Research Suggests Brain Has a 2-Task Limit for Multitasking

suraj.sun writes with a story from LiveScience about just how much attention you can devote to each of the tasks on hand that scream for it: "The brain is set up to manage two tasks, but not more, a new study suggests. 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 Université Pierre et Marie Curie in Paris, France. 'However, we cannot multitask with more than two tasks.'"

Comments

what is a single task to the brain?

[slashmojo]

Is talking on the phone really a single task? Is cooking? Surely each of those is made up of countless sub-tasks even if you don't consciously think about them.

Re:what is a single task to the brain?

[Pharmboy]

Is talking on the phone really a single task? Is cooking? Surely each of those is made up of countless sub-tasks even if you don't consciously think about them.

If you were just saying random words, then perhaps not. But if you are discussing the new project at work, or what little Johnny did at school, or even about sports, it requires pulling in previous experiences, remembering specific events, drawing conclusions, etc., which are "subroutines" in a single task, communicating. A phone conversation can actually take more brain power than driving down the highway. Think about it, when someone is driving and talking on the phone, it is obvious that the cell phone requires more attention than driving. As for being sub-tasks, all tasks are generally linear subtasks that would qualify as a single task.

Perhaps that is why people tend to stray into the other lane when driving/talking on the cell. A third activity comes in or they have to fork a thought for consideration during the conversation, and they run out of brainpower/memory, so the least important activity (driving) gets swapped out for a second. Humans just need more RAM.

How about that, a computer analog for a car problem, instead of the other way around!

Re:what is a single task to the brain?

[UpnAtom]

Especially in men, right brains don't talk. So that's exclusively left-brain.

Driving (at least the direction & speed control) is right brain. The time it's most likely to engage your left brain is when you have to consciously think ie planning your route, adapting to unusual road conditions. Apart from that driving & talking is fairly easy for experienced drivers. Typically, drivers talk in a monotonous voice as inflection is right hemisphere.

Try adding a column of figures eg restaurant bill and having a conversation at the same time - pretty damn hard because both are left brain. So there we're only single-tasking.

I think what this research shows is that we use both sides of our brain when we're single-tasking. Some areas of the brain are very specialised but other areas can be trained to perform similar functions (for some people, the right hemisphere spelling a word would be an unnatural task). If we're doing two tasks for which different hemispheres of the brain can assigned one of the tasks, then the brain is quite adept at dividing up the workload.

Re:what is a single task to the brain?

[Theril]

I don't think that the hemisphere-function division is as straightforward as you, and much of popularized psychology, suggest. From eg. lesion studies the evidence seems to hint that there are some tendencies to somewhat specialized functionality in the hemispheres, but these are quite "vague".

Some quotes from Wikipedia to back this up:

"Broad generalizations are often made in popular psychology about certain function (eg. logic, creativity) being lateralised, that is, located in the right or left side of the brain. These ideas need to be treated carefully because the popular lateralizations are often distributed across both sides."

"Hines (1987) states that the research on brain lateralization is valid as a research program, though commercial promoters have applied it to promote subjects and products far outside the implications of the research. For example, the implications of the research have no bearing on psychological interventions such as EMDR and neurolinguistic programming (Drenth 2003:53), brain training equipment, or management training."

http://en.wikipedia.org/wiki/Lateralization_of_brain_function

Also the study that the article refers to does some quite bold assumptions about how brain works (eg. quite strict functional localization) and the whole concept of "task" is so generally defined that it's quite easy to escape any falsification by modifying its properties.

In general, most of the stuff about psychology/cognitive science that "leaks" to public should be taken with a grain of salt. Much less about brain functioning is known that may appear to a casual reader, or to some self-criticism challenged researchers.

Please define task

[houghi]

I can eat, breath, type and read at the same time while listening to music.
At these moments I am also thinking ahead of what I am going to do.

Even typing could be considered doing several tasks at the same time. The sample of 'cooking' in the summery can be defined as multiple tasks. You are standing, you are tasting and smelling, you are planning of what to do next and probably stirring as well as looking.

For a chef in a kitchen, cooking is also interacting with other people at the same time.
For some people cooking is pressing the button on the microwave and waiting for the 'ting' of the machine.

So what is a 'task'?

Re:Women can do it better..

[Rogerborg]

Based on this research, it would appear that women are better at cooking and talking on the phone. Gasps of surprise, and film at 11, probably something with Renee Zellweger being charmingly quirky.

Re:I used to work on the road...

[lattyware]

Not having an accident doesn't make it safe.

Pick two

[characterZer0]

Thinking
Talking
Listening

Pick two.

Re:Pick two

[IANAAC]

If you are an interpreter, you routinely do all three at the same time.

Sorry, just because it's difficult for some doesn't mean it's impossible. It does take training and practice, though.

A victory for the workforce

[sanche]

I'm glad to see this. There are way too many people in my business life claiming to be good at multitasking when their only real strength is never giving anything their full attention.

