Working while watching the messenger, listening to a meeting while writing email, helping with homework while checking my phone. It felt like doing everything, and each evening the ledger showed nothing done properly. I went looking for why, and it wasn't just me.
Multitasking fails because attention goes to one place at a time, and every hop between tasks bills a switch cost. What looks simultaneous is rapid alternating, and each alternation spends time putting down one task and reloading the other's rules and context. Studies report this stretching total task time by double-digit percentages and multiplying errors. The phone is the most common second task, and the people who believe they multitask well tend to score worst.
Outside cases where one task runs on automatic, walking while talking, people cannot do two attention-demanding tasks at once. The feeling of simultaneity is rapid alternation between the two. And each alternation bills a fee: the time to set down the first task and reload the second's rules and context. This is the switch cost.
One switch costs little: seconds, sometimes tens of seconds. Hundreds of switches a day sum to hours. And time isn't the whole bill. Right after a switch, errors climb, and work that needs depth never starts at all.
| What was studied | Direction of results |
|---|---|
| Alternating two tasks | Longer total time and more errors than one at a time |
| More complex tasks | Larger switch costs |
| Habitual multitaskers | Weaker at filtering irrelevant information |
| The self-rated skilled | Actual scores tend lower |
| Laptops and phones in lectures | Comprehension drops, for the user and the neighbor |
The phone is always in hand, wakes in one second, and supplies second tasks without limit: messages, feeds, videos, news. Whatever you're doing, a phone beside it makes the doing multitask. We call the mid-work glance a little break, but to the head it's a switch, work to phone and back. I counted my daily switches once: past a hundred. Each one was a moment, and the evening held nothing done deep.
Across several studies, people who rated themselves skilled multitaskers scored lower on filtering out irrelevant input. The arrow seems to run backward: not skilled therefore frequent, but frequent therefore feeling skilled. Get used to switching and the sensation of its difficulty dulls, and the dulling invites more switching. I counted myself pretty good too. Until I counted.
Methods and samples differ across studies, so exact figures vary. What's written here is where the directions agree.
Sumbi's dive removes the phone from the second-task seat. For the set time, your remaining breath shrinks only while another app is open, and a dark screen never fails you. Whatever you do in that window becomes a single task. The simplest way to erase a switch cost is to remove the thing you'd switch to.
Dive for your study session →Trying not to multitask is harder than deleting the second task. Working: phone in another room, messenger closed, one browser tab. With no second task in the building, switching has nowhere to go.
Messages, email replies, and phone checks get set windows, three or four a day. Outside them, one thing. Cut the switches from a hundred to ten, and the bill drops with them.
This is something I learned as a parent: check my phone while helping with homework, and my kid knows, and so do I. Neither gets done. Thirty minutes fully beside my kid, phone away, left more behind than two distracted hours ever did.
One line from a phone-down day. The day after I counted my switches, I put the phone in another room and did one thing all morning. It finished before lunch. That task usually lasted until dinner.
This article is general information, not medical advice. If sleep or daily life stays disrupted, talk to a professional.
Sumbi