[chris (OP)]

Paul has been in touch with feedback relating to an item covered recently on the podcast regarding the brain's ability to multitask.

I enjoy podcasts of your programmes in Australia. Thank you.

Recently you did a segment on the psychological idea of multi tasking in response to a listener question, can it be improved.

I was disappointed to hear your guest presenter perpetuate this myth.  Perhaps you could do a myth conception on the subject.  May I refer you to the work of Daniel Levitin, a neuro scientist.  Basically the brain doesn't do 2 or more tasks at once, what happens is that the brain switches between task.  The switch is located in the top of the brain in the insula.

Further, if you do a lit-review you will find ample studies showing that this switching mechanism which uses high volumes of glucose, shows that switching is the least productive use of time and that staying with one task not only produces much better work, e.g. deeper understanding, it is much more productive.

Another of the negative side effects of constant switching is that it burns a lot of glucose, the brain's food, on a low beneficial outcome activity, leaving less for  beneficial functions. 

So the answer to your listener's question is, no matter how good someone at switching, stop it, stop engaging in this activity which is based on a silly myth.
Regards Paul

[chris (OP)]

Dr Duncan Astle, who answered the question on the programme replies:

I wonder whether we are meaning ‘multi-tasking’ in two different ways. On the show, I was just describing a behaviour, rather than making any specific claim about the underlying cognitive or neural mechanism.
 
We multi-task all the time – it is merely a common term for actively pursuing multiple goals over brief periods of time. I wasn’t implying anything specific about the mechanisms governing this behaviour. How the cognitive system configures itself to best achieve the multiple desired outcomes is keenly debated. For example, resources could be divided across multiple routines in parallel, alternatively subjects could allocate resources dynamically in a moment-to-moment fashion, essentially switching priorities rapidly. These accounts are not necessarily mutually exclusive: the underlying mechanisms governing multitasking may be heavily influenced by participants’ strategies, ability and the nature of the tasks involved.  But importantly, regardless of whether subjects ‘switch’ or run tasks in parallel, it is still multitasking. (In terms of mechanisms I think you are probably right, there is a dynamic switching of resources between the different tasks).
 
I totally agree that our performance will always be superior when we focus on one task at a time. But in everyday life this is not always possible, which is why multi-tasking has been such an area of interest for cognitive psychologists. Interestingly, our ability to multi-task (however we do it) can be trained. For example, Anguera et al (2014) showed that multi-tasking performance could improve dramatically with training, with the benefits extending to untrained tests of attention and memory in older adults. This is an area of great promise, because multi-tasking is important in everyday life and is prone to age-related decline.
 
Anguera, J. A., Boccanfuso, J., Rintoul, J. L., Al-Hashimi, O., Faraji, F., Janowich, J., ... & Gazzaley, A. (2013). Video game training enhances cognitive control in older adults. Nature, 501(7465), 97-101.

Dr. Duncan Astle
Programme Leader, MRC Cognition and Brain Sciences Unit
Research Associate, St. John’s College, Cambridge

[chris (OP)]

We also heard from Kamil, in Poland, who says:

Hello Naked Scientists,
I am a huge fan of the show for years. I really love the show and glad to have one so scientifically heavy podcast. You do extremely good work with bringing most complex problems and talking about them in such simple language.

I also Iike very much your relatively new segment myth conception.

Anyways on the last show there was a question regarding multitasking and I'm afraid the guest's answer was far from correct. He answered that practicing make you good at anything even multitasking and yet this is something opposite to all what I know from psychology to neuroscience. We can't really pay attention to more than a one thing we can switch attention but it costs the quality of our performance in those tasks.

Sometimes I'm afraid you also trust some bad studies like those where, allegedly, meditation makes some special thing a to your brain or marijuana treating properties.

Cochrane doesn't support these claims saying most of meditation studies is simply bad science and marijuana has no benefits other than you get from any drug that gets you high, it doesn't cure your cancer, it helps you deal psychologically with chemotherapy. BTW I'm all for studying and using marijuana in medicine. However calling THC the medical marijuana is like calling morphine the medical opioids.

I know you have tons of questions and shows. Love them all. But please, don't answer a question if you don't have enough time to deal with it with a very deep understanding.

Kind regards,
Big fan of the show,

Kamil

[chris (OP)]

Dr Duncan Astle has replied:

Dear Kamil,
Always happy to take questions on task-switching and multi-tasking. It is one of my favourite areas of cognitive psychology and neuroscience… so much so in fact that I did a PhD on that exact topic!
 
I wonder whether we are talking about two different things here. Firstly, you are absolutely correct in saying that attempting to achieve two goals at the same time will be far less efficient than taking each goal in turn. You will see this as a cost in performance – subjects will become substantially slower and more error prone. However, in many cases we have little choice but to engage in multi-tasking activities, which is why it is one of the most popular topics in cognitive psychology and neuroscience. For example when first learning to drive, learners must juggle the various concurrent demands – checking mirrors, spatial awareness of other cars, indicating, changing gears, tuning the radio (joke) etc. In my answer I was not for a second suggesting that multi-tasking will make you *better* at performing the tasks relative to performing those same tasks separately; doing two things at once will always be worse than doing one thing at a time. 
 
Instead I was specifically claiming that where we are engaged in some multi-tasking scenario, practice will improve our performance at multi-tasking. This is very much correct. For example, Anguera et al. (2014) show that with training, elderly adults demonstrate very substantial improvements in multi-tasking. This is presumably because they get better at managing the very process of allocating resources to the two tasks, because control groups who just practiced on the individual tasks did not show the same multi-tasking improvements. These benefits transferred to untrained measures of attention and memory (although it is worth noting that these far generalisation effects are a little controversial).
 
As for marijuana and meditation, my knowledge of those areas is less well developed, although I would suggest trying neither whilst driving.
 
Best,
Duncan
 
Anguera, J. A., Boccanfuso, J., Rintoul, J. L., Al-Hashimi, O., Faraji, F., Janowich, J., ... & Gazzaley, A. (2013). Video game training enhances cognitive control in older adults. Nature, 501(7465), 97-101.

I hope that's helpful, Kamil.

[MayoFlyFarmer]

Everything I have read supports the initial poster's comments that the human brain cannot physiologically focus on more than one thing at a time. But as we all know from daily life, and as the second poster points out, we the physiological inability to multitask doesn't prevent the functional act of multitasking (due to "switching" as noted in both posts, meaning that we basically operate similar to a PC running Windows 95).  In the end, its really a matter of semantics, and what you consider "multitasking".  When it comes to "functional" multitasking, I read an interesting study once that found there was very little difference between most individuals and their ability to functionally multitask, even though there was a large disparity in how people perceived their own ability to multitask.  That study (which I wish I could find now) found that the differences in one's confidence to multitask actually stemmed from differences in perception of who well one was performing the tasks they were performing.  Simply put, everyone's performance dropped when concentrating on multiple activities at once, but some people realized it (and claimed to have poor multi-tasking abilities)  while other people convinced themselves that they were still performing the tasks at a high level and therefore claimed to be excellent multi-taskers.  Just one study though, definitely not the end-all be-all in the field.