Dr Caroline Leaf – credit where credit’s due


It’s not often I see something positive in Dr Leaf’s work, but today was one such occasion.

I’m often (legitimately) critical of Dr Leaf’s paucity of references and citations for her Facebook posts and social media memes.  Today was different – Dr Leaf made a statement and backed it up with an easily obtainable peer-reviewed journal article.  It’s a shame it wasn’t backed up by an accurate interpretation, but it’s a positive step none-the-less.

Dr Leaf claimed that “People who served others experienced a 68% increase in healing compared to those who only got treatment for themselves.”

Since the article was so easy to find, I decided to look it up.  The article was by Poulin et al, “Giving to others and the association between stress and mortality”, in the American Journal of Public Health [1].  Actually, the article was familiar, because Dr Leaf has written about the same article before, but her social media post that time was more nebulous.

So does the study by Poulin and his colleagues show that people who served others experienced a 68% increase in healing compared to those who only got treatment for themselves?  In a word … no.

First of all, the study wasn’t looking at healing, it was looking at mortality.  They may seem similar, but getting better from something (“healing”) is not the same as not dying from something (“mortality”).

Second, no one in the study was being “treated”.  I’m not sure where Dr Leaf got the idea that the control group was getting “treatment”.  The study compared those who self-reported “helping behavior directed toward close others … in any of 4 unpaid helping activities directed toward friends, neighbors, or relatives who did not live with them” versus those that did not.

Thirdly, there’s no mention of a 68% improvement anywhere in the article.  The article gives its results as hazard ratios.  For the non-statisticians, the hazard ratio is “the ratio of the particular event taking place in treatment group compared to control group.”  The simplest (probably over-simplified way) way of thinking about hazard ratios is to do a simple sum – the hazard ratio minus 1 is the percentage increase or decrease in risk, where a positive number is an increased risk and a negative number is a decreased risk.  So a hazard ratio of 1.13 means that a person in the exposure group has a 13% increased risk compared to the control group (=1.13 – 1).  And a hazard ratio of 0.7 means a 30% decreased risk (0.7 – 1 = -0.3).  So for the helping group to have a 68% decreased risk of dying, the hazard ratio would be 0.32 (0.32 – 1 = -0.68).

If you’re lost in the numbers, don’t stress.  The point is that Dr Leaf was very specific about the helping group increasing in healing by 68%, but there’s nothing in the results to suggest this.  The study authors wrote, “When we adjusted for age, baseline health and functioning, and key psychosocial variables, Cox proportional hazard models for mortality revealed a significant interaction between helping behavior and stressful events (hazard ratio [HR] = 0.58; P < .05; 95% confidence interval [CI] = 0.35, 0.98). Specifically, stress did not predict mortality risk among individuals who provided help to others in the past year (HR = 0.96; 95% CI = 0.79, 1.18), but stress did predict mortality among those who did not provide help to others (HR = 1.30; P < .05; 95% CI = 1.05, 1.62).”  Unless I’m missing something, there’s nothing in the results that remotely suggests a 68% improvement in anything.

And for what it’s worth, the study shows very weak associations anyway (in statistical terms, the confidence intervals are broad, and almost cross 1), so even if the study really did say something about a “68% increase in healing”, it’s something that is only slightly more likely to occur than by chance alone.  Then there’s other evidence that contradicts this particular study’s findings, so in all fairness, this study shouldn’t be used to base social media memes on in the first place.

Overall, it’s good that Dr Leaf cited an article in her social media meme, but her interpretation of the study was poor, something more at the level of a university freshman than a supposed expert in her field.  And it reflects badly on the Christian church that this is the level of ‘expertise’ that the church accepts and then promotes.

I would encourage Dr Leaf to continue to cite references for her memes, but she really needs to learn how to interpret clinical studies if she and the church are going to continue to promote her as some sort of expert.


[1]        Poulin MJ, Brown SL, Dillard AJ, Smith DM. Giving to others and the association between stress and mortality. Am J Public Health 2013 Sep;103(9):1649-55.


Prescribing dangerous drugs for a made up disease

Honestly, I don’t know if I can go on much longer.

I feel like every time I approach the wild waters of social media, I find myself drowning in a sea of shameless ignorance.  It’s like a post-modern intellectual zombie apocalypse where brainless morons roam cyberspace, relishing the opportunity to infect the minds of the innocent and gullible with their delusions of expertise.

