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Modern humans are masters of multitasking. We eat while driving, watch TV while studying, and of course talk on our cell phones while doing, well, everything. How do we do it? A study in the July 16th issue of Neuron suggests that though we can train our brains to work faster as we juggle, we never actually manage to do more than one thing at a time.
Our brains aren’t really built to handle the sort of parallel processing we think we’re capable of. The good news is: studies have shown that extensive training can make us better at doing two things at once. But how?
One theory is that with lots of practice some routines become “automatic.” And if we don’t need to run every little thing past the part of the brain that’s spends time thinking about stuff, we can multitask just fine.
But this new study finds that that’s not the way it works. Turns out that multitaskers still consult the prefrontal cortex, but training gets the “Thinking Brain” to think a little faster. So we’re switching tasks quickly enough to appear to be doing them simultaneously. Which is still nothing to shake a stick and sneeze at.
—Karen Hopkin
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Add CommentI'm not sure I believe the conclusion, at least as stated here. Juggling, for example, is great example of an activity that is a "thinking" activity in this sense, meaning that if you stop paying attention for even a moment, balls tumble. Yet with training, juggling can become so seemingly automatic that it's possible to carry on an unrelated conversation, and even to let one's visual focus wander away from the balls (but close your eyes for even a brief moment, and everything falls apart immediately!). So from a subjective perspective at least, in my experience there is absolutely no experience of "switching" between the conversation and the juggling; they are simultaneous.
Reply | Report Abuse | Link to thisOf course, I concede it's possible that on the sub-conscious level, some internal processor is switching back and forth between these two tasks, too rapidly for the conscious mind to notice. But in the context of such a rapid-fire switching, why do I doubt that the Neuron study authors would be able to tease apart identifiable neurological processes associated with each separate task, in order to show conclusively that the prefrontal cortex isn't actually multitasking...?
I find myself doubting, as I chew my lunch.
In never ceases to amaze me when the most obvious is pointed out in a publication that considers itself a voice of science and, by association, clear thought.
Reply | Report Abuse | Link to thisI must admit, though, that my efforts to educate my acquaintances on this subject has also never ceased to be unproductive.
Ever since the term "multitasking" started to be applied to human activity, I've felt compelled to educate others by describing how humans engage in "time-division multiplexing", not "multitasking".
Worse, I've found every employer to throw the "multitasker" quality around quite thoughtlessly - and reward those seen as "effective multitaskers!" Continuing down the stupid ladder, it is also painfully apparent that those who are particularly "effective multitaskers" are so chaotic that their work is of chronically poor quality.
Is the gist of this article a surprise to any other readers?
I find that a bit hard to believe. If I'm chewing gum while driving, does that mean that I'm switching back and forth between the two tasks? If so, this switching is occurring so fast that you would have to say it practically is happening at the same time. I think much more research needs to go into this before I can buy it.
Reply | Report Abuse | Link to thisThe tasks that seem to become automatic with practice (juggling as was used as an example by Tucker) are part of motor memory and muscle memory, pattern generators if I remember correctly. These become almost a reflex as the frontal cortex is bypassed and the cerebellum and brain stem mediate the motor action. Perhaps this is a better explination as to why we can eat and read, etc. Different parts of the brain are active. However, reading and writing simultaneously... not as efficient.
Reply | Report Abuse | Link to thisThe tasks that seem to become automatic with practice (juggling as was used as an example by Tucker) are part of motor memory and muscle memory, pattern generators if I remember correctly. These become almost a reflex as the frontal cortex is bypassed and the cerebellum and brain stem mediate the motor action. Perhaps this is a better explination as to why we can eat and read, etc. Different parts of the brain are active. However, reading and writing simultaneously... not as efficient.
Reply | Report Abuse | Link to thisTucker M:
Reply | Report Abuse | Link to thisYou can personally 'believe' what you want, but the article was reporting measurements that were made. Is is a report. It is not to be confused with anecdotal pseudo-science that is so rampant in media today. Belief has nothing to do with scientific study.
P
You are reading this on a device using time-division multiplexing, even though you can not tell that the browser is not downloading the ad and displaying the page, the system showing the time, and Winamp downloading and playing music all at the same time. You glance at the kid catching the ball 10 feet from the street while talking and staying on the sidewalk. A good trick.
Reply | Report Abuse | Link to thisWhether it is multitasking or time-division muliplexing, I've noticed that women seem to be more able/comfortable doing multiple things at once than men. I'd be interested to see if there is any research that looks at this mental function comparing men and women's abilities.
Reply | Report Abuse | Link to thisDr Paul:
Reply | Report Abuse | Link to thisSo true. I just learned that someone can use their brain to shamelessly promote their web site while stating the perfectly obvious under the guise of an online comment. (It's called spam.)
