There is plenty of research showing that people can’t multitask. But this knowledge is missed by many people. Here is another study showing this: Why We Can’t Do 3 Things at Once

That’s because, when faced with two tasks, a part of the brain known as the medial prefrontal cortex (MFC) divides so that half of the region focuses on one task and the other half on the other task. This division of labor allows a person to keep track of two tasks pretty readily, but if you throw in a third, things get a bit muddled. “What really the results show is that we can readily divide tasking. We can cook, and at the same time talk on the phone, and switch back and forth between these two activities,” said study researcher Etienne Koechlin of the UniversitÃ© Pierre et Marie Curie in Paris, France. “However, we cannot multitask with more than two tasks.”

Now I wouldn’t base my judgement on this one study. But we don’t have to. Multitasking decreases productivity. The siren song of multitasking. Multi-tasking: why projects take so long. What we should strive for is flow, the opposite of multi-tasking.

The real world often requires dealing with many interruptions (forcing you not to multi-task but to break up your tasks into fragments). Single piece flow shows the value (the efficient system performance) of getting one thing done then picking up the next. Many interruptions force you to keep stopping and starting tasks. People think they are multi-tasking but in fact they are just doing 4 tasks serially switching back and forth between them. Which slows them down and increases the odds of forgetting something. In these environments checklists are even more important than if you are not being interrupted frequently.

Related: costs of context switching – The Multi-Tasking Myth – Interruptions Can Severely Damage Performance