It takes a certain amount of horsepower for your brain to help you get through a list of tasks, simple or not. When you focus, you get those things done faster, and usually at a higher quality.

Practice

[TheLink]

Seriously though, you might be able to learn how to do that if you could practice doing that 100 times every day, for a month under safe simulated conditions (e.g. driving simulator, and simulated eating too, otherwise you'd end up killing yourself by overeating ;) ).

It's all about practice. Practice, practice, practice.

The first time you drive a car (especially a manual), there are so many tasks.

After a while of practice, your brain configures itself to automatically make those tasks into a subtask, and groups them all into one task - "driving".

Of course some people may never be able to do it. But I think a high proportion of people can. And I bet there are some people who can learn to do it after very short time - just like some people can learn to juggle very quickly, and there was that recent article about supertaskers.

I'm sure Michael Schumacher can eat breakfast and type on a cellphone and still do F1 laps faster than I can, when I'm just doing F1 laps (just driving, not eating or doing other stuff).

The trouble with most people is they're trying to do "for real" without practicing _properly_. That's like trying to juggle chainsaws, without learning how to juggle balls first, and then gradually working your way up under controlled conditions.

Re:Practice

[TheLink]

1) You don't need full situational awareness[1] while driving to be safer than the average driver. If we ever are going to officially allow some drivers to multitask, there better be a driving test where people have to prove that they are much better than the average driver while multitasking. Then we ( the average drivers) are far more likely to kill them than the other way round ;). I'd prefer it if every driver was required to take that test, even if they can't pass it (and don't have to for a normal license) - it's a good thing to try to make most of us know how crappy we are at driving.

2) Don't do multiple dangerous tasks at once. That way you can drop the other tasks if "stuff happens". The trouble is even with a hands-free kit, too many people are too stupid[2] to just shut-up and drive when stuff gets dangerous.

[1] There are zillions of things a driver can be aware of which can improve safety, but we don't require all of them to drive better than average. The average driver does not look for toddler/animal feet under parked cars, and prepare to brake. So many drivers don't even seem to look many cars ahead for potential issues (prepare to change lanes well before the problem). And you can easily learn to do this sort of stuff even if you are talking to someone else (if you can't multitask, just stop talking, do stuff, resume talking).

[2] I saw a video where a sword swallower said he had a bad accident when a bird sat on his shoulder unexpectedly. To me that shows he is very bad at prioritization for him to do what he does safely. When you have a sword swallowed in your throat, you do NOT turn your head no matter what. It's like the "pain box" test in Dune.

The type of task matters

[Webz]

In my opinion, the type of task matters. And I think it has to do with what parts of your brain are used. For example, I can code/refactor and listen to a podcast just fine simultaneously. But if it's two comprehension-based tasks, like reading AND listening, I can't do them. Or lately I've even noticed I can't mentally elaborate on a thought and listen to a podcast at the same time.

The coding and listening thing seems very left brain/right brain to me.

Also, to the poster that mentioned musical multi-tasking... That's really interesting! But I think it helps that we as musicians have been training since a very young age to accept that level of multi-tasking, so the things that become muscle memory do. Fingering, breathing, sight reading, etc. Really the only thing that matters by show time is watching the conductor, the rest should be on semi auto pilot.

Re:OMG! Is that BASIC I see???

[mswhippingboy]

Typical iPhad response. 3 sequential steps and call it multitasking :)
Oh wait, I forgot, iPhad can only multitask 2 tasks (one builtin app and one 3rd Party app). No, background notifications don't count. If interrupt handling is considered multitasking, then msdos was a multitasking beast (I wrote many TSR apps back in the day).
Full disclosure: I'm writing this on my iPhad so don't peg me as anti-apple (I have 4 more iPhads I'm paying for for wife&kids). I'm supporting Apple more than any shill so I will speak my mind.
The last time I made a remark critical of apple I got modded troll so I'm aware of the iGod followers here.
If this draws a troll mod, then I say F U moderator.

Re:Musicians

[phantomfive]

Reading the study (actually the summary), I think the problem is the people doing the test weren't actually switching tasks, they were trying to focus on all the things at the same time. I notice that when I work on multiple things (for example, music), I am actually switching between them very quickly. As an example, playing the piano and singing, it's like I queue up a line of words in my mind to sing, then switch instantly back to whatever my fingers need to do. You just get very good at switching between things. Which is actually multi-tasking, even as the scientist in the story uses the word.

The people in the story didn't seem to be switching. They were presented with moderately uncommon tasks, and from the MRI it appears they didn't actually switch, they were keeping everything in their mind the whole time, It is well known that you can only keep seven things or so in your mind at the same time, so this is not surprising. If they hadn't used the MRI then this story would have been utterly uninteresting, but even as it is, I don't think the facts of the study supports the author's conclusions.

PS To avoid a headache have you tried giving more sugar to your brain? Bobby Fischer used to drink fruit juice during chess games to help keep up his concentration.