As I’m sitting here writing, the little angel on my right shoulder is trying to get my attention.  “Everyone’s entitled to their own opinion,” she whispers softly.

Except it’s hard to hear when the little devil on my other shoulder is digging his pitch-fork in my brain and twisting it to make a point.  “But their opinion is crap,” he angrily retorts.

Tonight, the subject of my inner voice’s great debate was the Facebook headline, “ADHD: Drugs to treat disorder could create heart problems for children, researchers say.  Children under 18 who had ADHD and were prescribed methylphenidate were more likely to get an irregular heartbeat in the first two months, researchers said.”

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The little paragraph on Facebook didn’t mention any important facts, like what the article was that they quoted, or that the actual number of events linked with drug were miniscule.

That didn’t stop some clearly stupid people from publically venting their rancid opinions all over social media.

There were the usual paranoid delusions claiming that ADHD is over-diagnosed so that the American Psychiatric Association could get more funding from pharmaceutical companies.  Or that Ritalin has never been properly tested, and that children on Ritalin have been human experiments for the last 30 years.

Then there were all of the old chestnuts too, like ADHD is because of poor parenting or poor diet, or teachers with sub-par intelligence who aren’t challenging their pupils enough.  And who needs Ritalin anyway when all you have to do is stop feeding them artificial flavours and colours, high fructose corn syrup, GMO’s and fast foods.  Better yet, treat them with cannabis.

There were also some brazen displays of intellectual impotence within the heady mix of stupidity, like the people who suggested that children shouldn’t be given ANY drugs unless they’ve got diseases like cancer.  ‘Cause, clearly, paracetamol and penicillin are just as toxic as Ritalin.

Then there was the cherry on top:

“The doctor who came up with ‘ADHD’ and ‘ADD’ confessed on his deathbed that they were made-up diseases.”

Really??  Oh, come on, that’s both pathetic and grossly insulting.  ADHD is a real disease.  It’s been proven by real scientists and real doctors working in real labs and real hospitals.  Yet in the post-modern mind-bubble, an unverified viral meme on social media carries more weight than decades of scientific enquiry by some of the worlds smartest people.

For those of us who aren’t intellectual zombies, there was no death-bed confession about ADHD’s concoction.  According to a fact-check by Snopes.com, the doctor who ‘made up’ ADHD never said ADHD wasn’t real, but only that he thought the biological cause of ADHD was over-estimated.

Those who clearly knew nothing about ADHD or its treatment decided to further perpetuate their ignorance by embellishing and catastrophizing the “heart problems” that the Facebook headline alluded to.  Except that if they had bothered to review the article Facebook was referring to, they would have seen that there really wasn’t anything going on.

According to the article “Cardiovascular safety of methylphenidate among children and young people with attention-deficit/hyperactivity disorder (ADHD): nationwide self controlled case series study” [1], the only significant heart issue with Ritalin is a condition broadly classified as ‘arrhythmia’, which is medical speak for an irregular heart beat.  However, the peak risk for arrhythmia in the study was in children with congenital heart defects in the first few days of treatment.  For this, the relative risk was 3.49.  That means that a child with an already dodgy heart will have a three and a half times greater risk of an irregular heart rhythm than a child with a normal heart who’s not on Ritalin.  This sounds terrible, but “lies, damn lies and statistics” – in reality, the overall number of children who will actually get an arrhythmia because of Ritalin is still incredibly low because the total number of children who get arrhythmias is incredibly low.  Mathematically speaking, 3.49 x diddly-squat is still diddly-squat.

Besides, all of this is old news.  The current study was simply trying to use a larger source of data to get better statistics on case-reports of the possible effects of Ritalin.  But in the product information of methylphenidate, heart problems are clearly listed as a possible complication.  Because of this, and to ensure that Ritalin isn’t thrown around like candy, only medical specialists like paediatricians and child psychiatrists can start a child on medications like Ritalin.

So the reaction to the new study is nothing more than a storm in a tea-cup, but it clearly demonstrates the stigma and ignorance towards ADHD that, I’m ashamed to say, still exists in our modern, progressive society.

