Dr Caroline Leaf and the chemistry of perceptions

Screen Shot 2014-11-16 at 3.19.48 pm

On her social media feed just now, Dr Caroline Leaf, communication pathologist and self-titled cognitive neuroscientist, said, “Your perceptions adjust your brain chemistry”.

Hmmm … yes and no.

I’m not really sure what Dr Leaf is trying to suggest with this statement, because it’s so vague. The brain works through the passage of an electrical current travelling along a nerve cell, and being passed to the next nerve cell by the release of a “chemical” neurotransmitter that floats across the space between the nerve cells.  If that’s what Dr Leaf is referring when she talks about our brain chemistry, then sure, our perceptions adjust our brain chemistry. But then again, so does everything else that our brain does. In this sense, perception is nothing special.

What I think Dr Leaf was trying to suggest is that our mind influences our brain chemistry, following along with her “mind controls matter” theme. But perception is the process of translating the raw data into a signal that the brain can process, for example, the light coming into your eye is translated into the electrical impulses your brain can utilise. It’s not an explicit process. It has nothing to do with our consciousness or our volition.

Also, our “brain chemistry” as it’s considered in neuroscience is usually referring to the neurotransmitters and their function, which is often determined by our genetics and influences how we perceive and understand our environment [1].

So if anything, it’s not our perception altering our brain chemistry, but rather it’s our brain chemistry that alters our perceptions.

Our mind does not control our brain. Our brain is responsible for the function of our mind.


  1. Caspi, A., et al., Genetic sensitivity to the environment: the case of the serotonin transporter gene and its implications for studying complex diseases and traits. Am J Psychiatry, 2010. 167(5): 509-27 doi: 10.1176/appi.ajp.2010.09101452

Dr Caroline Leaf and the tongues trivia tall tales

Screen Shot 2014-11-12 at 9.29.17 pm

In every day life, if someone started talking in strings of indecipherable, chaotic syllables, you’d be giving them quite a lot of space, concerned about how much methamphetamine they’d been using.

In the average charismatic church, it’s just another service (the speaking in tongues, not the meth).

I’ve grown up in Pentecostal churches, and was baptised in the Holy Spirit when I was a child, so I forget how freaky it is for those who’ve never seen a whole church start talking or singing in tongues. For the uninitiated, the Bible talks about speaking in other tongues, which is a “New Testament phenomena where a person speaks in a language that is unknown to him. This language is either the language of angels or other earthly languages (1 Cor. 13:1). It occurred in Acts 2 at Pentecost and also in the Corinthian church as is described in 1 Corinthians 14. This New Testament gift was given by the Holy Spirit to the Christian church and is for the purpose of the edification of the Body of Christ as well as for glorifying the Lord.” (http://carm.org/speaking-in-tongues)

In scientific terms, speaking in tongues is referred to as “Glossolalia”, from the Greek, ‘glosso-‘ ~ ‘the tongue’ and ‘-lalia’ ~ ‘to speak, to chat’. Scientists who initially studied it in the 60’s and 70’s drew the conclusion that glossolalia was related to psychopathology (that people who spoke in tongues were crazy) [1, 2], and in later decades, it was thought to be caused by a form of temporal lobe epilepsy [3].

Earlier today, Dr Caroline Leaf, a communication pathologist and self-titled cognitive neuroscientist, declared that, “When we speak in tongues, research shows that the areas involved in discernment in the brain increase in activity, which means we increase in wisdom.”

I was fascinated to find this research for myself. Dr Leaf never references her social media memes, so I started looking through the medical literature on the subject from respected databases like PubMed, and search engines like Google Scholar.

Despite a thorough search, I was only able to find one article that studied the pattern of brain activity during speaking in tongues. The article, “The measurement of regional cerebral blood flow during glossolalia: A preliminary SPECT study” [4] took five healthy women, psychiatrically stable, long term members of their churches, who had all spoken in tongues for many years. They scanned their brain activity after a period of singing to gospel songs in English and compared it to their brain activity after the same amount of time praying in tongues (while listening to the same music as before).

What they found was that the brain was more active in the left superior parietal lobe, while there was a decrease in brain activity in the prefrontal cortices, left caudate nucleus and left temporal pole. There was a trend for an increase in the activity of the right amygdala, but this may have just been chance.

So are any of those brain regions responsible for discernment as Dr Leaf suggested?

