphones has brought us to an era of unprecedented connectivity. Consumers around the globe are now constantly connected to faraway friends, endless entertainment, and virtually unlimited information. With smartphones in hand, they check the weather from bed, trade stocks—and gossip—while stuck in traffic, browse potential romantic partners between appointments, make online purchases while standing in-store, and live-stream each others’ experiences, in real-time, from opposite sides of the globe. Just a decade ago, this state of constant connection would have been inconceivable; today, it is seemingly indispensable. Smartphone owners interact with their phones an average of 85 times a day, including immediately upon waking up, just before going to sleep, and even in the middle of the night

While often being reminded to pay full attention while driving an automobile, people regularly engage in a wide variety of multitasking activities when they are behind the wheel. Indeed, drivers are spending more time on the road, commuting, travelling, or for pleasure. Engaging in these multitasking activities often comes at a cost of diverting attention away from the primary task of driving. The cell phone conversation causes a withdrawal of attention from the visual scene, yielding a form of inattention blindness. One study found that having an accident is four times more likely when using a cell phone while driving. Another study compared reaction times for experienced drivers during a number of tasks and found that the subjects reacted more slowly to brake lights and stop signs during phone conversations than during other simultaneous tasks. A 2006 study showed that drivers talking on cell phones were more involved in rear-end collisions and sped up slower than intoxicated drivers. When talking, people must withdraw their attention from the road in order to formulate responses. Because the brain cannot focus on two sources of input at one time, driving and listening or talking, constantly changing input provided by cell phones distracts the brain and increases the likelihood of accidents

In a study by Mazzae et al, 2004, comparing hand-held and hands-free cell phones showed that the impairments to driving are identical for these two modes of communication. There was no evidence that hands-free cell phones were any safer to use while driving than hand-held devices as significant interference was found. Although there is good evidence that manual manipulation of equipment (e.g. dialing the phone, answering the phone, and so forth) has a negative impact on driving, the distracting effects of cell phone conversation persist even when these manual sources are removed. Moreover, the duration of a typical phone conversation is often significantly greater than the time required to dial or answer the phone. Thus, these data call into question driving regulations that prohibit hand-held cell phones and permit hands- free devices, because little difference was found in the impairments caused by these two modes of cellular communication.  An important epidemiological study by Redelmeier and Tibshirani (1997) found that cell phone use was associated with a fourfold increase in the likelihood of getting into an accident, and that this increased risk was comparable with that observed when driving with a blood-alcohol level at the legal limit. The simulator-based research controlling for time on task and driving conditions found that driving performance was more impaired when drivers were conversing on a cell phone than when these same drivers were intoxicated at 0.08 wt/vol. Taken together, these observations provide clear-cut evidence indicating that driving while conversing on either a hand-held or hands-free cell phone poses significant risks both to the driver and to the general public.


Studies, literature, articles and worldwide universities and workplace, stress the fact that multitasking of any kind reduces the productivity and/or increases the rate of errors, thus generating unnecessary frustrations. Because the brain cannot fully focus when multitasking, people take longer to complete tasks and are predisposed to error. When people attempt to complete many tasks at one time, “or [alternate] rapidly between them, errors go up, and it takes longer to get the jobs done. This is largely because “the brain is compelled to restart and refocus. Therefore, multitasking people not only perform each task less suitably but lose time in the process.

It is difficult, if not impossible, to learn new information while engaging in multitasking. Multitasking affects academic performance and students who engaged in high levels of multitasking reported significant issues with their academic work. Using Facebook and text messaging while studying, negatively impact on student grades. There is also a great deal of evidence showing the negative effects of multitasking on cognitive tasks, on creativity, on performance at any level, but there is little evidence showing that multitasking has a positive effect. What’s about multitasking while driving with its potentially devastating consequences?

The lesson? Multitasking is not a skill to add to the resume, but rather a bad habit to put a stop to. The power of multitasking is a myth that has not help anybody to efficiently accomplish multiple tasks.