Is it any wonder then that parents actively avoid getting an assessment for their struggling children, or do everything they can to avoid Ritalin even when they have a clear-cut diagnosis of ADHD?  ADHD causes enough suffering by itself, but the baseless and incoherent ranting of the uninformed masses adds stifling layers of unnecessary stigma and misery to those who deserve our support, not misleading advice or irrational judgement.


[1]        Shin JY, Roughead EE, Park BJ, Pratt NL. Cardiovascular safety of methylphenidate among children and young people with attention-deficit/hyperactivity disorder (ADHD): nationwide self controlled case series study. BMJ 2016;353:i2550.

Mobile phone mothering – one more thing for mums to feel unnecessarily guilty about

Mothers.  They are probably the single most important group of people in the world.

It’s not that I’m belittling the role of fatherhood, or demeaning the amazing work that fathers do for their children, but simply put, we wouldn’t be here if it wasn’t for the tireless patience and sacrifice of our mums.  Nine months of nausea, sore breasts, swollen appendages and having your organs used as punching bags.  Then there’s the trauma of birth itself, which is rewarded with the full-time care of a screaming, incessantly ravenous alimentary canal which has taken the form of a baby.  Over the years, the screaming and the pooping become slightly more manageable, but most mothers remain the head chef, playmate, laundromat, ironing lady, teacher, taxi-driver, nurse and drill sergeant for their offspring.

Despite these daily feats of amazement, most mothers are haunted by this nagging sense of not being good enough – Mother Guilt.  As author Mia Redrick wrote,

“Mother’s guilt is real. Nearly all of us experience it. We are racked with guilt, feeling that our best isn’t good enough. We struggle when work commitments prevent us from attending school events and we are crushed by the looks of disappointment on our children’s faces. We wonder if choices we have made, such as what school to send our kids to, have not had far-reaching negative consequences, if a different path would have resulted in happier, more well-adjusted kids. We moms might feel guilty when we can’t afford something for our kids or are nagged by the feeling that we simply don’t spend enough time with them.”

Mothers seems to feel guilty about anything, and everything, for the whole day …

“The kids are in the bed again. I was sure I shushed them back to their beds at 2am, they must have snuck in during the wee hours. Tonight I will make sure they sleep all night in their own beds. How will they ever learn to sleep if I keep letting them come in to my bed?”
“Whose children get only eight hours of sleep a night? I am sure at this age they are meant to be getting 12 – 14 hours sleep. I am going to damage then for life. Maybe I should let them sleep in my bed so they get more sleep?”
“Oh so much sugar in EVERYTHING.  Don’t you read the articles? Don’t you hear the “experts”? Don’t you see those diagrams with spoonful upon spoonful of the deadly substance displayed, a visual representation of poison imprinted on your mind each and every time you take the bran flakes from the cupboard?”

And so it goes on.

Today, Dr Leaf added one more thing for mothers to feel guilty about – smartphones.

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“Mothers, put down your smartphones when caring for your babies! That’s the message from researchers, who have found that fragmented and chaotic maternal care can disrupt proper brain development, which can lead to emotional disorders later in life.”

She then exhorted her followers, “Lets get some real eye-to-eye contact going – dads included!”

Dr Caroline Leaf is a communication pathologist and self-titled cognitive neuroscientist.  Credit where credit’s due – in the past, Dr Leaf has pathologically avoided citing her references, but today, she cited the article itself and the news story that promoted it.

But again, like the meme she posted a couple of days ago about sadness making people sick, Dr Leaf has posted the opening paragraph of a promotional PR puff piece and made it sound like a scientific pronouncement.  When you actually read the journal article that the news story is promoting, it has nothing to do with smartphones.  Or indeed, human beings.

The research was performed entirely on rats.

The research itself, by Molet and colleagues [1], seemed entirely legitimate.  The rat pups raised in a more chaotic way appeared to have higher levels of anhedonia, because they didn’t engage as much in the things that rats normally find pleasurable, namely, drinking sugar water or playing with their rat buddies.

I’m not sure if you’ve ever seen a mother rat on a smartphone.  I certainly haven’t, which means that news article Dr Leaf took her meme from, the one published on Science Direct, made some pretty tenuous assumptions:

  1. Chaotic mothering to rat pups is the cause of rat anhedonia
  2. Rat mothering and human mothering have similar outcomes
  3. Smartphone use causes fragmented and chaotic maternal care
  4. Not using smartphones would improve outcomes.

