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 )

Dr Caroline Leaf and the Myth of the Blameless Brain

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When I came back to Facebook this morning, I found this from Dr Leaf on my feed,

“Don’t blame your physical brain for your decisions and actions. You control your brain!”

Dr Caroline Leaf is a Communication Pathologist and a self-titled Cognitive Neuroscientist. Her post follows her theme of the last couple of weeks, the premise that the mind is the dominant cognitive force, controlling the physical brain, and indeed, all matter. I have written about the Myth of Mind Domination in a previous blog. But Dr Leaf’s latest offering here deserves special attention.

Lets think about her statement in more detail:

“Don’t blame your physical brain for your decisions and actions.”

What Dr Leaf is really saying is that the physical brain has no role in your choices or behaviour whatsoever, because if your physical brain had a role in the decisions and actions you make, it would also carry some blame for your poor decisions and actions.

“You control your brain.”

The question to ask here is, “Which part of ‘you’ controls your brain?” Her answer would be, “Your mind”, although she never says where the mind is. Certainly not in the physical brain or even in our physical body, since “Our mind is designed to control the body, of which the brain is a part, not the other way around.” [1: p33].

So an ethereal, disembodied force is in full control of our physical body, such that our brain has no role in the decisions we make or actions we take. Even at this stage of analysis, Dr Leaf’s statement is ludicrous. But wait, there’s more.

Dr Leaf’s statement puts her at odds with real Cognitive Neuroscientists. Professor Patrick Haggard is the Deputy Director of the Institute of Cognitive Neuroscience at the University College London. He has authored or co-authored over 350 peer-reviewed articles on the neuroscience of making choices. He writes, “Modern neuroscience rejects the traditional dualist view of volition as a causal chain from the conscious mind or ‘soul’ to the brain and body. Rather, volition involves brain networks making a series of complex, open decisions between alternative actions.” [2] Strike one for Dr Leaf.

Dr Leaf’s statement puts her at odds with herself. Two weeks ago when misinterpreting James 1:21, Dr Leaf wrote, “How you react to events and circumstances of your life is based upon your perceptions.” Perception is classically defined in neurobiology as conscious sensory experience [3: p8] although the work of cognitive neuroscientists has shown that perception can also be non-conscious [4, 5]. Either way, perception is based entirely on processing within the brain [3: p6-11]. So one week, Dr Leaf is saying that our brain determines how we behave, and then ten days later, she is telling us that our brain does not determine how we behave. Which is it? Strike two for Dr Leaf.

Finally, Dr Leaf’s statement is borderline insulting to the sufferers of congenital or acquired brain disorders. Would you tell a stroke patient that they shouldn’t blame their physical brain for their immobility, because they’re mind is in control of their brain? What about a child with Cerebral Palsy? Would you tell a mother of a child with Downs Syndrome that their child is having recurrent seizures because they aren’t using their mind properly to control their brain? Dr Leaf is doing exactly that. I find it incredible that she could be so insensitive, given her background as a speech pathologist working with patients with Acquired Brain Injury.

I imagine that her defence would be something along the lines of, “What I meant was, ‘don’t blame your normal physical brain for your decisions and actions. You control your functional brain.’” That sort of explanation would be less insulting to people with strokes or brain injuries, but it then undermines her whole premise. The hierarchy of the brain and the mind doesn’t change just because a part of the brain is damaged.

Besides, changes to brain function at any level can change the way a person thinks and behaves. The classic example was Phineas Gage, who in 1848, accidentally blasted an iron rod through his skull, damaging his left frontal lobe. History records that Gage’s well-mannered, pleasant demeanour changed suddenly into a fitful, irreverent, obstinate and capricious man whose workmates could no longer stand him [6]. Medical science has documented numerous cases of damage to the right ventromedial prefrontal cortex causing acquired sociopathy [7]. How can the mind be in control of the brain when an injury to the brain causes a sudden change in thought pattern and behaviour? Clearly one CAN blame the physical brain for one’s decisions and actions. Strike three. You’re out.

Dr Leaf is welcome to comment here. Perhaps she meant something completely different by her post, although there’s only so many ways that such a statement can be interpreted.

Ultimately, Dr Leaf’s love of posting pithy memes of dubious quality is now getting embarrassing. Being so far behind the knowledge of a subject in which she claims expertise is ignominious. Undermining her own premise and contradicting herself is just plain embarrassing. But to be so insensitive to some of the most vulnerable is poor form. I think she’d be well served by re-examining her facts and adjusting her teaching.