To clarify a little this podcast:
Reply | Report Abuse | Link to thisJournal Neuron
Abstract
doi:10.1016/j.neuron.2009.06.005
Training Improves Multitasking Performance by Increasing the Speed of Information Processing in Human Prefrontal Cortex
Paul E. Dux1, 4, , , Michael N. Tombu1, Stephenie Harrison1, Baxter P. Rogers2, 3, Frank Tong1 and Ren� Marois1, ,
Accepted 2 June 2009. Published: July 15, 2009. Availableonline 15 July 2009.
Summary
Our ability to multitask is severely limited: task performance deteriorates when we attempt to undertake two or more tasks simultaneously. Remarkably, extensive training can greatly reduce such multitasking costs. While it is not known how training alters the brain to solve the multitasking problem, it likely involves the prefrontal cortex given this brain region's purported role in limiting multitasking performance. Here, we show that the reduction of multitasking interference with training is not achieved by diverting the flow of information processing away from the prefrontal cortex or by segregating prefrontal cells into independent task-specific neuronal ensembles, but rather by increasing the speed of information processing in this brain region, thereby allowing multiple tasks to be processed in rapid succession. These results not only reveal how training leads to efficient multitasking, they also provide a mechanistic account of multitasking limitations, namely the poor speed of information processing in human prefrontal cortex.
Nobody doubts we can walk and chew gum at the same time, but the common myth that we can "multitask" - do two conscious activities simultaneously - is hogwash and that assessment should be obvious to everyone. Some activities may be quite conscious when being learned, but transition to near-reflexive rote behaviors if conditions are suitably limited. Activities with limited conditions are of the "chewing gum" or "walking around the block", of course.
Reply | Report Abuse | Link to thisI see smarticus and lamorpa understand this just fine. Most people, though, do not. I'm afraid kjweber and Tucker M aren't too keen on distinguishing types of mental engagement. Sorry guys, it is what it is. Even more unfortunately, our esteemed author appears constrained by common myth as well by saying "training can make us better at doing two things at once" and then "we’re switching tasks quickly enough to appear to be doing them simultaneously" ... the question the study resolved was whether humans can do two things at once, and it shows we don't - we merely reduce the time period of the multiplexing and, I would dare say, reduce the depth of thought during the time we spend engaging the prefrontal cortex.
I agree that this seems plausible; further study will clear things up. However, the first example, eating while driving, is a poor one, isn't it? Does someone who is eating while driving stop driving when they take a bite? Is this report suggesting that s/he temporarily ceases the driving activity while taking a bite? Clearly not. I suppose the study suggests that the driver's concentration is shifted to the act of eating, but that fact alone does not exclude that s/he is "doing two things at once," because clearly s/he is.
Reply | Report Abuse | Link to this[q]I suppose the study suggests that the driver's concentration is shifted to the act of eating, but that fact alone does not exclude that s/he is "doing two things at once," because clearly s/he is.[/q]
Reply | Report Abuse | Link to thisI think you have a misconception of what is to do two things at the same time. At least it should be defined. Most of time people can take a brief pause from having an attention to driving for example to eat while in driving situation. But their attention actually is diverted for a moment and if something extraordinary happens while they are not paying attention to driving, that can cause dire consequences, like an accident. Eating at driving situation does usually only make short interruptions for driving attention, but for example talking on the (mobile) phone can make longer ones. And the longer we don't pay duly attention to traffic, the higher is the risk that something will be missed and that creates a risk of accident. People are here as many have stated like computers, doing time division multiplexing and when those time slots get long enough, that activity can and will disrupt one of those tasks. And the more tasks we are trying to do 'at once' the bigger is the risk of failing at it.
As Michael F just hinted at in the last post, do not forget that even though our body may be performing 2 separate actions (eating, driving, ...) our prefrontal cortex does not necessarily have to be processing those two things at the same time. Moreover, the study does not seem to exclude that the commands coming from the high level prefrontal processing are processed in later and simultaneously running stages by lower level control. The different low level controls for chewing and the ones for particular driving actions receive high level commands intermittendly, but may still be running continuously (and thus all at the same time) in order to complete these commands. As such our body will be responding continuously to the flow of motor commands from the low level controls. E.g. a short high level order to take a bite is followed by a 2-3 second action of our arm/hand to move the food to our mouth and to close it. During this action our prefrontal cortex can focus on driving.
Reply | Report Abuse | Link to thisBy the way, do not forget the tricky ways in which our minds keep telling ourselves that we are in full control of our actions (or multitasking actions for that matter). One interesting SciAm podcast about this is found here: http://www.scientificamerican.com/podcast/episode.cfm?id=93474982-0BBC-B7E8-34D917D42909AB06. Steven Pinker also has more about our idea of being in control in some of his books.
