BBC BLOGS - Fergus's Medical Files
« Previous | Main | Next »

Can electricity boost maths skills?

Fergus Walsh | 22:49 UK time, Thursday, 4 November 2010

A shocking idea or a spark of genius? Scientists in Oxford say applying an electrical current across the brain may be able to enhance your mathematical abilities.

The amount of electricity is tiny - one thousandth of an amp. The electrodes are placed at the back of the head over the parietal lobe.
This is an area of the brain which is a crucial in acquiring mathematical skills. Those with dyscalculia, sometimes called maths dyslexia, often have abnormal function of the parietal lobe.

The researchers found that if the current flowed from the right of the brain to the left, then mathematical ability was enhanced. If it was reversed then it impeded learning, so that the volunteers scored no better in puzzles than a six year old.

This was a very small study with just 15 volunteers who spent many hours solving mathematical puzzles. Much bigger and more detailed research is required before any robust claims can be made about the electrical stimulation and maths ability.

Dr Roi Cohen Kadosh a cognitive neuroscientist at Oxford University kindly allowed me to take the device onto the streets of the city this lunchtime. I interviewed an entirely unscientific handful of students. I was surprised at how many were keen to give it a go, although the experiments have to be done under strictly controlled conditions in the laboratory.

One of my first questions for the scientists regarded left handedness. As a left hander I wanted to know if the current needs to flow the opposite way in order to enhance maths ability. Dr Cohen Kadosh and his postgraduate researcher are also left handed "We excluded left handers from the trial", said Dr Cohen Kadosh, "in order to get rid of a variable which could have affected the results". No doubt in future trials left handers will get their chance.

I was allowed to try out the device in the lab. I had to put on a rather natty black sports headband - the kind that John McEnroe used to wear at Wimbledon. This was purely to hold the electrodes in place. When the current was switched on I am afraid I did not feel a sudden rush of genius. In fact, I did not feel anything at all. Not a jot, not a spark, not even a mild tingling sensation. Proof, some will say, that there is nothing much between my ears.


or register to comment.

  • 1. At 01:39am on 05 Nov 2010, Lewis Standing wrote:

    Why any trial, with any results no matter how significant or impressive, with a number of 15 participants is deemed national news I'm afraid I will never quite grasp. Because simply such a small study couldn't prove a single thing and is so statistically low powered that in essence, it is useless.
    I also don't like how these research findings never give explicit details of the original paper, Ie. a real reference. How can anyone possibly make their own mind up on the subject if all they get exposed to is a headline? The researchers own conclusions never mentioned and how far these can be extrapolated with the strength of the statistical difference between each variable. The media, it seems thinks such essential details are above us and the relentless sensationalist journalism continues. Here is the message I took home after seeing this on the news; "No need to try to master mathematics kids, in fact what you really need to do is to get a small current flowing through your head, you don't even have to try".

    Well I'm afraid to say that I do not require a milli amp in any vector flowing vaguely through my skull to work out the shoddy journalism that has followed this potentially interesting topic.


    Complain about this comment

  • 2. At 01:59am on 05 Nov 2010, Mwbar1 wrote:

    Aaaahhhhhh Lewis Lewis Lewis....... you have fallen into the trap of expecting the media to act in it's audience's interests rather than it's own.

    Complain about this comment

  • 3. At 02:03am on 05 Nov 2010, SimonLockhart wrote:

    The article was interesting, but in the second paragraph it is stated that "The amount of electricity is tiny - one thousandth of an amp".
    Amperage is almost meaningless in this context without voltage - 1/1000 of an amp could provide a large amount of power if twinned with a high voltage. I don't imagine this to be the case, but if technical data are to be given at all, they need to be given in a way that imparts useful information.
    Other than that I enjoyed it. It's well-written and accessible and hopefully more articles like these will spark people's interest in the sciences.

    Complain about this comment

  • 4. At 04:17am on 05 Nov 2010, Lars Of The Mohicans wrote:

    If you want to educate the public about science, hire a real scientist. Otherwise, focus on what you know best BBC, politics and weather. The public is already inundated with enough crap about science, courtesy of ted dot com and other similar "look at me, I too can do science" websites.