  1. Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:
  2. Haggard, P., Human volition: towards a neuroscience of will. Nat Rev Neurosci, 2008. 9(12): 934-46 doi: 10.1038/nrn2497
  3. Goldstein, E.B., Sensation and perception. 8th ed. 2010, Wadsworth, Cengage Learning, Belmont, CA:
  4. Kouider, S. and Dehaene, S., Levels of processing during non-conscious perception: a critical review of visual masking. Philos Trans R Soc Lond B Biol Sci, 2007. 362(1481): 857-75 doi: 10.1098/rstb.2007.2093
  5. Tamietto, M. and de Gelder, B., Neural bases of the non-conscious perception of emotional signals. Nat Rev Neurosci, 2010. 11(10): 697-709 doi: 10.1038/nrn2889
  6. Fumagalli, M. and Priori, A., Functional and clinical neuroanatomy of morality. Brain, 2012. 135(Pt 7): 2006-21 doi: 10.1093/brain/awr334
  7. Mendez, M.F., The neurobiology of moral behavior: review and neuropsychiatric implications. CNS Spectr, 2009. 14(11): 608-20 http://www.ncbi.nlm.nih.gov/pubmed/20173686


Dr Caroline Leaf and the Brain Changes Meme

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I swore on the Bible once.

One of my patients needed my testimony in a court case, and when I went to the lawyer’s offices to supply my statement, before they accepted it as official testimony, they asked me to swear on their Bible.  I’m not sure if the surprise I felt showed on my face.  I wasn’t expecting it, that’s for sure, since the only time I have seen people swear on the Bible was in cheesy American TV courtroom dramas.

It was a simple, but oddly surreal moment.  I placed my hand on the Bible and said, “I solemnly swear that I will tell the truth, the whole truth and nothing but the truth.”

We have heard it said so many times that we become blasé to the importance of those words.  But the truth is only true if it is, ”the whole truth and nothing but the truth”.

When Dr Leaf published her latest meme this morning, she was telling the truth.  She said via social media,

“Your brain changes as a result of your decisions.”

Dr Caroline Leaf is a Communication Pathologist and self-titled Cognitive Neuroscientist.  The on-going theme of her recent social media offerings is the “Mind over matter” meme: essentially our mind leads and our brain follows.  This was a fundamental argument in her most recent book too (see reference [1], pages 33 and 38).

The main problem for Dr Leaf is that real cognitive neuroscientists disagree, like Haggard,

“Modern neuroscience rejects the traditional dualist view of volition as a causal chain from the conscious mind or ‘soul’ to the brain and body.  Rather, volition involves brain networks making a series of complex, open decisions between alternative actions.” [2]

But didn’t I say in the beginning of this blog that Dr Leaf was telling the truth?  Yes, I did say that.  And she is telling the truth … she’s just not telling the whole truth.

It’s true that our brains change as a result of our decisions.  But the brain changes as a result of hundreds of different inputs and signals.  Our brain is constantly changing – growing new branches and pruning others.  Most of these changes occur subconsciously.  Only the tiniest fraction would be due to our conscious decision-making.  The true limiting factor of our brains ability to change is genetics, specifically the genes that code for the proteins that are integral to the nerve cells ability to grow the branches it needs to make the right connections.

So while it’s not technically untrue, if you take Dr Leaf’s meme at face value, you would get the impression that the mind controls the brain, which was her intention.

In actual fact, our psychology is dependent on our biology, and the brain is in control of the mind, not the other way around.


1.         Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:
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 on James 1:21 – Redux

So, we’ve all heard the saying, “If at first you don’t succeed, try and try again.”  Dr Leaf has certainly done that.

Dr Caroline Leaf is a Communication Pathologist and self-titled Cognitive Neuroscientist.  Not content to completely misinterpret James 1:21 only once, she posted on social media today, “James 1:21.  Our thoughts and perceptions have a direct and overwhelmingly significant effect on the cells of our body.”

If for nothing else, Dr Leaf at least gets points for persistence.  A week and a half ago, Dr Leaf again used James 1:21 to attempt to justify a meme on perception.  I’d love to know what version of the Bible that she’s using, because it seems that in her Bible, James 1:21 can be interpreted any way that one wants.

Lets recap: James 1:21 says,

“Wherefore lay apart all filthiness and superfluity of naughtiness, and receive with meekness the engrafted word, which is able to save your souls.” (KJV)

There are too many big words there for my liking, so I went through an on-line, widely used Greek lexicon, to look at the meanings of the words.  Then I translated them into something more understandable, to make sure that I didn’t miss the bit about perception.

Using the Strong’s dictionary and concordance built in to the Blue Letter Bible site (http://www.blueletterbible.org/Bible.cfm?b=Jas&c=1&v=21&t=KJV#s=1147021) I was able to translate the original Greek into something more manageable.

“Therefore shed all the morally defiling wickedness and excess malice, and, with meekness, embrace the teaching that is implanted by your mentors, which has the power to rescue your eternal soul.”

Wait … where did James talk about perception, and how our cells react to our thoughts?  Reviewing the scripture and its translation the second time around didn’t change anything, because there is nothing in James 1:21 that is in any way remotely connected to perception, thinking and our cells biological functioning.

Scripture is the inspired word of God, and “is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work.” (2 Tim 3:16-17, NIV)  What James is writing about is essential, and Christians need to embrace what he was teaching.