The same self deception is seen in the way we process visual information. Our eyes have only a small spot with high resolution and it gets maybe 90% of our brain's attention. Only in this small spot we see clearly, but by moving our eyes and thus our attention around it looks like we see everything perfect in high res at the same time, while in fact it is our attention quickly shifting back and forth.
I find it a ridiculous notion that multitasking ever became a thing of value. I can say from personal experience that the only thing multitasking between several tasks accomplishes is to cause each of those tasks to be performed at a subpar level. It's only because we live in this fast-paced business world that it's become an admirable trait. Too bad nobody has the time to notice.
Reply | Report Abuse | Link to thisNext research topic: The origin of pedantry, and why it seems to be so prevalent among blog talkback posters.
Reply | Report Abuse | Link to thisMulti-core systems notwithstanding. :)
Reply | Report Abuse | Link to thisPeople are getting this mixed up here because the article doesnt defined "task." As pointed out by smarticus, a trained reflex is not a task. There is a difference between what you are aware of doing and what you are actually doing. I clearly am not multi-tasking with every muscle I move to make a smile or wiggle each finger. This article and the scientists are referring to tasks which are mental not physical such as installing a program while watching TV.. reading a book while having a conversation.. etc. To make sure express myself better I must will note that we have different reflexes. A task, as it is learned, becomes reflex-like (less of a task)... and we are all different in the reflexes we have. We have trained to do various things in various ways. Driving and talking on the cell phone is time-division multiplexing but I am willing to bet that an experienced driver will have a more reflex-like perception for this type of multi-tasking than say a student driver.
Reply | Report Abuse | Link to thisJust a single thought.
Reply | Report Abuse | Link to thisIf in the process of taking the bite of the Big Mac, the oncoming car moves into your lane, all multiplexing ceases and true multitasking begins. Adrenaline dumps, hands turn wheel, foot hits brakes, and food flies from mouth.
I would have thought that a clear, everyday illustration of the multi-tasking myth would have been the research done on the use of mobile (cell) phones whilst driving. It has been demonstrated under controlled conditions that a driver is far more accident prone when talking on the phone as the level of concentration on either of the two tasks involved (driving or talking on the phone) is sufficient that one has to be made dominant at the expense of the other.
Reply | Report Abuse | Link to thisDriving and using a cell phone is a bit off topic, but I decided to ask the President and my Legislators to fix the problem. Feel free to do the same; here's an example of what I sent: http://docs.google.com/Doc?docid=0AVUeCUB9oIZZZGd6ZnZnZHFfNDFmczMyMmZkNw&hl=en.
Reply | Report Abuse | Link to thisAs to this podcast, SciAm seems to have an emphasis and conclusion that is different than the authors of the original article. See http://sitemason.vanderbilt.edu/news/releases/2009/07/15/multitasking-ability-can-be-improved-through-training.84357.
My students are convinced that they can multitask while "doing" math homework because they have trained themselves to do it all their lives. I would like to cite the podcast to convince them that they can't. But the original article supports their conclusion.
Conclusion from the 1st paragraph: "...we never actually manage to do more than one thing at a time. ..." does that "doing" exclude the funtions of breathing, perspiring, digesting food, etc. just because they are controlled by a different part of the brain? Is Karen Hopkin confining her discussion to multitasking of the processes through the
Reply | Report Abuse | Link to thisprefrontal cortex?
IS THIS A SUGGESTION OR A CONCLUSION? "... A study ... suggests... we never actually manage to do more than one thing at a time..." I would like to suggest that we define multi-tasking for the purpose of discussion. Shall we include the tasks of breathing, circulating blood, perspiring, digesting food, etc? I suggest that learned efficiency may be more like thinking/speaking in a familiar language compared with the choppy thinking/translating required to speak in a foreign language.
Reply | Report Abuse | Link to this@unrealpotboy
Reply | Report Abuse | Link to thisThe definition of terms is precisely where laypersons, the media, and scientists have a disconnect, leading to ambiguity, misunderstanding, and confusion. Not just here, but in most other major scientific news items, and especially in "controversial" ones like evolution. You can see it all through these comments -- people referring to "tasks" that are not really the "tasks" as defined in the study.
ugh! so frustrating!
I would suggest that chewing gum is not a CONCIOUS activity that requires concentration as say texting while driving. The article was specifically about switching between concious activities. I would hope that one would not have to concentrate on eating and breathing simultaneously. Fortunately this is not necessary due to the autonomic nervous system.
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