Well, that all depends on how you define “discernment”. “Discernment” is not really a common neurobiological term. The standard term in the literature is “judgement”. The brain regions that are associated with evaluation and judgement are the amygdala and ventral portions of the striatum as well as the ventromedial prefrontal cortex (vmPFC), orbitofrontal cortex (OFC), the insula, the dorsal anterior cingulate cortex (dACC), and the periaqueductal gray (PAG) [5].

Are there any parts of the brain that match in the two lists? Only one – the ventromedial prefrontal cortex, or vmPFC for short. The prefrontal cortex is important in reasoning and decision-making, especially if there is uncertainty or novelty, while the vmPFC in particular is involved in the use of goal-relevant information in guiding responses, e.g., assigning value to choice options [6].

According to Dr Leaf, “When we speak in tongues, research shows that the areas involved in discernment in the brain increase in activity”. But that’s certainly not what the research paper said. The actual research is entirely the opposite.

Again, there are really only two reasonable explanations as to why the research contradicts Dr Leaf; either there is another piece of research which supports Dr Leaf’s assertion, or Dr Leaf is simply wrong.

At the risk of repeating myself, Dr Leaf needs to quote her sources when she is writing her little social media memes. Her meme may be perfectly justified by robust scientific evidence, but if she isn’t willing to share her sources, we’ll never know, and the only conclusion remaining is that Dr Leaf can’t interpret simple research.

So as it stands, there really isn’t any evidence that speaking in tongues makes you more discerning. By trying to claim otherwise, Dr Leaf further undermines her own reputation and credibility as an expert.


  1. Hine, V.H., Pentecostal glossolalia: towards a functional reinterpretation. Journal for the Scientific Study of Religion, 1969. 8: 212-26
  2. Brende, J.O. and Rinsley, D.B., Borderline disorder, altered states of consciousness, and glossolalia. J Am Acad Psychoanal, 1979. 7(2): 165-88 http://www.ncbi.nlm.nih.gov/pubmed/370074
  3. Persinger, M.A., Striking EEG profiles from single episodes of glossolalia and transcendental meditation. Perceptual and Motor Skills, 1984. 58: 127-33
  4. Newberg, A.B., et al., The measurement of regional cerebral blood flow during glossolalia: a preliminary SPECT study. Psychiatry Res, 2006. 148(1): 67-71 doi: 10.1016/j.pscychresns.2006.07.001
  5. Doré, B.P., et al., Social cognitive neuroscience: A review of core systems, in APA Handbook of Personality and Social Psychology, Mikulincer, M., et al., (Eds). 2014, American Psychological Association: Washington, DC. p. 693-720.
  6. Nicolle, A. and Goel, V., What is the role of ventromedial prefrontal cortex in emotional influences on reason?, in Emotion and Reasoning, Blanchette, I., (Ed). 2013, Psychology Press.

STOP THE PRESSES! Dr Leaf releases a new meme based on my correction, still doesn’t acknowledge source. (13 November 2014)

Screen Shot 2014-11-13 at 8.08.23 am


So, I can’t find fault on what Dr Leaf said here.  It fits with the paper I quoted from Newberg et al (2006).  Still, it begs the question of why Dr Leaf couldn’t have said this in the first place, and why she still isn’t willing to share her citations?

It also raises the other obvious question, why is it important to know what our brain does in glossolalia?  It’s only a study of 5 patients, and I’m sure that not all episodes of speaking in tongues is associated with decreased intentionality.  The research, being so small, isn’t a true reflection of the practice of speaking in tongues.  Lets hope that the future will bring more funding to better study this central tenet to the charismatic faith.

Dr Caroline Leaf: Putting thought in the right place

Following hard on the heels of her false assumption that our mins control our health, not our genes, and following the same theme, Dr Leaf had this to say today, “Everything is first a thought; the brain is being controlled with EVERY thought you think!”

Dr Caroline Leaf is a communication pathologist and a self-titled cognitive neuroscientist. Reading back through my blogs, this “thought controls the brain / mind controls matter” is a recurrent theme of hers. It is repeated multiple times in her books, like when she writes, “Thoughts influence every decision, word, action and physical reaction we make.” [1: p13] and “Our mind is designed to control the body, of which the brain is a part, not the other way around. Matter does not control us; we control matter through our thinking and choosing” [2: p33] just as a couple of examples.