Which is why it is so important for Dr Leaf to interpret scripture correctly.  For the second time in two weeks, Dr Leaf has completely misapplied a scripture to one of her memes.  As if that isn’t concerning enough for a woman than regularly interprets scripture to audiences in the thousands every week, there isn’t any scientific evidence to back up her claim either.  As I have written about before, there is no evidence that the mind controls the brain.  Rather, our psychology is dependant on our biology.  More on this in future posts.  But the onus is on Dr Leaf to provide evidence to back up her claim.  I encourage her to publish specific evidence that she believes justifies her claims that our thoughts alter our cellular biology.

Otherwise, I think another popular phrase would better apply: “Quit while you’re ahead”.

UPDATE (17/6/2014)

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I was reviewing Dr Leaf’s posts tonight, and I came across this response that Dr Leaf posted on the 5th of June.  Clearly I wasn’t the only person who wondered exactly how James 1:21 applied to her meme.

Dr Leaf’s explained: “By ‘implanting the word of God your soul will be saved’ (James 1:21) – so by memorizing God’s Word we build healthy thoughts into our brain that improve the health of our cells.”

I’m sure that Dr Leaf thought she was climbing out of a hole, although I think she’s only dug herself deeper.

Firstly, while I’m not a trained theologian, I can read.  Dr Leaf reinterprets this long-suffering scripture again, “By ‘implanting the word of God your soul will be saved’.”  But that’s not what it says at all.  From the KJV which I originally quoted: ” … receive with meekness the engrafted word, which is able to save your souls.” (Emphasis added)  It’s a subtle but important difference.  My understanding is that salvation comes confession and repentance (Romans 10:9-10, 2 Corinthians 7:10).  The word of God is able to save souls, but as the Parable of the Sower (Luke 8:4-15) shows, it doesn’t always bear fruit.  Satan himself knows the Bible inside out, but he certainly isn’t saved.  Perhaps someone who is theologically trained can confirm the points here.  I’d certainly appreciate it.  But for now, I propose that Dr Leaf has misinterpreted this scripture again.

Dr Leaf goes on to claim that by memorizing scripture, “we build healthy thoughts in our brain that improve the health of our cells.”  Dr Leaf is really grasping at straws here.  The “soul” that James is referring to is psyche in the Greek, translated as “the seat of the feelings, desires, affections, aversions (our heart, soul etc.); the (human) soul in so far as it is constituted that by the right use of the aids offered it by God it can attain its highest end and secure eternal blessedness, the soul regarded as a moral being designed for everlasting life; the soul as an essence which differs from the body and is not dissolved by death (distinguished from other parts of the body)”. (http://www.blueletterbible.org/lang/lexicon/lexicon.cfm?Strongs=G5590&t=KJV)  So the word that James used has nothing to do with the body.

Dr Leaf has to apply her own set of assumptions to the scripture, that a saved soul must be healthy thoughts, and that healthy thoughts leads to healthy cells.  Its a myth that healthy thoughts lead to healthy cells (more on this in a future post).  To suggest that salvation and healthy thoughts are one and the same is also an assumption on Dr Leaf’s part, which I don’t think the scripture supports in any way.

So in short, Dr Leaf’s explanation really hasn’t helped her cause.  Her meme is still scripturally and scientifically baseless.

Dr Caroline Leaf and the Sound Mind Meme

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Caroline Leaf is a brave woman.

Dr Caroline Leaf is a Communication Pathologist and self-titled Cognitive Neuroscientist.  She regularly publishes memes on her social media sites like FaceBook and Instagram that are supposed to reinforce her main teaching.

Her recent post declared:

“Your mind is all-powerful.  Your brain simply captures what your mind dictates. 2 Timothy 1:7”

We’re supposed to smile and nod, and accept that it must be right on face value alone.  Like, “Trust me, I’m a cognitive neuroscientist”.

But if we peel away the thin veneer of trust that covers the surface of this meme, we see that there isn’t much in the way of substance that supports it.

For a start, the only reference that Dr Leaf supplies is the scripture from 2 Timothy 1:7. She’s used this scripture in her work before, stating in her 2013 book, “For now, rest in the assurance that what God has empowered you to do with your mind is more powerful and effective than any medication, any threat, any sickness, or any neurological challenge.  The scripture is clear on this: You do not have a spirit of fear but of love, power and a sound mind (2 Tim 1:7).” [1]

So, first things first: the scripture 2 Timothy 1:7 says: “For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind.”  (KJV)  But what does it actually mean?

Studying the full context and the original Greek reveals that this verse is not a reference to our mental health, but to the courage to perform the work that God has given us.

The Greek word for “fear” in this scripture refers to “timidity, fearfulness, cowardice”, not to anxiety or terror.  The Greek word that was translated “of a sound mind” refers to “self-control, moderation”, not to serenity.  So Paul is telling Timothy that God doesn’t make him timid, but full of power, love and self-control.  Paul teaches that through the Holy Spirit, we have all the tools: power, love and the control to use them, so we don’t have to be afraid.