    Complain about this comment

  • 5. At 07:10am on 05 Nov 2010, zebedee wrote:

    But is this the direction of conventional current (+ve to -ve) or directions of electrons (-ve to +ve) ?

    "if the current flowed from the right of the brain to the left, then mathematical ability was enhanced"

    Complain about this comment

  • 6. At 07:57am on 05 Nov 2010, Jason wrote:

    SimonLockhart, I'm not sure you understand how electricity works. The voltage and current aren't two independent variables, they're related to each other by the resistance (Ohm's Law).

    If you keep the resistance the same (ie, in this case same body and placement of electrodes) then increasing the voltage would increase the current.

    Complain about this comment

  • 7. At 08:50am on 05 Nov 2010, Mr Wonderful wrote:

    I have really missed out in my career choices, as these 'research' projects are all funded by some organisation (probably Duracell in this case) and the resulting 'journalism' funded by the licence payer. Easy money in either case, and not much need for rigour.

    Any time I see or hear so-called scientific reporting from the BBC, my heart sinks, especially when the ill-informed use of statistics appears. The habit of making or repeating claims without references, sources or evidence is the nursery of the urban myth, invariably stating a negative phenomena, such as domestic violence, obesity, poverty, ginger hair etc., etc.

    Complain about this comment

  • 8. At 08:58am on 05 Nov 2010, tony wrote:

    Curiously I was exceptionally good at mental arithmatic when I was young.My first clear memory was an immense electric shock accompanied by an everlasting vision of my grandfathers living room as I pushed my tiny fingers into an old fashioned plug socket. I was probably 2 years old.

    Complain about this comment

  • 9. At 09:39am on 05 Nov 2010, Isaac wrote:

    "SimonLockhart, I'm not sure you understand how electricity works. The voltage and current aren't two independent variables, they're related to each other by the resistance (Ohm's Law).

    If you keep the resistance the same (ie, in this case same body and placement of electrodes) then increasing the voltage would increase the current."

    While correct in itself, this is missing Simon Lockhart's point. He's saying they have not given us enough information to know the power. All they would need to tell us, for us to know this, is the voltage, but as he says they haven't told us this. (We could also work this out from the resistance, too, if they choose to inform us this way, but the point is we don't have enough information to know the power.)

    Complain about this comment

  • 10. At 10:39am on 05 Nov 2010, adam wrote:

    Electrical power is P=V*I (with V as Voltage and I as current, as you probably all know). But with small currents we can also assume Ohm's law V=IR too (where R is the resistance of a of the head between the elctrodes). Hence we can rewrite the power as either P=I^2*R or P=V^2/R. If we assume the resistance, R of a human head is roughly equal for all human subjects, then we only need to know either I or V.

    Complain about this comment

  • 11. At 11:51am on 05 Nov 2010, jizzlingtons wrote:

    Firstly, you can't apply Ohm's Law to a human head. There are way too many variables, and an assumption of constant resistance is simply not appropriate.

    Secondly, regardless of the technical accuracy of SimonLockhart's comment, his point was completely valid in that the article attempts to describe current as a measure of electric power, this is not a suitable description of the level of electricity applied.

    Thirdly, 1 milliamp is a significant level of current. Most electronic circuits operate with various current flows in the region of a few milliamps - and it doesn't take much to fry them. The idea of having a few milliamps passing through the cells in my brain certainly does not appeal to me, and I would have thought would be a lot more dangerous than this article suggest.

    Also, where is the proof that any of this current actually passed through the brain? Were the electrodes inserted directly into the brain? Or perhaps the current flow was around the skin?

    Finally, I would agree with others that this seems to be spilling out the headline story without any thought into the study itself. Only 15 people? Has a paper been published on the study? If so where are the references?

    Complain about this comment

  • 12. At 11:52am on 05 Nov 2010, Commanche wrote:

    Adam, by adding another variable, has shown that we need to know the resistance to work out the power and the only way to know that is to either measure the actual resistance across the parietal lobe or know the Voltage used to get the 1mA current.