So how does thought relate to the grand scheme of our brain and it’s processing? Does our thought really control our brain, or is it the other way around. Through all of the reading that I have done on neuroscience, I propose a model of the place of thought in relation to the rest of our brains information processing. It is based on the LIDA model, dual systems models, and other neuroscientific principles and processes.

We’ve all heard the phrase, “It’s just the tip of the iceberg.” It comes from the fact that icebergs are made of fresh water, which is nine-tenths less dense than seawater. As a result, ten percent of an iceberg sits above the waters surface with most of it hiding beneath.

The information processing of our brains is much the same. We may be aware of our conscious stream of thought, but there is a lot going on under the surface that makes our thoughts what they are, even though we can’t see the process underneath.

What’s going on under the surface is a complex interplay of our genes and their expression which controls the structure and function of our brains, which effects how we perceive information, how we process that information and combine it into our memories of the past, predictions of the future, and even the further perception of the present [3].

CAP v2.1.2

Genes, epigenetics and the environment

We start with the most fundamental level of our biological system, which is genetics. It becomes clear from looking at any textbook of biological sciences that genes are fundamental to who we are. From the simplest bacteria, fungi, protozoans and parasites, through to all plants, all animals and all of human kind – EVERY living thing has DNA. DNA is what defines life in the broadest sense.

Proteins are responsible for the size, shape and operation of the cell. They make each tissue structurally and functionally different, but still work together in a highly precise electrochemical synchrony. But ultimately, it’s our genes that hold all of the instructions to make every one of the proteins within our cells. Without our genes, we would be nothing more than a salty soup of random amino acids.

Epigenetics and the environment contribute to the way genes are expressed. Epigenetics are “tags” on the strand of DNA that act to promote or silence the expression of certain genes (this will be discussed in more detail in chapter 12). Environmental factors (the components that make up the world external to our bodies) can influence genes and epigenetic markers. The environment can cause genetic mutations or new epigenetic marks that change the function of a particular gene, and depending on which cell they effect (a very active embryonic cell or a quiet adult cell) will largely determine the eventual outcome. The environment is more influential to our genetic expression than epigenetics.

Still, on average only about 25% of the expression of a complex trait is related to environmental factors. So while the environment is important, it is still outdone 3:1 by our genome.

Yes, epigenetics and the environment are important, but they influence, not control, the genome.


We live in a sensory world. The five senses are vital in providing the input we need for our brain to understand the world and meaningfully interact with it.

Different organs are needed to translate the optical, chemical or mechanical signals into electrical signals. Different parts of our brain then interpret these signals and their patterns. We discussed this in more detail in chapter 1.

Our genes significantly influence this process. For example, if someone is born with red-green colour blindness then how he or she interprets the world will always be subtly different to someone with normal vision. Or a person born with congenital deafness will always interpret his or her environment in a different way to someone with full hearing. I’ve highlighted these two conditions because they provide stark examples to help demonstrate the point, but there are many unique genetic expressions in each of the five senses that subtly alter the way each of us perceives the world around us.

So while we may all have the same photons of light hitting our retinas, or the same pressure waves of sound reaching our ears or touch on our skin, how our brains receive that information is slightly different for every individual. The information from the outside world is received by our sensory organs, but it is perceived by our brain, and even small differences in perception can have a big impact on the rest of the system.


Personality is “the combination of characteristics or qualities that form an individual’s distinctive character” [4]. Formally speaking, personality is, “defined as constitutionally based tendencies in thoughts, behaviors, and emotions that surface early in life, are relatively stable and follow intrinsic paths of development basically independent of environmental influences.” [5]

Professor Gregg Henriques explained it well in Psychology Today, “Personality traits are longstanding patterns of thoughts, feelings, and actions which tend to stabilize in adulthood and remain relatively fixed. There are five broad trait domains, one of which is labeled Neuroticism, and it generally corresponds to the sensitivity of the negative affect system, where a person high in Neuroticism is someone who is a worrier, easily upset, often down or irritable, and demonstrates high emotional reactivity to stress.” [6] The other four personality types are Extraversion, Agreeableness, Conscientiousness, and Openness to Experience.

Gene x environment studies suggest that personality is highly heritable, with up to 60% of personality influenced by genetics [7], predominantly through genes involved in the serotonin [8] and dopamine systems [9, 10]. The “non-shared environment” (influences outside of the home environment) contributes heavily to the remainder [11, 12].