In addition, looking at the verse in its context, and in a different translation, shows it in a completely different light to the way Dr Leaf promotes it.  From the NIV, “I am reminded of your sincere faith, which first lived in your grandmother Lois and in your mother Eunice and, I am persuaded, now lives in you also.  For this reason I remind you to fan into flame the gift of God, which is in you through the laying on of my hands. For the Spirit God gave us does not make us timid, but gives us power, love and self-discipline. So do not be ashamed of the testimony about our Lord or of me his prisoner. Rather, join with me in suffering for the gospel, by the power of God.” (2 Timothy 1:5-8)

The scripture doesn’t say that our minds are more powerful than medication, sickness or “neurological challenge”.  It clearly doesn’t say that our mind is all-powerful, and that our brains simply capture what our minds dictate.  This scripture doesn’t have anything to do with our mental health (nor is there any scientific evidence to suggest that our mind is all-powerful or that the brain captures what our mind dictates, although that is another blog entirely (see also: Dr Caroline Leaf and the Myth of Mind Domination)).

Scripture is the inspired word of God.  It’s poor form to knowingly misquote someone to support your position, but it’s a very brave person that would misquote scripture for the sake of their argument.  And the inaccuracy of Dr Leaf’s use of both scripture and science surely calls into question the accuracy of all of her other memes.  Perhaps those who follow Dr Leaf’s social media feeds should also start taking them with more than a pinch of salt.


1.         Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:

(New Testament Greek lexicon used for the word search was the Blue Letter Bible Strongs Lexicon, Reference: Greek Lexicon: G1167 (KJV). Retrieved from http://www.blueletterbible.org/lang/lexicon/lexicon.cfm?Strongs=G1167&t=KJV and Greek Lexicon: G4995 (KJV). Retrieved from http://www.blueletterbible.org/lang/lexicon/lexicon.cfm?Strongs=G4995&t=KJV)

Dr Caroline Leaf and the Myth of Mind Domination

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“You control your brain … your brain does not control you!”

So says Dr Caroline Leaf, Communication Pathologist and self-titled Cognitive Neuroscientist.

You’d hope that Dr Leaf would know. She says on her website that “Since the early 1980‘s she has studied and researched the Mind-Brain connection.” And if you take what she says at face value, it sure sounds right. Of course we’re in control. My brain does what I tell it to do. Except that it actually doesn’t. Our brain has a lot more control over us than we realize.

First of all, our “free” will isn’t actually free at all, but constrained by a number of unseen, subconscious processes that are entirely dependent on our brain. It may seem like we’re in complete control of our choices, but our subconscious brain has already done most of the work for us. Even if we had complete freedom over our choices, our “free” will would still require an intact brain in order to carry out its wishes.

The “control” of our brain is very similar to our “control” when we drive a 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. The fact we don’t see all of the underlying processes in a fully functional brain simply provides the illusion of control.

For example, there are a number of lesions of the parietal lobes within the brain that give rise to some unusual but intriguing conditions. One of which is a condition called “Alien Hand Syndrome”. Wegner describes two patients with Alien Hand Syndrome, a lady whose “left hand would tenaciously grope for and grasp any nearby object, pick and pull at her clothes, and even grasp her throat during sleep … She slept with the arm tied to prevent nocturnal misbehavior”, and a man who, “While playing checkers on one occasion, the left hand made a move he did not wish to make, and he corrected the move with the right hand; however, the left hand, to the patient’s frustration, repeated the false move. On other occasions, he turned the pages of the book with one hand while the other tried to close it; he shaved with the right hand while the left one unzipped his jacket” [1]. Alien Hand Syndrome demonstrates that our decision-making and our action sequences are controlled by two separate systems in our brains.

There are other conditions that also show that our brains control us more than we control them. A more common example are the tic disorders, such as simple motor tics (sudden involuntary movements) and complex tic disorders, such as Tourette’s (best known for the involuntary tendencies to utter obscenities). Even more common are parasomnias – a group of disorders in which people perform complex behaviours during their sleep – sleep talking, sleep walking, sleep eating. One of my patients once drove her car while asleep (Honestly, that’s no exaggeration!).

So at best, we only have partial control of our brain. Our brain is driving, our mind just steers it a little, but it doesn’t take much for that veneer of control that we think we possess.

The other way in which we appear to have control over our brain is through free will. Free will has been debated for years on philosophical grounds, but over three decades ago, Libet performed an experiment that demonstrated measurable and predictable brain activity occurring up to a full second before a test subject was consciously aware of the intention to act [2]. More recently, a study by Soon et al showed that predictable brain activity occurred up to eight seconds before a person was aware of their intention to act [3]. As Bonn says, “the gist of these findings is that our feeling of having consciously willed an act is illusory in many ways. It seems that the conscious awareness of intention that we place so much weight upon, that we naively think of as causal, is, in fact, a narrative construction that is formed well after the train of causation has been set in motion.” [4]

The Oracle explained it to Neo, “… you didn’t come here to make the choice. You’ve already made it. You’re here to try to understand why you made it.” (Matrix Reloaded, 2003)

Haggard concludes, “Modern neuroscience rejects the traditional dualist view of volition as a causal chain from the conscious mind or ‘soul’ to the brain and body. Rather, volition involves brain networks making a series of complex, open decisions between alternative actions.” [5]

This does not eliminate our capacity to choose, but frames it in a more realistic fashion. As Bonn points out, “Although we are not consciously aware of what is going on at every stage of the chain of neural events leading to action, there is room for a degree of conscious involvement if only to pull the emergency brake before it is too late. Thus, although it may not be the initial source of motivations and behavioral impulses, the part of the mind that is self-reflective; that can envision the self in causal and narrative contexts, may serve important monitoring and control functions.” [4]

Again, we have less control over our brain than we realize. We feel like we have made a choice, but more often than not, our brain already made the choice for us up to eight seconds beforehand, and the feeling of intention that we have is simply our conscious mind catching up – not making the choice, but finding a reason for why we made the choice.

