Multitasking Debate

Multitasking used to be viewed in a positive light. The image of the worker who could juggle five projects at once while responding to phone calls at the same time was once the picture-perfect worker in the modern office. Starting in the late 20th century, however, psychologists started to carry out research focusing on the effects of multitasking on the brain. Fast forward to today, and multitasking is no longer viewed in such a positive light. Many articles on the internet now claim that multitasking is actually bad for your brain. I was understandably worried by this claim and decided to look through the latest science myself. This is what I found.

Some studies have found that heavy multitasking decreases working memory. To understand this conclusion better we should first understand the methodology of the studies. The studies split their participants into two categories, HMMs (heavy media multitaskers — people who multitask a lot) and LMMs (light media multitaskers — people who don’t multitask much).

They had the HMMs and the LMMs perform a WM (working memory) task. The task was to memorize two, four, six, and eight objects and repeat them back after some period of time. There was no significant performance difference between the HMM and LMM groups when scores were aggregated across the two, four, six, and eight object trials. However, when only the two-object trial was considered, the HMM group did significantly worse than the LMM group. This suggests that multitasking may have a negative effect on WM for easier tasks.

Similar studies were done for other WM tasks. Instead of just memorizing objects and repeating them back, participants had to do things like solve math problems in between memorization and recall. The study results were mixed: some studies found that the HMM group did worse than the LMM group, other studies noticed no change.

Overall, the evidence is unclear. Some studies found no WM effect from multitasking, while others found a negative effect. Importantly, no studies found a positive effect. Therefore, while multitasking might not be bad for your WM, it definitely doesn’t improve it. And as some people posit a link between intelligence and WM, there’s a chance that multitasking, indeed, does make you slightly dumber.

Some studies have also found that HMMs are less able to sustain attention over long periods of time. One study had participants respond to predictable metronome tones over 20 minutes. HMMs performed worse than LMMs. In another study, participants were shown a series of targets, and were asked to point out when infrequent targets appeared. HMMs also performed worse on this task. Once controlled for age, however, the results were no longer significant.

More complicated studies about attention have also been done. They have mixed results — some finding no correlation between HMM/LMM and attention ability, some finding HMMs are worse. Again, no studies showed positive correlation between HMMs and attention ability.

We would except HMMs to be more efficient at task switching than LMMs. In reality studies paint an unclear picture. One study of this subject had the participants classify number-letter pairs based on either the number or the letter.

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