Personality is like a filter for a camera lens, shaping the awareness of our emotional state for better or worse, thus influencing the flow on to our feelings (the awareness of our emotions), our thoughts, and our actions.


Watkins describes physiology as streams of data that are provided from the different parts of your body, like the heart rate, your breathing rate, the oxygen in your blood, the position of your joints, the movement of your joints, even the filling of your bladder telling you that you need a break soon.

All of these signals are constantly being generated, and collated in different parts of the brain. Some researchers consider them positive and negative depending on the data stream and the signal its providing. They coalesce into emotion [13].


According to Watkins, “emotion” is the sum of all the data streams of physiology, or what he described as “E-MOTIONEnergy in MOTION.” [13] In this context, think of emotion as a bulls-eye spirit-level of our body systems. The different forces of our physiology change the “level” constantly in different directions. Emotion is the bubble that marks the central point, telling us how far out of balance we are.

In the interest of full disclosure, I should mention that although emotion is a familiar concept, the work of literally thousands of brilliant minds has brought us no closer to a scientifically validated definition of the word “emotion”. Some psychologists and researchers consider it vague and unscientific, and would prefer that it not be used altogether [14].

I’ve retained it because I think it’s a well-recognised word that conceptually describes the balance of physiological forces.


“Feelings” are the perception of emotion.

I discussed earlier in the chapter that what we perceive is different to what we “see” because the subtle genetic differences in our eyes and brains causes the information to be processed differently between individuals. The same applies to the perception of our emotion.

As I wrote earlier, personality is largely determined by our genetics with contributions from our environment [11, 12]. The emotional signal is filtered by our personality to give rise to our feelings. Classically, an optimistic personality is going to bias the emotional input in a positive, adaptive way while a pessimist or neurotic is going to bias the emotional signal in a maladaptive way

That’s not to say that an optimist can’t have depressed feelings, or a neurotic can’t have happy feelings. In the same way that a coloured lens will allow a lot of light through but filter certain wavelengths out, most of our emotional state of being will come through the filter of our personality but the feelings will be subtly biased one way or another.

Executive Functions

Executive function of the brain is defined as a complex cognitive process requiring the co-ordination of several sub-processes to achieve a particular goal [15]. These sub-processes can be variable but include working memory, attention, goal setting, maintaining and monitoring of goal directed action and action inhibition. In order to achieve these goals, the brain requires flexibility and coordination of a number of networks and lobes, although mainly the prefrontal cortex, parietal cortex, anterior cingulate and basal ganglia, and the while matter tracts that connect them.

Executive functions process the incoming information and decide on what goals are best given the context, then plan the goals, execute them to the motor cortices, and monitor the action. Research work from Marien et al [16] demonstrates that unconscious/implicit goals can divert resources away from conscious goals especially if it is emotionally salient or otherwise strongly related. They also confirm that conscious awareness is not necessary for executive function but that implicit goals can be formed and executed without conscious involvement.


In chapter one we discussed the conscious broadcast model of thought. Baars [17, 18] noted that the conscious broadcast comes into working memory which then engages a wider area of the cerebral cortex necessary to most efficiently process the information signal. We perceive thought most commonly as either pictures or sounds in our head (“the inner monologue”), which corresponds to the slave systems of working memory. When you “see” an image in your mind, that’s the visuospatial sketchpad. When you listen to your inner monologue, that’s your phonological loop. When a song gets stuck in your head, that’s your phonological loop as well, but on repeat mode.

There is another slave system that Baddeley included in his model of working memory called the episodic buffer, “which binds together complex information from multiple sources and modalities. Together with the ability to create and manipulate novel representations, it creates a mental modeling space that enables the consideration of possible outcomes, hence providing the basis for planning future action.” [19]

Deep thinking is a projection from your brains executive systems (attention or the default mode network) to the central executive of working memory, which then recalls the relevant information from long-term memory and directs the information through the various parts of the slave systems of working memory to process the complex details involved. For example, visualizing a complex scene of a mountain stream in your mind would involve the executive brain directing the central executive of working memory to recall information about mountains and streams and associated details, and project them into the visuospatial sketchpad and phonological loop and combine them via the episodic buffer. The episodic buffer could also manipulate the scene if required to create plans, or think about the scene in new or unexpected ways (like imagining an elephant riding a bicycle along the riverbank).