It’s always nice when people who call themselves neuroscientists tell us what feels intuitively correct. In the cold, hard light of day, actual neuroscientists don’t tell us what’s intuitively correct, but what’s actually correct. It may seem like our mind is in control of our brain, but modern neuroscience confirms that our brain is the dominant force, while our mind just helps to steer a little.


  1. Wegner, D.M., Precis of the illusion of conscious will. Behavioral and Brain Sciences, 2004. 27(5): 649-59
  2. 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
  3. 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
  4. 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
  5. Haggard, P., Human volition: towards a neuroscience of will. Nat Rev Neurosci, 2008. 9(12): 934-46 doi: 10.1038/nrn2497


Dr Caroline Leaf – Contradicted by the latest research

Mr Mac Leaf, the husband of Dr Caroline Leaf, kindly took the time to respond to my series of posts on the teachings of Dr Leaf at Kings Christian Centre, on the Gold Coast, Australia, earlier this month. As I had intended, and as Mr Leaf requested, I published his  reply, complete and unabridged (here).

This blog is my reply.  It is heavily researched and thoroughly referenced.  I think it’s fair to say that while Dr Leaf draws her conclusions from some scientific documents, there is more than enough research that contradicts her statements and opinions.  I have only listed a small fraction, and only on some of the points she raised.

In fairness, the fields of neurology and neuroscience are vast and rapidly expanding, and it is impossible for one person to cover all of the literature on every subject.  This applies to myself and Dr Leaf.  However, I believe that the information I have read, and referenced from the latest peer-reviewed scholarly works, do not support Dr Leaf’s fundamental premises.  If I am correct, then the strength and validity of Dr Leaf’s published works should be called into question.

As before, I welcome any reply or rebuttal that Dr Leaf wishes to make, which I will publish in full if she requests.  In the interests of healthy public debate, and encouraging people to make their own informed decisions on the teachings of Dr Leaf, any comments regarding the response of Mr Leaf, Dr Leaf or myself, are welcome provided they are constructive.

This is a bit of a lengthy read, but I hope it is worthwhile.

Dear Mr Leaf,

Thank you very much for taking the time out to reply to some of the points raised in my blog.  I am more than happy to publish your response, and to publish any response you wish to make public.


I published my blog posts to open up discussion on the statements made by Dr Leaf at the two meetings that I attended at Kings Christian Centre on the Gold Coast.  As you rightly point out, people should be able to make informed decisions.  A robust discussion provides the information required for people to make an informed choice.  Any contributions to this discussion from either yourself or Dr Leaf would be most welcome.

I apologise if you interpreted my blogs as judgemental, or if you believe there are any misunderstandings.  You may or may not have read my final two paragraphs from the third post, in which I acknowledged that I may have misunderstood where she was coming from, but that I would welcome her response.  If there were any misunderstandings, it is likely because Dr Leaf did not make any attempt to reference any of the statements she made on the day.  You may argue that she was speaking to a lay audience, and referencing is therefore not necessary.  However, I have been to many workshops for the lay public by university professors, who have extensively referenced their information during their presentations.  A lay audience does not preclude providing references.  Rather, it augments the speakers authority and demonstrates the depth of their knowledge on the subject at hand.


It’s interesting that you feel the need to resort to defence by association, and Ad Hominem dismissal as your primary counter to the points I raised.

Can you clarify how attending the same university as Dr Christaan Barnard, or a Nobel laureate, endorses her arguments or precludes her from criticism?  I attended the University of Queensland where Professor Ian Frazer was based.  He developed the Human Papilloma Virus vaccine and was the 2006 Australian of the Year.  Does that association enhance my argument?

Can you also clarify why a reference from a colleague was preferred to letting Dr Leaf’s statements and conclusions speak for themselves?  Dr Amua-Quarshie’s CV is certainly very impressive, no doubt about that, although he doesn’t list the papers he’s published.  (I’m assuming that to hold the title of Adjunct Professor, he’s published peer-reviewed articles.  Is he willing to list them, for the record?)

Whatever his credentials, his endorsement means very little, since both Dr Leaf and Dr Amua-Quarshie would know from their experience in research that expert opinion is one of the lowest forms of evidence, second worst only to testimonials [1].  Further, both he and Dr Leaf are obviously close friends which introduces possible bias.  His endorsement is noteworthy, but it can not validate every statement made by Dr Leaf.  Her statements should stand up on their own through the rigors of critical analysis.

