Mentavo
The draft was nearly finished. Then a quick question came in on chat – two minutes, dealt with.
Back in the document the cursor sits exactly where it was, and the sentence that was clear a moment ago isn't any more.
The two minutes weren't the problem. The problem is that part of your attention is still with the question.
What actually happens when you switch
For most everyday situations, "multitasking" is the wrong word. What usually happens isn't simultaneity but rapid switching between tasks.
That switching is well studied. Alternating between two tasks makes each one take slightly longer and produces slightly more errors than working through one at a time. These switch costs show up reliably in laboratory experiments.
They are also small. We're talking about fractions of a second per switch – on their own, no explanation for a scattered working day.
The more relevant observation is a different one.
The remnant that stays behind
When you leave a task, it doesn't immediately leave your head. Part of your attention stays with it for a while – described in research as attention residue.
In practice that means the new task gets started at reduced capacity. Not because something has been used up, but because something is still occupied.
The effect is strongest when the task you left was unfinished, or was interrupted under time pressure. A completed thing is easier to let go of than an open one.
That fits a related observation: unfinished business stays more mentally accessible than finished business – which is the subject of the piece on why open tasks feel bigger in your head.
Why notifications weigh more than their duration
Reading a message takes seconds. The cost doesn't come from the reading.
It comes from the message opening a topic that was previously closed. A question without an answer, a task without a date, a disagreement without a resolution – all of it stays active afterwards, while the actual work is supposed to continue.
That's why the difference between "just a quick look" and not looking is larger than the duration suggests.
| Interruption | Duration | What stays open |
|---|---|---|
| Chat message with a question | under a minute | one unanswered question |
| Quick glance at the inbox | a minute | several half-started topics |
| Colleague asks about something settled | two minutes | little – the topic is closed |
The third row is the interesting case: a longer interruption can cost less than a shorter one, if it closes something rather than opening it.
Not every switch is a problem
This is a good place for restraint. The blanket claim that switching is harmful doesn't survive scrutiny.
What matters is what the tasks involved demand. Two activities that both require language, or both require deliberate decisions, interfere strongly. An automatic activity and a demanding one barely interfere at all – walking and thinking work fine; listening and writing don't.
Besides, many switches simply aren't optional. Anyone working in a team, living with children or handling customers can't opt out of interruptions. The question then isn't whether you switch, but what the way back looks like.
Why heavy switching feels productive
A day of many small completions often leaves the impression of having got a lot done.
The reason is that completions are countable. Fifteen answered messages make a visible tally; two hours on a difficult piece of writing make half a paragraph.
So the feeling measures the number of things finished, not their weight. The same confusion is covered in the piece on productive procrastination.
Why attention isn't a battery
A common explanation holds that attention is a limited supply that drains over the course of the day.
The image is intuitive and scientifically shakier than it looks. The idea of a depleting resource – known as ego depletion – has come under substantial criticism in recent years. Several large replication efforts failed to find the original effect at the expected strength.
The current view leans more towards expectations, motivation, interest and context mattering at least as much as any straightforward consumption. That concentration fades after hours isn't in dispute. That an empty tank is the reason for it is.
For everyday use: flagging attention isn't reliable evidence that you're "out of capacity" – it can just as easily point to monotony, a missing sense of purpose, or simply a short night. How much the shape of the day contributes is covered in the psychology of decision fatigue.
What makes the way back easier
Since interruptions can't be abolished, the workable approach sits at re-entry.
Leave the thread visible
Half a sentence describing what comes next saves you from reconstructing it on return. It costs a few seconds when you leave and considerably more when you come back.
Close what's open instead of memorising it
Whatever surfaces during an interruption and can't be dealt with immediately otherwise stays active. Writing it down – with a concrete when – tends to reduce its mental presence more than resolving to remember it. The piece on scattered notes makes a similar case.
Cluster switches rather than scattering them
Several interruptions in one block cost less than the same number spread across the day – not because of the time, but because of the number of returns.
What only shows up over weeks
Whether a scattered day was down to interruptions or to something else is hard to judge that evening. The impression leans heavily on how the day ended.
Recording briefly, over several weeks, how focused a day felt and what shaped it gives you something to compare later. In Mentavo, check-ins like that build up a run across longer stretches – it proves no connection, but it makes repetition visible.
How to separate real patterns from clusters is covered in pattern or coincidence.
What this article doesn't claim
Laboratory findings on switch costs don't translate directly into claims about lost working hours. Figures of that kind circulate, but they usually rest on heavy simplification.
Nor does this piece claim that single-tasking is always the better way to work. It is superior for some tasks and unnecessary for others.
And distractibility isn't a character defect. It depends heavily on the task, the environment and your state – a point also made in the piece on the attention crisis.
In short: the switch costs less than the return
The expensive part isn't the switch itself. It's what stays open behind you.
Taking that seriously means fighting interruptions less – and paying more attention to the state you leave a task in.