There’s no evidence from this study, or any work that I know of, that definitively proves any one of these things.  There are a number of alternative explanations as to why those rat pups weren’t as happy as the control group, but even if the chaotic nurturing of the rat babies was THE cause of their unhappiness, human beings are completely different to rats in cages.  And there are many things, other than smartphones, that can strain the mother-baby relationship.  Excessive mother guilt for one.

Dr Leaf’s meme is a good example of just how misinformation can spread quickly through the internet.  The PR department of a university writes a puff piece on the article to promote the university and its research.  But no one wants to read about depressed rats – they need a better hook.  There’s a love-hate relationship with smartphones in our culture, and lots of Mommy-guilt, so they use a sentence about smartphones and mothering to grab people’s attention, even though the journal article had nothing to do with either.

Science Direct then simply republished the press release from the university without filtering it, where it’s then picked up by wannabe scientists and self-titled experts like Dr Leaf, who pass on the misinformation to hundreds of thousands of their followers.  Pretty soon, mothers everywhere are feeling guilty about looking at their phone instead of their children’s eyes, when it probably doesn’t make a blime bit of difference.

The take home messages:

  1. Unless you’re a rat, there’s no evidence that using your smartphone makes you a bad mother.
  2. Be wary of social media memes, and what you read on the internet.
  3. Dr Leaf is hurting her own credibility by reposting the opening paragraphs of sciencey promotional PR articles instead of reading the actual article first. We need experts to reduce the amount of misinformation clogging the internet, not increase it.


[1]        Molet J, Heins K, Zhuo X, et al. Fragmentation and high entropy of neonatal experience predict adolescent emotional outcome. Translational psychiatry 2016;6:e702.

Dr Caroline Leaf and dualism revisited

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Are we a body with a mind, or a mind with a body?

This may sound like a chicken-and-egg type of conundrum, but it’s a deep philosophical question. The concept of the separation of the mind from the body is known as dualism, and has been debated for centuries because the answer to that question then guides a lot of other philosophies and theories.

Dr Caroline Leaf is a communication pathologist and a self-titled cognitive neuroscientist. She believes that the body and brain are separate from the mind, which significantly influences her teaching. Take, for example, her social media meme-of-the-day today. She posted that, “The brain does not change itself… our MIND changes the brain”. If one assumes that the mind is separate from our brain, then its plausible that the mind influences the brain.

Except that it doesn’t. Our mind is a product of our brain, not a separate entity. Neurological damage from injuries or tumours, electrical stimulation of the brain in the lab, the effect of illicit drugs on the brain like LSD or marijuana, and everyday examples like the changes to our thinking under the influence of caffeine or alcohol, all prove that changes to the structure and function of the brain change thought patterns. It isn’t the other way around. Every brain changes itself too – the brain of an embryo or foetus undergoes massive changes but foetuses don’t have streams of conscious thought. Dr Leaf’s meme is scientifically misguided.

Perhaps what is more worrying is Dr Leaf’s use of scripture to try and justify her view that the mind and the brain are separate. To introduce her meme, Dr Leaf wrote, “Read Luke 16:19-31 to see that the mind is separate from the brain – this is God’s divine design.”

There are a number of scriptures that theologians use to discuss the biblical basis for the separation of the body and soul, but Luke 16:19-31 isn’t one of them. That passage is the parable of Lazarus and the rich man.

It says:

‘There was a rich man who was dressed in purple and fine linen and lived in luxury every day. At his gate was laid a beggar named Lazarus, covered with sores and longing to eat what fell from the rich man’s table. Even the dogs came and licked his sores.
‘The time came when the beggar died and the angels carried him to Abraham’s side. The rich man also died and was buried. In Hades, where he was in torment, he looked up and saw Abraham far away, with Lazarus by his side. So he called to him, “Father Abraham, have pity on me and send Lazarus to dip the tip of his finger in water and cool my tongue, because I am in agony in this fire.”
‘But Abraham replied, “Son, remember that in your lifetime you received your good things, while Lazarus received bad things, but now he is comforted here and you are in agony. And besides all this, between us and you a great chasm has been set in place, so that those who want to go from here to you cannot, nor can anyone cross over from there to us.”
‘He answered, “Then I beg you, father, send Lazarus to my family, for I have five brothers. Let him warn them, so that they will not also come to this place of torment.”
‘Abraham replied, “They have Moses and the Prophets; let them listen to them.”
‘“No, father Abraham,” he said, “but if someone from the dead goes to them, they will repent.”
‘He said to him, “If they do not listen to Moses and the Prophets, they will not be convinced even if someone rises from the dead.”’ (Luke 16:19-31, NIV)