Even though the scene appears as one continuous episode, it is actually broken up into multiple cognitive cycles, in the same way that images in a movie appear to be moving, but are really just multiple still frames played in sequence.


Action is the final step in the process, the output, our tangible behaviour

Our behaviour is not the direct result of conscious thought, or our will (as considered in the sense of our conscious will)

We discussed this before when we talked about our choices in chapter 1. There are two main pathways that lead from sensory input to tangible behaviour – various automated pathways that take input from the thalamus, deep in the brain, and sent to motor circuits in the supplementary motor area and motor cortex of the brain. These can be anything from evasive “reflex” actions[1] to rehearsed, habituated motor movements, like driving. Then there is the second pathway, coming from the executive areas of our brain, that plan out options for action, which are reviewed by the pre-supplemental motor area and the default mode network.

This second pathway is amenable to conscious awareness. Like thought, the projection of different options for action into our consciousness helps to engage a wider area of cerebral cortex to process the data. Most of the possible plans for action have already been rejected by the implicit processing of our executive brain before consciousness is brought in to help. Once an option has been selected, the action is sent to the pre-supplementary motor area, the supplementary motor area, the basal ganglia and finally the motor cortex.

According to the model proposed by Bonn [20], the conscious network has some feedback from the control network of our brain, providing real time context to actions about to be executed, and a veto function, stopping some actions at the last minute before they are carried out. This is largely a function of the basal ganglia [21], with some assistance from working memory.

So as you can see, according to the CAP model, conscious thoughts are one link of a longer chain of neurological functions between stimulus and action – simply one cog in the machine. Thoughts are dependent on a number of processes that are both genetically and environmentally determined, beyond our conscious control. It’s simply wrong to assume that thoughts control the brain.

Dr Leaf is welcome to her opinion, but it is in contradiction to the overwhelming majority of neuroscientific knowledge


  1. Leaf, C., Who Switched Off My Brain? Controlling toxic thoughts and emotions. 2nd ed. 2009, Inprov, Ltd, Southlake, TX, USA:
  2. Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:
  3. Hao, X., et al., Individual differences in brain structure and resting brain function underlie cognitive styles: evidence from the embedded figures test. PLoS One, 2013. 8(12): e78089 doi: 10.1371/journal.pone.0078089
  4. Oxford Dictionary of English – 3rd Edition, 2010, Oxford University Press: Oxford, UK.
  5. De Pauw, S.S., et al., How temperament and personality contribute to the maladjustment of children with autism. J Autism Dev Disord, 2011. 41(2): 196-212 doi: 10.1007/s10803-010-1043-6
  6. Henriques, G. (When) Are You Neurotic? Theory of Knowledge: Psychology Today; 2012, 23 Nov 2012 [cited 2013 23 Nov 2012]; Available from: http://www.psychologytoday.com/blog/theory-knowledge/201211/when-are-you-neurotic.
  7. Vinkhuyzen, A.A., et al., Common SNPs explain some of the variation in the personality dimensions of neuroticism and extraversion. Transl Psychiatry, 2012. 2: e102 doi: 10.1038/tp.2012.27
  8. Caspi, A., et al., Genetic sensitivity to the environment: the case of the serotonin transporter gene and its implications for studying complex diseases and traits. Am J Psychiatry, 2010. 167(5): 509-27 doi: 10.1176/appi.ajp.2010.09101452
  9. Felten, A., et al., Genetically determined dopamine availability predicts disposition for depression. Brain Behav, 2011. 1(2): 109-18 doi: 10.1002/brb3.20
  10. Chen, C., et al., Contributions of dopamine-related genes and environmental factors to highly sensitive personality: a multi-step neuronal system-level approach. PLoS One, 2011. 6(7): e21636 doi: 10.1371/journal.pone.0021636
  11. Krueger, R.F., et al., The heritability of personality is not always 50%: gene-environment interactions and correlations between personality and parenting. J Pers, 2008. 76(6): 1485-522 doi: 10.1111/j.1467-6494.2008.00529.x
  12. Johnson, W., et al., Beyond Heritability: Twin Studies in Behavioral Research. Curr Dir Psychol Sci, 2010. 18(4): 217-20 doi: 10.1111/j.1467-8721.2009.01639.x
  13. Watkins, A. Being brilliant every single day – Part 1. 2012 [cited 2 March 2012]; Available from: http://www.youtube.com/watch?v=q06YIWCR2Js.
  14. Dixon, T., “Emotion”: The History of a Keyword in Crisis. Emot Rev, 2012. 4(4): 338-44 doi: 10.1177/1754073912445814
  15. Elliott, R., Executive functions and their disorders Imaging in clinical neuroscience. British Medical Bulletin, 2003. 65(1): 49-59
  16. Marien, H., et al., Unconscious goal activation and the hijacking of the executive function. J Pers Soc Psychol, 2012. 103(3): 399-415 doi: 10.1037/a0028955
  17. Baars, B.J. and Franklin, S., How conscious experience and working memory interact. Trends Cogn Sci, 2003. 7(4): 166-72 http://www.ncbi.nlm.nih.gov/pubmed/12691765 ; http://bit.ly/1a3ytQT
  18. Baars, B.J., Global workspace theory of consciousness: toward a cognitive neuroscience of human experience. Progress in brain research, 2005. 150: 45-53
  19. Repovs, G. and Baddeley, A., The multi-component model of working memory: explorations in experimental cognitive psychology. Neuroscience, 2006. 139(1): 5-21 doi: 10.1016/j.neuroscience.2005.12.061
  20. 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
  21. Beste, C., et al., Response inhibition subprocesses and dopaminergic pathways: basal ganglia disease effects. Neuropsychologia, 2010. 48(2): 366-73 doi: 10.1016/j.neuropsychologia.2009.09.023