    Generally the story is interesting if not particularly enlightening.

    Complain about this comment

  • 13. At 11:54am on 05 Nov 2010, Peter_Sym wrote:

    #4. Totally agreed. Once upon a time the BBC had stuff like tomorrows world and even more recently 'rough science' where people with doctorates in science and engineering talked about science in an approachable way. Now we have 'bang goes the theory' where failed breakfast TV presents (last time I saw Liz Bonin was on 'Rise' 8 years ago) do pointless experiments with no clear aim. TONIGHT! We see if its possible for a plane to fly on just a jet of air!!!!..... (and when we fail to achieve our aims we'll just gloss over the 50 year success of the Hawker Harrier)

    To be fair Fergus's blog is usually much better than this but it does have a habit of being hijacked by scaremongerers. My favourite was during swine flu when various people claimed the adverse effects of the vaccine were being hidden by the pharmaceutical industry. When I pointed out that 'adverse effects of swine flu vaccine' first google hit is the leaflet provided by Glaxo-Welcome in their vaccine pack on their own website which stated >1 in 10,000 chance of paralysis or death I was told 'how are normal people meant to get that information'???? Quite.

    Complain about this comment

  • 14. At 12:35pm on 05 Nov 2010, peteloud wrote:

    If a little electricity through the brain makes a person a little smarter, I'd like to see them try and make Tony Blair very, very smart.

    Complain about this comment

  • 15. At 1:11pm on 05 Nov 2010, DJM wrote:

    Fifteen subjects could produce a reliable result. It all depends on the size, consistency of the effects and the experimental design. To evaluate this it would be helpful to have information on a statistical analysis. Also, there have been several other reports documenting the effectiveness of DC current in facilitating/inhibiting cognitive skills, depending on polarity.

    Complain about this comment

  • 16. At 1:47pm on 05 Nov 2010, Megan wrote:

    Having, many years ago, trained as a research scientist, may I add my voice to the pleas above: where is the paper on which the report is based? Without knowing precise details it is difficult to do more than say 'Oh, how interesting...' before moving on to another story. One would imagine it's somewhere in the literature, properly peer-reviewed (at least, I'd hope so if it's deemed appropriate to notify the media about the research)... but where?

    Complain about this comment

  • 17. At 2:14pm on 05 Nov 2010, SimonLockhart wrote:

    As most people noticed, the word I used was "power" and my sole point was that one cannot calculate the electrical power from a single value - in this case, the voltage. As you said, Jason, it's the most basic application of Ohm's law.

    peteloud , I like it!

    Complain about this comment

  • 18. At 3:08pm on 05 Nov 2010, sensiblegrannie wrote:

    ZAPPING the brain is an old idea and it used to be used as part of a 'cure' for certain mental conditions. Now they are considering using it to improve maths skills. I can just picture it........Jimmy, your maths results are very low this week either you havn't being paying attention or you need electric shock treatment.
    I am left handed and my maths skill are less than perfect, but I think I will stick with the problem rather than get my head toasted. Mind you, a couple of trickle feed solar panels fitted to a hoodie or a baseball cap might be less scary and perhaps they would become a fashion item in time.;-)

    Complain about this comment

  • 19. At 4:09pm on 05 Nov 2010, a yank wrote:

    As a left handed person, can I be considered already in my "right mind ?" The next fifteen subjects should exclude right handed people as a variable to exclude.

    Complain about this comment

  • 20. At 4:29pm on 05 Nov 2010, Shaken and Stirred wrote:


    10000 amps should be a suitable starting point, though as the head is quite empty then the resistance will be high. Are there enough volts available?

    Complain about this comment

  • 21. At 4:36pm on 05 Nov 2010, number_cruncher wrote:

    Link to full text paper:

    I'm not much convinced by the bad science/reporting arguments here. To take some of the points raised in the comments:

    * Yes, this is a small trial. Small trials are conducted before large trials because large trials are eye-wateringly expensive to run. So running a smaller study before a larger one to see if there's something worth investigating in a larger trial seems to me to be eminently sensible. Note that the study did obtain statistically significant results.