I’m not sure exactly where the convincing proof of the separation of our mind and our body is found in this passage. This is a description of the afterlife, and in this parable, the rich man was very specific about memories (“I have five brothers …”) as well as physical sensations (“I am in agony in this fire”) and even parts of the body (Lazarus’s finger, his tongue). Jesus isn’t telling a story of how the mind is separate to the body, but of a different dimension in which the body and the mind are still together. This passage isn’t proof for the concept of dualism, but against it.

Dualism also has a number of fatal scientific and philosophical flaws, in particular that dualism is conceptually fuzzy, experimentally irrefutable, considers only the adult mind, and violates physics, in particular the law of conservation of energy.

So Dr Leaf bases her teaching on a scientifically and philosophically untenable concept and then attempts to use a scripture which refutes dualism in her attempt to support it. That’s audacious, but then to claim that it’s God’s divine design is, at best, a little brazen.

Dualism may be one of her fundamental philosophies, but I think Dr Leaf should review the basis for it, and possibly reconsider her reliance on it.

For a more in-depth discussion on Dr Leaf and dualism, please see my essay: Dr Caroline Leaf, Dualism, and the Triune Being Hypothesis

Dr Caroline Leaf and the mistruth done three ways.

“Every thought you think impacts every one of the 75-100 trillion cells in your body at quantum speeds!” – Dr Caroline Leaf

I was going to stick to my series on thoughts over the next few days, but Dr Leafs social media gem today was so farcical and fanciful, I had to briefly comment on it.

Dr Caroline Leaf is a communication pathologist and self-titled cognitive neuroscientist. She is ‘flexible’ with the truth when she blogs or posts on social media. It’s never really quite clear exactly where the facts end and the generous ‘poetic licence’ begins. Of course, she never references any of her posts, so it’s anyone’s guess as to how she arrived at the statement in the first place.

Today’s offering is a typical example. It’s a breathless melding of some exaggerated statements, impressive sounding numbers, and a brief reference to a science which sounds catchy but that not even physicists fully understand. It is a master class in taking a concept that’s scientifically incorrect and making it sound like a Nobel Prize winning idea.

Lets breaking it down into its different components and analyse their validity separately:
“Every thought you think impacts … every cell in your body …”
“… every one of the 75-100 trillion cells in your body …”
“… at quantum speeds!”

  1. “Every thought you think impacts … every cell in your body …”

This is the core part of Dr Leaf’s statement. Like most of Dr Leaf’s teaching on our thoughts, her definition of thoughts is incorrect, as is the place of thoughts in the neuro-informational processing schema. Our streams of thought are just slivers of information projected from the deeper regions of the brain into to a wider area of our cerebral cortex. The brain uses this process to analyse the information to a higher degree before acting on it or sending it into memory.

Our thoughts are nothing special. They’re just a small cog in a much larger machine. They do not have any influence beyond what the rest of the brain would allow [1].

Thoughts certainly don’t influence every cell in our body. They physically can’t. Cells are not connected to every other cell in the body

Even if they were connected, it doesn’t make sense that our thoughts influence every other cell. The hyperbole verges on the ridiculous. As if a random fibroblast in the tip of my 5th pinkie toe was significantly influenced by the thought that I had when I felt like chicken for dinner. Dr Leaf’s assertion that, “Every thought you think impacts … every cell in your body”, is a nonsense statement.

  1. “… every one of the 75-100 trillion cells in your body …”

How many cells do you really have in your body? I’ve never really tried to count them all myself, but according to the Smithsonian in Washington, USA, there are only 37.2 trillion (http://www.smithsonianmag.com/smart-news/there-are-372-trillion-cells-in-your-body-4941473/?no-ist). The fact that Dr Leaf has so badly estimated, when all she needed to do was a one line Google search, suggests that she just made the number up. Out of respect to Dr Leaf, she really needs to reference her facts or she will continue to lose credibility,

  1. “… at quantum speeds.”

