Research
The idea behind Just Do Three isn't just intuition — research in psychology, neuroscience, and productivity consistently points in the same direction.
Psychology and neuroscience research shows that what we call multitasking is usually rapid switching between tasks, and those switches come with measurable cognitive costs.
When attention is constantly redirected, productivity slows, errors increase, and it becomes harder to finish meaningful work.
The studies and articles below explore the research behind these effects.
They're worth your time — add a few to your Just Do Three backlog and read them when you're ready!
Why Multitasking Slows Productivity
Sophie Leroy (2009) — Organizational Behavior and Human Decision Processes · sciencedirect.com
"Why is it so hard to do my work?" We love that quote at JD3! It really hits home.
When people switch from one task to another before finishing the first, part of their attention remains stuck on the previous task. This leftover attention—called attention residue—reduces performance on the next task and makes it harder to concentrate fully. The research shows how switching between tasks can slow progress and reduce effectiveness.
Wake Forest University · news.wfu.edu
Research on attention shows that every time the brain switches from one task to another it must disengage from the previous task and re-engage with the next one. These repeated transitions create delays and reduce efficiency, which is why multitasking often slows work rather than speeding it up.
American Psychological Association · apa.org
Research summarized by the APA shows that switching between tasks creates measurable delays as the brain disengages from one task and re-engages with another. These switching costs accumulate and can significantly reduce productivity.
The Case for Doing One Thing at a Time
Psychology Today · psychologytoday.com
Psychologists explain that multitasking is usually rapid attention switching rather than true parallel processing. When attention is focused on one task at a time, cognitive resources are used more efficiently, which improves both performance and quality of work.
mindspacex.com
Research on cognitive load shows that dividing attention across multiple tasks increases mental overhead and reduces efficiency. Focusing on one task allows the brain to process information more effectively and maintain deeper concentration.
Rubinstein, Meyer & Evans (2001) · apa.org
This one is really nerdy and we love it!
This widely cited study examined how the brain switches between tasks. The researchers found that shifting between tasks requires additional mental steps such as activating new rules and changing goals. These extra processes slow performance and create measurable switching costs, especially when tasks are complex.
Ophir, Nass & Wagner — Stanford University · pnas.org
Researchers compared heavy multitaskers with people who multitask less. The study found that heavy multitaskers performed worse on tests of attention, memory, and task switching. Instead of becoming better at managing multiple streams of information, they were more easily distracted and less able to filter irrelevant information.
Across many studies, the same pattern appears:
Just Do Three applies this insight in a simple rule.
Less switching. Less overwhelm. More progress.