On the subject of evidence, disparaging your critics is not a substitute for answering their criticism.  Your statement, “By your comments it is obvious that you have not kept up to date with the latest Scientific research” is an assumption that is somewhat arrogant, and ironic since Dr Leaf is content to use superseded references dating back to 1979 to justify her current hypotheses.


In the blog to which you referred, Dr Leaf makes a number of statements that are intended to support her case.  These include the following.

“A study by the American Medical Association found that stress is a factor in 75% of all illnesses and diseases that people suffer from today.”  She fails to reference this study.

“The association between stress and disease is a colossal 85% (Dr Brian Luke Seaward).”   But again, she fails to reference the quote.

“The International Agency for Research on Cancer and the World Health Organization has concluded that 80% of cancers are due to lifestyles and are not genetic, and they say this is a conservative number (Cancer statistics and views of causes Science News Vol.115, No 2 (Jan.13 1979), p.23).”  It’s good that she provides a reference to her statement.  However, referencing a journal on genetics from 1979 is the equivalent of attempting to use the land-speed record from 1979 to justify your current preference of car.  The technology has advanced significantly, and genetic discoveries are lightyears ahead of where they were more than three decades ago.

“According to Dr Bruce Lipton (The Biology of Belief, 2008), gene disorders like Huntington’s chorea, beta thalassemia, cystic fibrosis, to name just a few, affect less than 2% of the population. This means the vast majority of the worlds population come into this world with genes that should enable the to live a happy and healthy life. He says a staggering 98% of diseases are lifestyle choices and therefore, thinking.”  Even if it’s true that Huntingtons, CF etc account for 2% of all illnesses, they account for only a tiny fraction of genetic disease.  And concluding that the remaining 98% must therefore be lifestyle related is overly simplistic.  It ignores the genetic influence on all other diseases, other congenital, and environmental causes of disease.  I will fully outline this point soon.

Similarly, “According to W.C Willett (balancing lifestyle and genomics research for disease prevention Science (296) p 695-698, 2002) only 5% of cancer and cardiovascular patients can attribute their disease to hereditary factors.”  Science is clear that genes play a significant role in the development of cardiovascular disease and most cancers, certainly greater than 5%.  Again, I will discuss this further soon.

“According to the American Institute of health, it has been estimated that 75 – 90% of all visits to primary care physicians are for stress related problems (http://www.stress.org/americas.htm). Some of the latest stress statistics causing illness as a result of toxic thinking can be found at: http://www.naturalwellnesscare.com/stress-statistics.html”  These websites not peer-reviewed, and both suffer from a blatant pro-stress bias.

You’ll also have to forgive my confusion, but Dr Leaf also wrote, “Dr H.F. Nijhout (Metaphors and the Role of Genes and Development, 1990) genes control biology and not the other way around.”  So is she saying that genes DO control development?


Influence Of Thought On Health

Dr Leaf has categorically stated that “75 to 98% of all illnesses are the result of our thought life” on a number of occasions.  She repeated the same statement in her most recent book so it is something she is confident in.  However, in order to be true, this fact must be consistent across the whole of humanity.

And yet, in a recent peer-reviewed publication, Mara et al state, “At any given time close to half of the urban populations of Africa, Asia, and Latin America have a disease associated with poor sanitation, hygiene, and water.” [2]  Bartram and Cairncross write that “While rarely discussed alongside the ‘big three’ attention-seekers of the international public health community—HIV/AIDS, tuberculosis, and malaria—one disease alone kills more young children each year than all three combined. It is diarrhoea, and the key to its control is hygiene, sanitation, and water.” [3]  Hunter et al state that, “diarrhoeal disease is the second most common contributor to the disease burden in developing countries (as measured by disability-adjusted life years [DALYs]), and poor-quality drinking water is an important risk factor for diarrhoea.” [4]

Toilets and clean running water have nothing to do with stress or thought.  We live in a society that essentially prevents more than half of our illnesses because of internal plumbing, with additional benefits from vaccination and population screening.  If thoughts have any effect on our health, they are artificially magnified by our clean water and sewerage systems.  Remove those factors and any effects of thought on our health disappear from significance.  Dr Leaf’s assertion that 75 to 98% of human illness is thought-related is a clear exaggeration.

Let me be clear – I understand the significance of stress on health and the economy, but it is not the cause of 75-98% of all illnesses.  I’m not sure if there is a similar study in the US, but the latest Australian data suggests that all psychological illness only counts for 8% of visits to Australian primary care physicians [5].

In terms of cancer, I don’t have time to exhaustively list every cancer but of the top four listed in the review “Cancer Statistics 2013” [6] , here are the articles that list the gene x environment interactions:

  1. PROSTATE – There are only two risk factors for prostate cancer, familial aggregation and ethnic origin. No dietary or environmental cause has yet been identified [7].  It is most likely caused by multiple genes at various loci [8].
  2. BREAST – Genes make up 25% of the risk factors for breast cancer, and significantly interacted with parity (number of children born) [9].
  3. LUNG/BRONCHUS – Lung cancer is almost exclusively linked to smoking, but nicotine addiction has a strong hereditary link (50-75% genetic susceptibility) [10].
  4. COLORECTUM – Approximately one third of colorectal cancer is genetically linked [11].