Quantum physics remains largely mysterious even to those physicists who study it. So it’s a brave person who invokes the “quantum” word in any statement.

It appears that most scientists believe that the maximum quantum speed is the speed of light (http://www.wired.com/2012/01/quantum-information-speed/) so Dr Leaf believes that thought works at light speed. Interesting, because any communication between distant cells in the body is done through electrical transmission or signalling via hormones, which is certainly not at light speeds.

So thought doesn’t talk to our 37.2 trillion cells or even significantly impact them. It can’t. Thought doesn’t control our physiology or our actions, and our body does not work at light speed.

Dr Leaf seems to be largely basing her statement on theory that she has derived from a paper called “Local and nonlocal effects of coherent heart frequencies on conformational changes of DNA”, which suggested that deep love meditation changed some DNA’s ability to wind and unwind. They suggest that the same meditation can change DNA from 3 miles away. Except … that study is deeply flawed.   (see my blog on the subject )

So ultimately, Dr Leaf has just published a social media post which has no scientific basis whatsoever. I would suggest that her followers deserve something better than some flighty, exaggerated puff-piece.


  1. Pitt, C.E., Hold That Thought: Reappraising the work of Dr Caroline Leaf, 2014 Pitt Medical Trust, Brisbane, Australia, URL http://www.smashwords.com/books/view/466848

Dr Caroline Leaf and the brain control misstatement

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“Always give credit where credit’s due.”

Dr Leaf is a communication pathologist, and a self-titled cognitive neuroscientist. Yesterday, Dr Leaf made a couple of carefully worded statements on her social media feeds, which given the quality of her previous couple of neuroscience-based factoids, is a definite improvement.

First, she said that, “Your brain is being continuously rewired throughout your life …”. Yep, I can’t disagree with that one. The brain is a very dynamic tissue, constantly remodelling the synaptic wiring to process the information it receives on a daily basis. That’s why the brain is referred to as ‘plastic’, reflecting the property of plastic to be moulded into any shape.

Her next offering sounds really good too. It’s full of encouragement, positivity and hope … the classic feel-good quote: “You can bring your brain under your control, on the path to a better, healthier, stronger, safer and happier life.” Whether it’s true or not depends on how literally you interpret it.

If you loosely interpret it, then it sounds ok. Sure, we have some control over how we act, and if we live our life in the direction dictated by our values, then we will have a better, healthier, stronger, safer and happier life. Modern psychological theory and therapies confirm this [1].

However, what Dr Leaf actually said was, “You can bring your brain under your control”. Having some control over our actions is entirely different to bringing our brain under our control. We can control some of our actions, but we don’t control our brain any more than we ‘control’ our car.

When we say that we’re ‘controlling’ the car, what we actually mean is that we are controlling the speed and direction of the car. But there are thousands of electrical and mechanical actions that take place each second that are vital for the running of the car, and that we have absolutely no direct control over. It just takes one loose nut or faulty fuse to make the car steer wildly out of control, or stop functioning entirely, and then we’re not in control at all.

In the same way, various diseases or lesions in the brain show that brain is really in control, tic disorders for example. These can range from simple motor tics (sudden involuntary movements) to complex tic disorders, such as Tourette’s (best known for the involuntary tendencies to utter obscenities). Another common example are parasomnias – a group of disorders in which people perform complex behaviours during their sleep – sleep talking, sleep walking, or sleep eating.

The fact we don’t see all of the underlying processes in a fully functional brain simply provides the illusion of control. Our brain is driving, our stream of thought just steers it a little, but it doesn’t take much to upset that veneer of control we think we possess.

Ultimately, our brain is still responsible for our action. We don’t have a separate soul that is able to control our brain. Any decisions that we make are the result of our brain deciding on the most appropriate course of action and enacting it [2] (and see also ‘Dr Caroline Leaf, Dualism, and the Triune Being Hypothesis‘ for a more in-depth discussion on the subject of dualism). Therefore, we can’t ever bring our brain under control.

This is important because if we believe that we can bring our brain under control, then by simple logical extension, we can control everything our brain is responsible for – our emotions, our feelings, our thoughts, our memory, and every single action we make. This is Dr Leaf’s ultimate guiding philosophy, though it’s not how our neurobiology works. If we were to believe that we control our thoughts and feelings, we set up an unwinnable struggle against our very nature, like trying to fight the tides.