[1] We often describe rapid unconscious movements, especially to evade danger or to protect ourselves, as “reflexes”. Medically speaking, a true reflex is a spinal reflex, like the knee-jerk reflex. When a doctor taps the knee with the special hammer, the sudden stretch of the tendon passes a nerve impulse to the spinal cord, which is then passed to the muscle, which makes it contract. A true reflex doesn’t go to the brain at all.

Dr Caroline Leaf and the matter of mind over genes

Screen Shot 2014-11-07 at 8.13.45 pm

I think I might have to throw away my genetics textbook.

I was always taught that genes were the main driver behind health and disease, and I always thought it was a pretty good theory.

But not according to Dr Caroline Leaf, communication pathologist and self-titled cognitive neuroscientist, who said on her social media feeds today, “Our health is not controlled by genetics – our health is controlled by our mind.”

Taking her statement at face value, she appears to be saying that genes have nothing to do with our health. Dr Leaf has made some asinine statements in the past, but to suggest that genes are irrelevant to human health seemed so stupid that no one in their right mind would suggest such a thing.

Perhaps I was taking her statement the wrong way? I wanted to make sure I didn’t jump to any rash conclusions about Dr Leaf’s statement, so I pondered it at length. Could she be referring to ‘control’ in the absolute sense? How much control do genes have on our health? What about the mind?

After deliberating for a while, I still came to the conclusion that Dr Leaf’s statement was nonsense.

Unfortunately, Dr Leaf’s statement is, like so many of her previous Facebook memes, so vague as to be misleading. The meaning of ‘health’ and ‘controlled’ could be taken so many ways … which part of our health? How much regulation constitutes ‘control’? What about genetics?

Looking at her statement in more depth, it becomes clear that no matter which way Dr Leaf meant it, it’s still wrong. For example, all of human health is controlled, in part, by genetics. That’s because life itself is controlled by genetics. The human genome provides a blueprint for the construction of all of the proteins in all of the cells in our entire body. The expression of those genes determines exactly how our body will run. If the genes are wrong, if the translation of the gene code into a protein is wrong, or if too much or too little of a protein is made, all determines whether our body is functioning at its optimum level or not.

The stimulus for the expression of our genes is influenced by the environment in which we live. If I go out into the sun a lot, the UV light triggers my skin cells to make the protein melanin, which makes my skin go darker and helps to provide some protection against the damaging effects of the UV light.

While the environment plays a part of the expression of some genes, it’s wrong to say that genetics doesn’t control the process. If I go into the sun too much, I risk developing a melanoma, because the sun damages the genes in some of my skin cells, causing them to grow without control.

Genes are still responsible for the disease itself. Sometimes the trigger is from the environment, sometimes it’s not. There are some people with genes for melanoma who don’t need an environmental trigger, because they develop melanoma on skin that’s exposed to very little UV light, like the genital skin.

So fundamentally, even taking the environment into account, our health is controlled by our genetics.

