In September last year, UK broadcaster, Radio 4, transmitted an interview with Jo Boaler, a professor of maths education. I remarked on this at the time on my old blog. There were a number of claims that I disagreed with but one claim stood out as simply very strange.
Boaler stated that, “One of the recent studies showed us that when you make a mistake, your brain grows.” She then equated the firing of synapses with the brain ‘growing’ and went on to explain that, in the study, there were two bursts of synapse firing, with the first occurring before the participants knew that they had made a mistake.
Sarah Montague, the interviewer, was surprised by this. “How on earth can that be?” she asked. “If you don’t know you’ve made a mistake, why should a synapse fire…?”
It’s a good question and, at the time, I wrote that I would love to read the study in question.
I was reminded of this when I saw a new video that Jo Boaler has produced to explain the idea of a growth mindset to students (a video that coincides with the release of her new book; a book that I’m happy to review if anyone wants to send me a copy). She makes a very similar claim. “A research study found that when people make mistakes their brains grew more than when they got work right.” Again, referring to the firing of synapses, she states, “The first comes when you make a mistake and the second comes if and when you’re aware that you’ve made a mistake.”
This time, one of her students has the role of asking the obvious question, “But how can your brain grow if you don’t know you’ve made a mistake?”
Boaler replies that, “Your brain grows when it makes a mistake because it’s a time when your brain is challenged and struggling.”
I went back to my old post and, in particular, a comment from “Luke” who located the study in question. Boaler had mentioned the paper on Twitter when asked about it by Daniel Ansari. It is a 2011 article by Moser et. al. and is freely available on-line so you can read it for yourself.
In this experiment, 25 participants have to pick out whether the central letter in a string of letters is congruent with the surrounding or ‘flanking’ ones. It is an example of a flanker task. Two letter are used for each trial. For example, in the first trial, “M” and “N” are used. The string “MMMMM” is congruent and “MMNMM” is incongruent. It took me a while to get my head around this. Surely, this is the easiest task ever? Then I realised that the participants are under severe time pressure.
I am not a neuroscientist so forgive me if I misrepresent some of the subtleties in what I am about to explain. The participants had electrodes attached to their heads to measure electrical activity known to occur in the processing of mistakes. Note that they do not measure other brain activity. This means that the fact that they found more activity when participants made mistakes is both unsurprising and a finding that does not rule out the possibility that there was even more activity of other kinds in other areas of the brain when participants got the answers correct. Also, recording a voltage in this way is not the same as concluding that the brain has ‘grown’. Yet brain growth is the repeated claim.
The fact that one of these electrical bursts – the “Error-related negativity” (ERN) – occurs before participants are aware of their mistake now seems less mysterious. As the paper explains:
“Current conceptualizations suggest that the ERN and the Pe are dissociable neural signals involved in error processing, with the former reflecting conflict between the correct and the erroneous response and the latter reflecting awareness of and attention allocation to errors.”
Clearly, the participants have all of the information that they need in order to figure out if they are right or wrong – they don’t need any external feedback. This is one of the reasons that the researchers chose this particular task. It is quite possible that some of this is processed unconsciously before the participant becomes aware of the mistake. I sometimes ‘feel’ something when I write a typo before I realise exactly what I have done and I put this down to subconscious processing.
If you mine the references of the Moser paper, you eventually arrive at this paper by Nieuwenhuis et. al. (2003) which seems to be the source of a stronger claim. In this case, participants completed a ‘antisaccade test’ and the researchers found the ERN response even when the participants were unaware that they had made an error (although it was weaker than if they did become aware). However, it is worth looking at Wikipedia’s description of an antisaccade test:
“To perform the anti-saccade task, a patient is asked to fixate on an motionless target (such as a small dot). A stimulus is then presented to one side of the target. The patient is asked to make a saccade [eye movement] toward the opposite direction of the stimulus. For example, if a stimulus is presented to the left of the motionless target, the patient should look toward the right. Failure to inhibit a reflexive saccade is considered an error.”
So the purpose is to resist a reflex. Again, although not consciously aware, the participants do have access to the information that they need to determine whether they have made an error. So it is possible that they are processing this unconsciously.
The ERN is interesting and the literature on it contests whether it really is about error processing or noticing conflict. However, these particular experiments seem very far removed from somebody solving a typical school maths problem, making an error, not realising they have made an error and having their brain grow in response. Which was the meaning that I had taken from Boaler’s statements.
The new video also adds another layer to the brain growth argument.
“Your brain is like a muscle,” we are told, “the more you exercise it, the bigger it gets.” This is an alarming prospect given that our skulls are a fixed size.
We are then introduced to Cameron, a little girl who had the right hemisphere of her brain surgically removed in order to treat a rare disease that produced violent seizures. Boaler’s students inform us that, “The doctors expected Cameron to be paralysed for a long time, maybe forever because she lost part of her brain that controls physical movement. But she shocked doctors and scientists as, within months, she was running around again.” Apparently, “the doctors could only conclude that the missing side of her brain had, in effect, regrown.”
It is not hard to research Cameron’s story. This news report contains a quote from Cameron’s surgeon:
“We like to do children because of their ability or their plasticity — that’s the ability of the other side of the brain that we haven’t removed to take over and control the function of the diseased half we’re removing,”
So it seems that the doctors expected Cameron’s left hemisphere to take over. They weren’t shocked by this at all. Indeed, it is unclear why anyone would want to perform such surgery without expecting a positive outcome. And it doesn’t sound like the brain had ‘in effect, regrown’. Instead, the left hemisphere rewired itself to take over some of the functions of the missing right brain.
In this piece on the University of New South Wales wikispaces, there is a much more detailed discussion of the case. It seems that there have been similar cases before, enough that, “The neurosurgeon, Dr. George Jallo was confident that Cameron would make a full recovery after the hemispherectomy. This surgery can be performed successfully on children because of the ability of the remaining hemisphere to compensate for the removed, diseased hemisphere,” and that, “Children who have undergone hemispherectomies are often able to regain the ability to talk and walk, although fine motor control of the contra-lateral side remains impaired.”
In short, these are all very odd pieces of evidence to use in order to make the claims that Boaler makes. I do understand that the new video is intended for children but, as I noted at the start, similar claims have been made in other forums.
Can your brain ‘grow’ in the way Boaler describes? Only if you consider electrical activity in the brain – which every living person has – to be ‘growth’ or the ability for a child’s damaged brain to rewire itself to be ‘growth’.