We are not in control of all our thoughts, feelings, emotions or all of our actions, and neither do we have to be. We just need to make room for our uncomfortable emotions, feelings and thoughts, and to move in the direction of those things we value.

So if you were to take Dr Leaf at her word, she still missed the mark with her post. It sounds ok in a very general sense, but closer inspection reveals a subtle but significant error.

Giving credit where credit’s due, Dr Leaf has tried to tighten up her social media statements. It’s commendable, but unfortunately she needs to bring her underlying philosophy closer to the accepted scientific position to further improve the quality of her teaching.


  1. Harris, R., Embracing Your Demons: an Overview of Acceptance and Commitment Therapy. Psychotherapy In Australia, 2006. 12(6): 1-8 http://www.actmindfully.com.au/upimages/Dr_Russ_Harris_-_A_Non-technical_Overview_of_ACT.pdf
  2. Haggard, P., Human volition: towards a neuroscience of will. Nat Rev Neurosci, 2008. 9(12): 934-46 doi: 10.1038/nrn2497

Dr Caroline Leaf and the Mixed Message Memes

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If you were talking to your doctor, and she said, “Smoking is bad for you”, while lighting a cigarette for herself, would you be confused? Bit of a mixed message, don’t you think?

When I got back to Facebook last night, I found this interesting post from Dr Leaf: “If you have just spoken or done something … It means you have the physical root thought in your brain.” Perhaps not interesting in an I-never-knew-that sort of way … more interesting in a yet-another-mixed-message sort of way.

Dr Caroline Leaf is a Communication Pathologist and a self-titled Cognitive Neuroscientist. She has a habit of posting fluffy pseudoscientific memes to her social media feeds, which sound plausible at face value, but look a little closer, and they crumble like a sand castle at high tide.

Her current post is actually a bit sturdier than usual. We do use information we’ve learned to guide our ultimate behaviour, which include our words and our actions. But that’s not the whole story.

Our brain is an amazing organ. It processes a torrent of incoming information, compares it to previous experience stored in memory, and then delivers real-time instructions to the rest of the body, whilst updating the memory systems with the new information received. However, the brain also has a limited amount of energy that it can utilise – the brain only runs on about 40 watts of power [1: p7] (the same as a low power light bulb). In order to use this limited energy efficiently, the brain automates certain actions, like skills or habits, while retaining the flexibility to handle situations or to perform different actions than the skills or habits that we have developed.

The brain achieves this feat of brilliance by having a number of different types of memory [2] – procedural memory, priming, classical conditioning and non-associative learning make up implicit memory (memory not available to conscious awareness). Declarative memory is the fifth type of memory, which has two sub-components: episodic memory, which is the recallable memory of specific events (that you had coffee and eggs for breakfast), which itself is heavily dependent on semantic memory, the recallable memory for concepts (the abstract concepts of coffee, eggs, and breakfast) [3].

The storage of memories within declarative memory is also done piecemeal, by breaking down the information stored into chunks. Byrne notes, “We like to think that memory is similar to taking a photograph and placing that photograph into a filing cabinet drawer to be withdrawn later (recalled) as the ‘memory’ exactly the way it was placed there originally (stored). But memory is more like taking a picture and tearing it up into small pieces and putting the pieces in different drawers. The memory is then recalled by reconstructing the memory from the individual fragments of the memory.” [4] Retrieving the original memory is an inaccurate process, because sometimes pieces of the memory are lost, faded or mixed up with another [5]. What the memory systems lose in accuracy of recall is more than made up for by the flexibility of the information stored in memory to plan current action, and to imagine possible future scenarios.

Each time the brain decides on an action, it subconsciously performs five different steps to determine the best action to take, although the best way to consider the process is simply to say that “voluntary” action is a flexible and intelligent interaction with the subject’s current and historical context (present situation and past experience) [6].

In a new situation, the brain takes the information from the senses (sight, hearing etc) and compares it with the necessary pieces of information recalled from memory, including previous actions taken in similar situations and their outcome. It then decides on the best course of action, plans what to move, when to move, how to move, and then performs one more final check before proceeding. If the situation is familiar, and the brain has a previous script to follow, like a skill or a habit, it will perform those actions preferentially because it’s more efficient in terms of brain energy used, but if there is no previous script, the brain will plan a novel set of actions appropriate to the situation.