The other part of Dr Leaf’s meme is also wrong. Our health is not controlled by our mind. Our genes are influenced by “the environment”, which according to the seminal paper by Ottman, “The environmental risk factor can be an exposure, either physical (e.g., radiation, temperature), chemical (e.g., polycyclic aromatic hydrocarbons), or biological (e.g., a virus); a behavior pattern (e.g., late age at first pregnancy); or a “life event” (e.g., job loss, injury). This is not intended as an exhaustive taxonomy of risk factors, but indicates as broad a definition as possible of environmental exposures.” [1]

Even if one considers the mind as part of the sub classification of “a behavior pattern”, it’s still pretty clear that most of the factors that make up our environment are not related to our mind at all but are related to the external world, of which we have minimal or no control over. Sure, we make choices, but our choices aren’t truly free. They’re constrained by the environment in which we find ourselves. In the same way, our mind may have some tiny influence on our health, but only insofar as our environment and our genes will allow.

When it all boils down, this meme of Dr Leaf’s is rested on her foundational presumption that our mind can control matter, a very strong theme throughout her most recent book [2], but which is still preposterous. Our thoughts are simply a function of our brain, which is in turn determined by the function of our nerve cells, which is in turn a function of our genes and their expression.

Our mind doesn’t control matter. Matter controls our mind.

I can keep my genetics textbooks after all.


  1. Ottman, R., Gene-environment interaction: definitions and study designs. Prev Med, 1996. 25(6): 764-70 http://www.ncbi.nlm.nih.gov/pubmed/8936580
  2. Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:

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 shotgun approach

Screen Shot 2014-10-20 at 8.39.28 pm

“It has been collectively demonstrated by researchers around the world that just about every aspect of our brainpower, intelligence and control – in normal, and psychiatrically and neurologically impaired individuals – can be improved by intense, efficient, organised and appropriately direct mind training … thank you Jesus.”

Sounds impressive doesn’t it.

Unfortunately for Dr Caroline Leaf, communication pathologist and self-titled cognitive neuroscientist, grandstanding does not equate to authority.  It’s all very well and good to publish broad, sweeping generalisations, but it’s like firing a shotgun at a cork from thirty paces.  Sure, you might hit your target, but the scatter pattern of the ammunition misses more times than it hits.

If Dr Leaf wants her statement to be taken seriously, then she needs to do a couple of small things.
(1) Reference her statement.  This should be fairly easy if “researchers around the world” really have demonstrated the power of mind training.  To sum it up more effectively, perhaps Dr Leaf could cite a meta-analysis that proves the value of mind training.
(2) Stop confusing the mind with the brain. This is the biggest problem with her statement. The mind does not control the brain.  If Dr Leaf produced any references in support of her statement, they would be along the lines of training or retraining the brain, not the mind.

It may seem trivial, because most people think the mind and the brain are the same, but they’re two distinct things.  Old psychological therapies were based upon the notion that fixing your thoughts was the key to improving your mental health, but this notion is now outdated, considered part of “Western folk psychology” [1]. By using the concept of “mind” and “brain” interchangeably, Dr Leaf confuses the issue for the average person trying to come to grips with modern science.

I’d be grateful if Dr Leaf could publish some evidence to support her claim, because I’m unfamiliar with research showing that things like intelligence can be improved with brain training. Sure, there’s good evidence for the improvement in the damaged brain with specific physical exercises – it’s one of the primary tools in Rehabilitation Medicine. There is also good evidence for psychological therapies such as ACT, or Acceptance and Commitment Therapy, in improving mood amongst other things [2, 3]. Though I’ve read a recent meta-analysis of multiple studies that suggests “brain training” for working memory offers minimal benefit which is not maintained and not transferable across categories [4], which means there’s no proof that “brain training” improves intelligence.

In future posts, I hope that Dr Leaf provides something more accurate instead of grandiose shotgun statements.


  1. Herbert, J.D. and Forman, E.M., The Evolution of Cognitive Behavior Therapy: The Rise of Psychological Acceptance and Mindfulness, in Acceptance and Mindfulness in Cognitive Behavior Therapy. 2011, John Wiley & Sons, Inc. p. 1-25.
  2. 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
  3. Harris, R., The happiness trap : how to stop struggling and start living. 2008, Trumpeter, Boston:
  4. Melby-Lervag, M. and Hulme, C., Is working memory training effective? A meta-analytic review. Dev Psychol, 2013. 49(2): 270-91 doi: 10.1037/a0028228


Labels – the good, the bad, and the ugly

Yesterday, I wrote a rebuttal to Dr Caroline Leaf’s social media post, that “Psychiatric labels lock people into mental ill-health.” In my rebuttal, I suggested that psychiatric labels don’t lock anyone into mental ill-health any more than a medical diagnosis locks people into physical ill-health.

