The Cognitive Costs of Multitasking

This blog post is inspired by the Chapter 5 of the book "Present!" by Tita Grace Chong. The chapter is about good multitasking vs. bad multitasking. Tita Grace talked about how multitasking succeeded in dominating the millenials. Tita Grace stated that multitasking while driving is very dangerous because this can lead to vehicular accidents. So I tried searching for the neural basis of multitasking. What happens to our brain when we multitask? And how does it affect our health? Please take time to read this post. It's a bit lengthy but I hope you will learn a lot from it.

Also, if you still don't have your copy of the book "Present!" you can buy it from OMF Literature Bookstores. Happy reading everyone!

Neural Basis of Multitasking

Are you interested to know the science behind multitasking? What happens in our brain when we switch from task to task? Is multitasking beneficial and healthy for our brain? I hope I can answer some of these questions in this blog post.

Recent studies have shown the neural basis of multitasking. This can be the reason why some people are better at switching between different tasks and why some people suck at multitasking. Researchers from University of Pennsylvania, Germany's Central Institute of Mental Health and Charite Univesity Medicine Berline have studied the mechanisms behind cognitive flexibility using brain scans to elucidate the science of multitasking [1].

They studied the connections and networks of activity in the brain's frontal cortex. The frontal cortex is associated with emotion, reward, attention, short-term memory task, long-term memories which are not task based, planning and motivation. Researchers have shown that the degree of reconfiguration of the networks in frontal cortex when switching from task to task predicts people's cognitive flexibility. This means that people who have the most rearrangement of connections within their frontal cortices as well those who have the most new connection with other areas in their brain can perform best in switching tasks or multitasking [1].

These information regarding the dynamic reconfiguration of networks in human brain can be used to advance human understanding of disorders with prominent cognitive disturbances like autism and schizophrenia and dementia. Also it will be interesting to know the how multitasking can affect the millenials in this digital/electronic age. Although there are several benefits from multitasking, we cannot hide the fact that this can also cause distraction in learning and performance of a person. It is interesting to know how the educational systems should adapt to the multitasking and electronic "now generation". 

Effects of Multitasking in Human Health

People think they are multitasking. But actually they're not. They are just switching from one task to the other. And there are cognitive costs every time people do rapid shifting of tasks. Here are some reasons why multitasking can make us less efficient.

1. Decreased Brain Activity. Decreased Performance.

One of the common situations of multitasking is the use of a mobile phone during other activities such as driving. Many studies have shown that driving performance is decreased by a simultaneous phone conversation. One study observed the brains of people driving while listening to a conversation partner. The participants used a driving simulator to steer a car along a winding road and their brain is scanned in an MRI scanner. The study observed a decrease in brain activation from single to dual tasking approximately 37% in the brain areas involved in driving task. This lowering in the brain activation due to multitasking was accompanied by a poor performance in driving. The results of this study can also be applied to the use of hands-free mobile phone while driving. And since this study points that listening to sentences degrades driving performance, other common driver activities such as listening to a radio, eating, drinking, monitoring children or pets or even conversation with a passenger can cause such degradation [2].

2. Multitasking Splits the Brain

Another study concluded that the brain cannot efficiently juggle more than two tasks because it only has two hemispheres available to manage and process the tasks. Working on a single task activates both sides of the brain while dual-tasking causes the brain to split in activity. One task is processed in the left side of the frontal cortex while the other task on the right side. Each side of the brain worked independently. This study also observed that as you increase the number of tasks done simultaneously, many errors are committed and other tasks are easily forgotten. Technically you can do two tasks at the same time but adding a third task will cause your brain to discard one of the three tasks because the brain can only efficiently process two tasks simultaneously [3].

3. Production of Stress Hormones

Multitaskers have higher levels of stress hormones compared to their single-minded counterparts. Stress hormones are released in times of fear by the adrenal glands as part of the human fight-or-flight mechanism. These stress hormones like cortisol can damage the brain cells over time. This stress hormone can result to foggy short-term memory, difficulty concentration or gaps in attentiveness [4]. Other health effects of increased cortisol production are anxiety, depression, digestive problems, heart disease, sleep problems, weight gain, memory and concentration impairment [5].

4. Lose Focus and Attention

Multitasking stimulated the dopamine-addiction feedback loop. This mechanism effectively rewards the brain for losing focus and for constantly searching for external stimulation. The prefrontal cortex has a novelty bias. This means that the brain is easily hijacked by something new. It is so ironic that the part of our brain which is involved in focusing and staying on task is easily distracted. [6]. Dopamine is a hormone that lets you feel enjoyment and pleasure. It causes you to want, desire, seek out and search. It makes you curious about things and ideas thus stimulates you to search for more information. Your brain gets reward from dopamine every time you seek for more information. It then becomes harder and harder to stop seeking for more. This is the main reason why it's so hard to stop looking at email, stop texting or stop checking you mobile phone to check if someone messaged you or called you [7].

5. Information Goes to the Wrong Part of the Brain

A neuroscientist from Stanford University found out that learning information while multistaking can direct new information to wrong parts of the brain [6].

6. Depletion of Nutrients in the Brain

We now know that multitasking is actually task-switching. It is actually one of the most rapid ways to deplete brain energy. When performing a task, the prefrontal cortex recruits different networks of brain cells to carry out the task you want to accomplish. You use different brain networks to perform different kinds of tasks like texting, surfing the internet, personal conversation etc [6]. These task-switching has its metabolic cost. It causes the brain, specifically the prefrontal cortex, to burn up oxygenated glucose which is the source of energy and the fuel we need to stay on task. Rapid shifting from task to task during multitasking causes the brain to burn so much energy. This is the reason why we feel exhausted and disoriented after a short time of multitasking. We deplete our brains of nutrients and this leads to decrease in cognitive and physical performance [8].

Thank you for reading.

References

[1] Braun U et al. 2015. Dynamic reconfiguration of frontal brain networks during executive cognition in humans. Proceeding of the National Academy of Sciences. 112(37)

[2] Just MA and Buchweitz A. What brain imaging reveals about the nature of multitasking. Susan Chipman (Editor). The Oxford Handbook of Cognitive Science. New York: Oxford University Press

[3] http://news.sciencemag.org/2010/04/multitasking-splits-brain

[4] Hanna H. 2013. The Sharp Solution: A Brain-Based Approach for Optimal Performance. John Wiley & Sons

[5] http://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress/art-20046037

[6] http://www.theguardian.com/science/2015/jan/18/modern-world-bad-for-brain-daniel-j-levitin-organized-mind-information-overload

[7] https://www.psychologytoday.com/blog/brain-wise/201209/why-were-all-addicted-texts-twitter-and-google

[8] http://www.smashingmagazine.com/2014/10/maximize-your-creative-energy/