The best example of this is driving a car. I learnt to drive in my parents’ 1970-something, 4-to-the-floor Chrysler Galant. The skills required to handle a manual transmission car with an old clutch was challenging to learn, but once those skills were mastered and road rules learnt, I could drive successfully. But I didn’t need to learn evasive maneuvers. When confronted with an emergency situation for the first time, my brain moved my body very quickly to control the car in ways I’d not practiced, before my conscious mind had a chance to process the incident. So my brain used skills I had learnt in ways that I had not learnt, independent of my conscious will.

Dr Leaf’s underlying assumption is that we are in full control of our thoughts and actions. Unfortunately for Dr Leaf, neuroscience proves that predictable brain activity occurs several seconds before a person is aware of their intention to act [7, 8], which runs counter to her presupposition. To try and patch the enormous hole in her argument, she contends that the brain activity that occurs before we are consciously aware of our intentions is just our non-conscious brain accessing our stored, previously conscious thoughts (see also [9], page 42). The implication is that anything you do is still a choice that you made in either the present, or your past. As she said in the Facebook post, “Everything you say and do is first a thought that you have built in your brain.”

Unfortunately for Dr Leaf, cognitive neuroscience disproves her folk-science. It’s way oversimplified to suggest that everything we do is based on our thought life. There are many chunks of our memory that don’t come from a willful, conscious input of information (acquired fear is one example). And the brain can use chunks of memory, often from memory systems not accessible by our conscious awareness, to produce complex actions that are completely new, without needing our conscious input.

Even though cognitive neuroscience disproves her meme, which is embarrassing enough for a woman who calls herself a cognitive neuroscientist, the bigger problem for this meme is that Dr Leaf is again contradicting herself.

About a month ago, Dr Leaf published on her social media feeds, “Don’t blame your physical brain for your decisions and actions. You control your brain!” Now she says that your words and actions are the result of a hardwired “physical root thought”, so your decisions and actions ARE the result of your physical brain. Which is it Dr Leaf? For the sake of her followers, her clarification would be welcome. After all, the more she contradicts herself, the more doubt she casts over the validity of the rest of her writing and teaching. Is she accurately interpreting research, and drawing valid conclusions? Dr Leaf is welcome to comment.

But one thing’s for sure; her mixed message memes are certainly not doing her any favours.


  1. Berns, G., Iconoclast : a neuroscientist reveals how to think differently. 2008, Harvard Business School Press, Boston:
  2. Squire, L.R. and Zola, S.M., Structure and function of declarative and nondeclarative memory systems. Proceedings of the National Academy of Sciences, 1996. 93(24): 13515-22 http://www.pnas.org/content/93/24/13515.abstract
  3. Binder, J.R. and Desai, R.H., The neurobiology of semantic memory. Trends Cogn Sci, 2011. 15(11): 527-36 doi: 10.1016/j.tics.2011.10.001
  4. Byrne, J.H. Learning and Memory (Section 4, Chapter 7). Neuroscience Online – an electronic textbook for the neurosciences 2013 [cited 2014, Jan 3]; Available from: http://neuroscience.uth.tmc.edu/s4/chapter07.html.
  5. Bonn, G.B., Re-conceptualizing free will for the 21st century: acting independently with a limited role for consciousness. Front Psychol, 2013. 4: 920 doi: 10.3389/fpsyg.2013.00920
  6. Haggard, P., Human volition: towards a neuroscience of will. Nat Rev Neurosci, 2008. 9(12): 934-46 doi: 10.1038/nrn2497
  7. Libet, B., et al., Time of conscious intention to act in relation to onset of cerebral activity (readiness-potential). The unconscious initiation of a freely voluntary act. Brain, 1983. 106 (Pt 3): 623-42 http://www.ncbi.nlm.nih.gov/pubmed/6640273
  8. Soon, C.S., et al., Unconscious determinants of free decisions in the human brain. Nat Neurosci, 2008. 11(5): 543-5 doi: 10.1038/nn.2112
  9. Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:

(PS: And happy Independence Day, USA! #4thofjuly )