In the feedback I received, one intelligent young lady commented that, “I understand your point completely, but I took her words differently. I have often seen people who use their diagnosis as an excuse. For example, a kid gets diagnosed with Autism or ADHD, and suddenly the parents are using that as an excuse for their bad behaviour instead of teaching and helping them to deal with it. Another example, an adult is diagnosed with something mild, but uses it as an excuse to no longer care about trying to get a job or trying to get treatment and make an effort to get better”.

I certainly understand where she’s coming from. I’ve seen it too. A diagnosis is used as an excuse for someone’s avoidance, or a tool to milk every drop of sympathy from another. Giving someone a label seems to hinder some people more than help them.

Thankfully, there’s more than one side to the label story. I wanted to use today’s post to discuss the good, the bad, and the ugly side of diagnostic labels.

First, lets look at the ugly side of a diagnostic label. There will always be emotional and social connotations to every diagnosis that a person receives. Sometimes that’s sympathy, and sometimes that’s stigma. If a young woman told her friends that she had breast cancer, I’m sure that news would be met with an outpouring of care and support. If the same young woman told the same friends that she had chlamydia or genital herpes, I’d bet that most of the responses would be blaming or shaming, which is one reason why no one tells other people they’ve got chlamydia or herpes.

The same goes for mental health. The media often portrays people with mental illness as either homicidal or weak [1]. So the general response to mental health diagnoses is either fear or contempt. Even those who are neutral towards mental health often don’t understand it, so it’s difficult for those with mental health issues to receive true empathy for their plight.

Then, there is the bad side of a label. Labels can be misused, intentionally or unintentionally, for all sorts of reasons. They can also be wrongly applied. It might be that someone uses their diagnosis to draw sympathy from people, or money, or help when they don’t really need it. They might use their label as an excuse to avoid certain things they don’t like. There are innumerable ways that people can milk secondary gain from their problems.

However, appropriate diagnosis can bring many benefits. For example, correct labelling brings with it understanding and empowerment.

A diagnosis can help us understand more about ourselves, or the person with the diagnosis. That child with ADHD isn’t just being naughty, but has difficulty regulating their behaviour. That person with Asperger’s isn’t being intentionally rude, but has trouble with social cues, understanding body language, and communicating in an empathic way. A correct diagnosis also helps us understand our own strengths and weaknesses. They help us recognise what it is about ourselves that we can’t change, what we can change, and what we need to change.

Once you understand what it is you can change and what you can’t change, it empowers you to change what you can for the better, and accept and adapt to what you can’t change. You stop wasting precious strength and time fighting what you can’t change. Instead, all of the effort that would have been needlessly spent on the unchangeable can be effectively spent on improving what needs to be, and can be, changed.

In fairness, I should point out that a diagnosis isn’t always needed to make positive change. Acceptance and Commitment Therapy is a form of psychological therapy that encourages flexibility to accept those parts of our lives that are uncomfortable, whether they have a label or not, and allow our values to shape our life direction. Sometimes we can spend so much energy looking for a diagnosis that we stagnate, forgoing the forward momentum of what we value to focus on having a label for the symptoms.

But where a diagnosis can be made without undue effort, it can provide clarity to what often seems to be a jumbled mess of dysfunctional traits.

So, sure, sometimes labels can be used for the wrong things. That doesn’t mean they’re not useful or we should stop using them. There may be a stigma to a diagnosis of herpes or depression, but there are also good treatments available. The diagnosis may provide a way of changing a life of ongoing suffering to a life fulfilled.

More often than not, a good diagnosis helps bring clarity to a situation, enabling understanding, acceptance and empowerment. Rather than locking people in, a correct label usually unlocks a person’s potential to grow despite the problems they face.


  1. Corrigan, P.W. and Watson, A.C., Understanding the impact of stigma on people with mental illness. World Psychiatry, 2002. 1(1): 16-20 http://www.ncbi.nlm.nih.gov/pubmed/16946807