So the most common cancer is not linked to any environmental factors at all, and the others have genetic influences of 25% to more than 50%.  This is far from being 2% or 5% as Dr Leaf’s sources state.

Also in terms of heart disease, the INTERHEART trial [12] lists the following as significant risk factors, and I have listed the available gene x environment interaction studies that have been done on these too:

  1. HIGH CHOLESTEROL – Genetic susceptibility accounts for 40-60% of the risk for high cholesterol [13].
  2. DIABETES – Genetic factors account for 88% of the risk for type 1 diabetes [14].  There is a strong genetic component of the risk of type 2 diabetes with 62-70% being attributable to genetics [15, 16].
  3. SMOKING – nicotine addiction has a strong hereditary link (50-75% genetic susceptibility) [10].
  4. HYPERTENSION – While part of a much greater mix of variables, genetics are still thought to contribute between 30% and 50% to the risk of developing high blood pressure [17].

So again, while genes are a part of a complex system, it is clear from the most recent evidence that genetics account for about 50% of the risk for cardiovascular disease, which again is a marked difference between the figures that Dr Leaf is using to base her assertions on.

Atrial Natriuretic Peptide

I am aware of research that’s studied the anxiolytic properties of Atrial Natriuretic Peptide.  For example, Wiedemann et al [18] did a trial using ANP to truncate panic attacks.  However, these experiments were done on only nine subjects, and the panic attacks were induced by cholecystokinin.  As such, the numbers are too small to have any real meaning.  And the settling is completely artificial.  Just as CCK excretion does not cause us all to have panic attacks every time we eat, ANP does not provide anxiolysis in normal day to day situations.  Besides, if ANP were really effective at reducing anxiety, then why do people suffering from congestive cardiac failure, who have supraphysiological levels of circulating ANP [19] , also suffer from a higher rate of anxiety and panic disorders than the general population? [20]

The Heart As A Mini-Brain

As for Heartmath, they advance the notion of the heart being a mini-brain to give themselves credibility.  It’s really no different to an article that I read the other day from a group of gut researchers [21] – “‘The gut is really your second brain,’ Greenblatt said. ‘There are more neurons in the GI tract than anywhere else except the brain.’”  The heart as a mini-brain and the gut as a mini-brain are both figurative expressions.  Neither are meant to be taken literally.  I welcome Dr Leaf to tender any further evidence in support of her claim.

Hard-Wired For Optimism

As for being wired for optimism, the brain is likely pre-wired with a template for all actions and emotions, which is the theory of protoconsciousness [22].  Indeed, neonatal reflexes often reflect common motor patterns.  If this is true, then the brain is pre-wired for both optimism and love, but also fear.  This explains the broad role of the amygdala in emotional learning [23] including fear learning.  It also means that a neonate needs to develop both love and fear.

A recent paper showed that the corticosterone response required to learn fear is suppressed in the neonate to facilitate attachment, but with enough stress, the corticosterone levels build to the point where amygdala fear learning can commence [24].  The fear circuits are already present, only their development is suppressed.  Analysis of the cohort of children in the Bucharest Early Intervention Project showed that negative affect was the same for both groups.  However positive affect and emotional reactivity was significantly reduced in the institutionalised children [25].  If the brain is truly wired for optimism and only fear is learned, then positive emotional reactivity should be the same in both groups and the negative affect should be enhanced in the institutionalised cohort.  That the result is reversed confirms that neonates and infants require adequate stimulation of both fear and love pathways to grow into an emotionally robust child, because the brain is pre-wired for both but requires further stimulation for adequate development.

The Mind-Brain Link

If the mind controls the brain and not the other way around as Dr Leaf suggests, why do anti-depressant medications correct depression or anxiety disorders?  There is high-level evidence to show this to be true [26-28].  The same can be said for recent research to show that medications which enhance NDMA receptors have been shown to improve the extinction of fear in anxiety disorders such as panic disorder, OCD, Social Anxiety Disorder, and PTSD [29].

If the mind controls the brain and not the other way around as Dr Leaf suggests, why do some people with acquired brain injuries or brain tumours develop acute personality changes or thought disorders?  Dr Leaf has done PhD research on patients with closed head injuries and treated them in clinical settings according to her CV.  She must be familiar with this effect.

One can only conclude that there is a bi-directional effect between the brain and the stream of thought, which is at odds with Dr Leaf’s statement that the mind controls the brain and not the other way around.


One further thing.  Can you clarify which of Dr Leaf’s peer-reviewed articles have definitively shown the academic improvement in the cohort of 100,000 students, as you and your referee have stated?  And can you provide a list of articles which have cited Dr Leaf’s Geodesic Information Processing Model?  Google Scholar did not display any articles that had cited it, which must be an error on Google’s part.  If her theory is widely used as you say, it must have been extensively cited.

I understand that you are both busy, but I believe that I have documented a number of observations, backed by recent peer-reviewed scientific literature, which directly contradict Dr Leaf’s teaching.  I have not had a chance to touch on many, many other points of disagreement.