References and Further Reading

1. Omar Al-Hashimi, Theodore P. Zanto and Adam Gazzaley. Neural sources of performance decline during continuous multitasking.,  (2015), Cortex, 71.
2. Kiesel A., Steinhauser M., Wendt, M., Falkenstein, M., & Jost, K., Control and Interference in Task Switching. A Review. (2010),136.
3.Wesley C. Clapp, Michael T. Rubens, Jasdeep Sabharwal, and Adam Gazzaley. Deficit in switching between functional brain networks underlies the impact of multitasking on working memory in older adults. PNAS | April 26, (2011), | vol. 108 | no. 17.
4. Eyal Ophira, Clifford Nassb, and Anthony D. Wagner. Cognitive control in media multitaskers.  (2009), PNAS, Early Edition 1.
5. David L. Strayer and Frank A. Drews. Multitasking in the Automobile. (2006), Chapter 9, Kramer.
6. Adrian F. Ward, Kristen Duke, Ayelet Gneezy, and Maarten W. Bos. Brain Drain: The Mere Presence of One’s Own Smartphone Reduces Available Cognitive Capacity, (2017), JACR, Published online April 3, volume 2, number 2.
7. Gopher, D., Armony, L. & Greenspan, Y. Switching tasks and attention policies. (200), Journal of Experimental Psychology, General, 129, 308-229.
8. Mayr, U. & Kliegl, R. Task-set switching and long-term memory retrieval.  (2000), Journal of Experimental Psychology: Learning, Memory, and Cognition, 26, 1124-1140.
9. Meuter, R. F. I. & Allport, Bilingual language switching in naming: Asymmetrical costs of language selection. (1999), A. Journal of Memory and Language, 40(1), 25-40.
10. Meyer, D. E. and Kieras, D. E. A computational theory of executive cognitive processes and multiple-task performance: Part 1. Basic mechanisms. (1997), Psychological Review, 104, 3-65.
11. Meyer, D. E. and Kieras, D. E. A computational theory of executive cognitive processes and multiple-task performance: Part 2. Accounts of psychological refractory-period phenomena. (1997), Psychological Review,104, 749-791.
12. Monsell, S., Azuma, R., Eimer, M., Le Pelley, M., and Strafford, S., Does a prepared task switch require an extra (control) process between stimulus onset and response selection? (July 1998), Poster presented at the 18th International Symposium on Attention and Performance, Windsor Great Park, United Kingdom.
13. Monsell, S., Yeung, N., and Azuma, R. Reconfiguration of task-set: Is it easier to switch to the weaker task?  (2000), Psychological Research, 63, 250-264.
14. Monsell, S. and Driver, J., Control of cognitive processes: Attention and Performance. Eds. (2000), XVIII.Cambridge, Mass.: MIT Press.
15. Rogers, R. and Monsell, S. The costs of a predictable switch between simple cognitive tasks. (1995), Journal of Experimental Psychology, 124,207-231.
16. Rubinstein, J., Evans, J. and Meyer, D. E. Task switching in patients with prefrontal cortex damage. (March 1994), Poster presented at the meeting of the Cognitive Neuroscience Society, San Francisco, CA, Abstract published in Journal of Cognitive Neuroscience, (1994), Vol. 6.
17. Rubinstein, J. S., Meyer, D. E. and Evans, J. E. Executive Control of Cognitive Processes in Task Switching. (2001), Journal of Experimental Psychology: Human Perception and Performance, 27, 763-797.
18. Yeung, N. and Monsell, S. Switching between tasks of unequal familiarity: The role of stimulus-attribute and response-set selection.(2003), Journal of Experimental Psychology-Human Perception and Performance, 29(2): 455-469.
19. Strayer, David L.; Drews, Frank A.; Crouch, Dennis J. “A Comparison of the Cell Phone Driver and the Drunk Driver”. (2006). Human Factors: The Journal of the Human Factors and Ergonomics Society. 48(2): 381–391.
20. Klingberg, Torkel,  The Overflowing Brain: Information Overload and the Limits of Working Memory. (2009), Oxford: Oxford UP. pp. 7, 8.
21. Foehr U., Media Multitasking among American Youth. (December 2006). The Henry J. Kaiser Family Foundation. Kaiser Family Foundation. Retrieved 3-8-2010.