    * As for the notability criterion, I think the fact that the improvements are sustained makes it sufficiently noteworthy for reporting on a national news website. And let's be honest, who wasn't at least a little bit tickled that you could make people worse at maths by reversing the polarity?

    * The article reports the current delivered (good! It gives a sense of scale). Current is the important variable here, and it's the one held under control. Argue about Ohms Law and power all you want; skin is still non-ohmic, and the relationship between current and voltage non-linear, so you can't just do a simple wee sum and expect to calculate how many volts you need to get 1mA. You need to gradually raise the voltage from from zero until the measured current flowing hits 1mA, and then adjust voltage to hold current steady from there (this will be done automatically by the equipment).

    The voltage used to induce 1mA current will be different for each person, and could even change over time (what if a subject starts sweating more or less?), so it would be inappropriate to report a single figure for voltage (and in any case wouldn't be particularly relevant to anything the original journal article was reporting).

    * Not providing a reference. OK, I agree with this one, but it may not be quite the mortal sin it first appears; the paper has passed peer review but hasn't actually appeared in the journal yet (making citing it a little trickier).

    It IS available online however, and the page has a handy "Export Citation" button to take all the work out of citing it correctly:

    Roi Cohen Kadosh, Sonja Soskic, Teresa Iuculano, Ryota Kanai, Vincent Walsh, Modulating Neuronal Activity Produces Specific and Long-Lasting Changes in Numerical Competence, Current Biology, In Press, Corrected Proof, Available online 4 November 2010, ISSN 0960-9822, DOI: 10.1016/j.cub.2010.10.007.

    Okay, not including the reference seems pretty bad, but given it's yet to appear in the journal itself, it's plausible the BBC weren't aware it was available online and/or didn't know how to cite the paper or thought it unnecessary in these circumstances. (If this is the case, it would be lovely if the BBC guidance on citations could be looked at to see if it deals with articles yet to appear as well as it could.)

    Some of the comments here (not necessarily the ones I'm referring to above, I hasten to add) display a deeply unflattering mix of ignorance and invective, trivialising a genuinely fascinating and potentially important result and (for the most part) unfairly bashing BBC journalists (who have written a reasonable piece for a general audience, a.k.a. "their jobs").

    Complain about this comment

  • 22. At 4:59pm on 05 Nov 2010, a yank wrote:

    Publish or perish

    Complain about this comment

  • 23. At 6:26pm on 05 Nov 2010, aa42john wrote:

    Re sample size = 15

    Yeah, the sample size is pretty small. But (give or take a few simple assumptions) even a sample size of 5 allows you to say with 94% confidence that the true average lies somewhere between the highest value and the lowest value. The other 6% is a small probability, akin to the 6.4% probability of getting either 5 heads or 5 tails when you toss a coin 5 times.

    With sample size of 15, the confidence level will be higher than 95%. This is all explained in many stats textbooks, and at the website - see

    Complain about this comment

  • 24. At 00:41am on 06 Nov 2010, John wrote:

    A sample size of 15 is small, however, if effect size is large when looking at the difference using the equipment and not, it is possible to have a statistically significant result. It would of course be important to consider how participants were sampled and other factors, this is why details of the relevant paper should be given.

    Complain about this comment

  • 25. At 05:16am on 06 Nov 2010, Lawrence Paros wrote:

    This comment was removed because the moderators found it broke the House Rules.

  • 26. At 05:23am on 06 Nov 2010, Lawrence Paros wrote:

    Re enhanced cognitive functioning and CES (cranial electrotherapy stimulation), I should like to call to the skeptics' attention the following: Thirteen studies, in which a total of 648 patients with various types of cognitive dysfunction were treated with cranial electrotherapy stimulation (CES), were combined statistically in order to get a more confident look at the effectiveness of CES for treating this condition. While many of the studies were of the classic double blind protocol, others used either the single blind or open clinical trial. The result of the analysis showed that the overall effectiveness of CES was 44% improvement. When the 7 studies of patients with substance abuse and the 3 studies of fibromyalgia patients were analyzed separately it was found that the substance abuse patients averaged a 60% improvement, while the fibromyalgia patients gained a modest but significant 17%. The results indicate that a different etiology is most likely driving the cognitive dysfunction in the two. Perhaps in one group a more basic physiological change was at work due to the history of substance abuse, while the fibromyalgia patients may have simply been driven to cognitive distraction by their intractable pain. Elsewhere it was noted that the “permanent brain damage” that was said to be a condition of long term substance abuse patients as late as the 1980s, has now been seen to return to within normal functional limits following 3 weeks of daily CES treatment. Full documentation for the above is available on request.

    Complain about this comment

  • 27. At 10:33am on 06 Nov 2010, sensiblegrannie wrote:

    post 26 Lawrence Paros
    It doesn't matter how well you dress it up, a pigs ear is a pigs ear. Fine feathers make fine birds and fine words make barbaric ideas sound reasonable. Do cerebral aneurysms result as a side effect of overuse of CES or could CES be used inappropriately as a result of symptoms of a cerebral aneurysm?

    Complain about this comment

  • 28. At 10:34am on 06 Nov 2010, Megan wrote:

    Thank you, number_cruncher, for the links.

    And yes, please, Lawrence Paros - I'd be interested to see further details of the studies you are talking about.

    Complain about this comment

  • 29. At 10:54am on 06 Nov 2010, sensiblegrannie wrote:

    E.C.T. Electro Convulsive Therapy......check it out and compare it with this current study (no pun intended)

    Complain about this comment

  • 30. At 1:36pm on 06 Nov 2010, BluesBerry wrote:

    Well, I reckon you still got most of the question that you came in with: Can electricity boost maths skills?
    Those with dyscalculia, sometimes called maths dyslexia, often have abnormal function of the parietal lobe. I didn't know that!
    The researchers found that if the current flowed from the right of the brain to the left, then mathematical ability was enhanced. If it was reversed then it impeded learning, so that the volunteers scored no better in puzzles than a six year old. Hmmmm...Interesting.
    The reason I say you're primarily right back with your starting question is of couse sampling size: 15 volunteers who spent many hours solving mathematical puzzles.
    However, I know that the brain functions on signals - electrical signals that cross synapses; therefore, I believe that electrical stimulation to malfunctioning or non-functioning parts of the brain has definite promise.
    Also, that's an interesting follow-up question re lefties; I'm curious. What was the reason, do you think, that when the current was switched on the subject did not feel a sudden rush of - if not genius - than something?
    I think this research has got quote a wide-field of promise, but I am way ahead of myself on stroke victims, autistic persons, any physical problem that might be impacted by those electrical signals not smoothy crossing synapses.

    Complain about this comment

  • 31. At 4:37pm on 06 Nov 2010, dee andrew wrote:

    The next thing we will be hearing is that microwaves make you cleverer!
    Two things that will help your maths:
    1. learn your times tables so you get a really good feel of numbers.
    2. keep away from wireless sources such as mobile phones, WiFi etc. as I have reason to believe that these mess up the brain's function.

    And how on earth you can go shopping and not realise you have over-spent, well is this what has happened to the whole nation the last 10 years including the government? Are we all suffering from dysculculia?

    Complain about this comment

  • 32. At 4:52pm on 07 Nov 2010, GeoffWard wrote:

    Can I ask about the proportion and absolute numbers of the BBC Editors that have an (i) Arts degree (ii) Science degree?

    ..just ball park figures will do, so we can see the ability of the journalistic team to present science effectively without falling into schoolboy errors.

    Complain about this comment

  • 33. At 01:58am on 08 Nov 2010, goodb6attery wrote:

    This comment was removed because the moderators found it broke the House Rules.

  • 34. At 09:51am on 11 Nov 2010, Ken Matthews wrote:

    They say that nothing in the world is new... Here is a true incident that occurred in the 1950's and directly relates to these experiments. Well, in a manner of speaking...
    Go to and click on "The Connection".

    Complain about this comment

View these comments in RSS


Sign in

BBC navigation

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.