For the benefit of Dr Leaf’s followers, and for the scientific and Christian community at large, I would appreciate your response.

I would be grateful if you could respond to the points raised and the literature which supports it, rather than an Ad Hominem dismissal or further defense by association.

Dr C. Edward Pitt


1. Fowler, G., Evidence-based practice: Tools and techniques. Systems, settings, people: Workforce development challenges for the alcohol and other drugs field, 2001: 93-107.

2. Mara, D., et al., Sanitation and health. PLoS Med, 2010. 7(11): e1000363.

3. Bartram, J. and Cairncross, S., Hygiene, sanitation, and water: forgotten foundations of health. PLoS Med, 2010. 7(11): e1000367.

4. Hunter, P.R., et al., Water supply and health. PLoS Med, 2010. 7(11): e1000361.

5. FMRC. Public BEACH data. 2010  16JUL13]; Available from: <http://sydney.edu.au/medicine/fmrc/beach/data-reports/public&gt;.

6. Siegel, R., et al., Cancer statistics, 2013. CA Cancer J Clin, 2013. 63(1): 11-30.

7. Cussenot, O. and Valeri, A., Heterogeneity in genetic susceptibility to prostate cancer. Eur J Intern Med, 2001. 12(1): 11-6.

8. Alberti, C., Hereditary/familial versus sporadic prostate cancer: few indisputable genetic differences and many similar clinicopathological features. Eur Rev Med Pharmacol Sci, 2010. 14(1): 31-41.

9. Nickels, S., et al., Evidence of gene-environment interactions between common breast cancer susceptibility loci and established environmental risk factors. PLoS Genet, 2013. 9(3): e1003284.

10. Berrettini, W.H. and Doyle, G.A., The CHRNA5-A3-B4 gene cluster in nicotine addiction. Mol Psychiatry, 2012. 17(9): 856-66.

11. Hutter, C.M., et al., Characterization of gene-environment interactions for colorectal cancer susceptibility loci. Cancer Res, 2012. 72(8): 2036-44.

12. Yusuf, S., et al., Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet, 2004. 364(9438): 937-52.

13. Asselbergs, F.W., et al., Large-scale gene-centric meta-analysis across 32 studies identifies multiple lipid loci. Am J Hum Genet, 2012. 91(5): 823-38.

14. Wu, Y.L., et al., Risk factors and primary prevention trials for type 1 diabetes. Int J Biol Sci, 2013. 9(7): 666-79.

15. Ali, O., Genetics of type 2 diabetes. World J Diabetes, 2013. 4(4): 114-23.

16. Murea, M., et al., Genetic and environmental factors associated with type 2 diabetes and diabetic vascular complications. Rev Diabet Stud, 2012. 9(1): 6-22.

17. Kunes, J. and Zicha, J., The interaction of genetic and environmental factors in the etiology of hypertension. Physiol Res, 2009. 58 Suppl 2: S33-41.

18. Wiedemann, K., et al., Anxiolyticlike effects of atrial natriuretic peptide on cholecystokinin tetrapeptide-induced panic attacks: preliminary findings. Arch Gen Psychiatry, 2001. 58(4): 371-7.

19. Ronco, C., Fluid overload : diagnosis and management. Contributions to nephrology,. 2010, Basel Switzerland ; New York: Karger. viii, 243 p.

20. Riegel, B., et al., State of the science: promoting self-care in persons with heart failure: a scientific statement from the American Heart Association. Circulation, 2009. 120(12): 1141-63.

21. Arnold, C. Gut feelings: the future of psychiatry may be inside your stomach. 2013  [cited 2013 Aug 22]; Available from: http://www.theverge.com/2013/8/21/4595712/gut-feelings-the-future-of-psychiatry-may-be-inside-your-stomach.

22. Hobson, J.A., REM sleep and dreaming: towards a theory of protoconsciousness. Nat Rev Neurosci, 2009. 10(11): 803-13.

23. Dalgleish, T., The emotional brain. Nat Rev Neurosci, 2004. 5(7): 583-9.

24. Landers, M.S. and Sullivan, R.M., The development and neurobiology of infant attachment and fear. Dev Neurosci, 2012. 34(2-3): 101-14.

25. Bos, K., et al., Psychiatric outcomes in young children with a history of institutionalization. Harv Rev Psychiatry, 2011. 19(1): 15-24.

26. Arroll, B., et al., Antidepressants versus placebo for depression in primary care. Cochrane Database Syst Rev, 2009(3): CD007954.

27. Soomro, G.M., et al., Selective serotonin re-uptake inhibitors (SSRIs) versus placebo for obsessive compulsive disorder (OCD). Cochrane Database Syst Rev, 2008(1): CD001765.

28. Kapczinski, F., et al., Antidepressants for generalized anxiety disorder. Cochrane Database Syst Rev, 2003(2): CD003592.

29. Davis, M., NMDA receptors and fear extinction: implications for cognitive behavioral therapy. Dialogues Clin Neurosci, 2011. 13(4): 463-74.