Don’t be too quick to feel proud if you believe you are capable of multitasking, or handling multiple tasks at once. Various studies suggest that this ability can actually reduce brain performance and even lower intelligence levels.

The human brain does not function like a computer that can run multiple programs simultaneously. Trying to do several tasks at once tends to decrease focus.

Research has found that frequent multitasking is associated with lower emotional intelligence. In fact, performing multitasking during cognitive tasks at work can reduce IQ by 10 to 15 points.

Moreover, the impact of multitasking is comparable to not getting enough sleep the night before, which ultimately decreases productivity.

The negative effects of multitasking are also discussed in the popular non-fiction book Ikigai: The Japanese Secret to A Long and Happy Life by Francesc Miralles and Hector Garcia.

The book explains that when people claim they can multitask, what they are actually doing is switching back and forth between tasks. Instead of completing work faster, this habit leads to a loss of focus.

In the human brain, multitasking is governed by executive functions, which manage cognitive processes and determine how, when, and in what order tasks are carried out.

According to researchers Meyer, Evans, and Rubinstein, executive control involves two stages. The first is “goal shifting,” which is the decision to switch from one task to another. The second is “role activation,” which involves adjusting from the rules of the previous task to those of the new one.

Switching between tasks may only add a few seconds to completing a task, but when done repeatedly, the cumulative time lost can become significantly greater.