Why is it harder to remember things when you’re multitasking?

Moving between data analysis, mails and meetings often feels like efficient problem solving. However, from a neurobiological perspective, multitasking forces the brain into a sort of contextual shift that is taxing on both your energy and precision. 

Short term memory can only handle a limited number of units of information at a time, typically 4–7. Every time you switch tasks, the prefrontal cortex has to temporarily deactivate one representation and activate a new one.

This takes time, and during this interval what research calls attention residue occurs: the remains of the previous tasks that still occupy neural resources.

As a result, learning, problem-solving and decision-making become less efficient.

The hippocampus, which consolidates information from short-term to long-term memory, doesn’t get enough rest to stabilise the synaptic connections which are responsible for lasting knowledge.

The cost of frequent changes

Experiments from both Stanford and University of Sussex show that chronic multitaskers actually display a reduced memory and a lowered grey matter volume in the anterior cingulate cortex – an area that controls focus and emotional regulation.

Therefore, it is not only efficiency that declines; the structure of the brain conforms to the habit of fragmented attention.

At the same time, activity rises in the amygdala when we get interrupted, which activates a stress response.

This means that the brain practically functions in a constant state of alarm, where cortisol levels rise and the ability to reach deep concentration is further reduced.

Sequential thinking – the original design of the brain

The human brain has evolved to process information sequentially: one task at a time with the ability to integrate information over time.

When we respect this structure – e.g. by grouping together similar tasks and minimizing context change – we prolong both precision and cognitive stamina.

A study from University of California showed that participants who worked undisturbed for 45 minutes had 50% fewer errors and remembered twice the amount of the task’s contents compared to those who were interrupted every 15 minutes.

When task switching is unavoidable

Even the most well-structured workday can bring interruptions, urgent tasks and last-minute changes.

Research into cognitive flexibility shows that you can reduce the effects of attention residue by helping your brain ‘close’ a thought before opening the next:

1. Have a 20–30 second micro break.
   Brief quiet or deep breathing lowers the activity in the amygdala and helps your brain reset the neural pattern from the previous task.
2. Wrap up consciously – not abruptly.
   Write down a sentence about where you left the task: ‘Next step: analyse dataset B.’ This helps the hippocampus by marking a natural end to the task and frees up your working memory.
3. Give your brain an anchor when switching contexts.
   Use small rituals – e.g. by physically moving, changing displays or closing a notebook – so your brain gets a clear signal that you’re starting a new task.
4. Take longer breaks after frequent task switches.
   If you’ve had a day with many short tasks, your brain needs a longer period of uninterrupted time afterwards to restore dopamine balance and rebuild mental energy.

Small and deliberate transitions reduce the mental backlog and makes it easier to maintain both focus and precision – also when everyday life requires flexibility.