Mac Leaf responds to “Dr Caroline Leaf – Serious Questions, Few Answers”

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, here is his reply, complete and unabridged.  My further response is posted here.

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 or my reply are welcome provided they are constructive.

Hi Dr C. Pit,

It is a pity you did not seek to clarify the comments you have posted above with us before you posted them. We hope you allow our comments to be displayed so that your readers can make informed decisions and not to judge Dr Leaf as you have done without getting accurate information. By your comments it is obvious that you have not kept up to date with the latest Scientific research.

Dr Leaf can call herself a Cognitive Neuroscientist because of her field research (published in peer evaluated Journals) …see the Science articles in the media/downloads section at If you require, we can also send letters from her peers in the field of Neuroscience

She also developed the Geodesic Information Processing model theory.

Yes she does read a lot as the field of Neuroscience is constantly evolving and one has to be as informed as possible.

Some research links re the correlation between illness and thought are presented in Dr Leaf’s November the 30th blog at…blog. There are many more statistic correlation research links.

Dr Leaf has listed references differently in the different books and has a full list of references in the ‘thought life’ section at The references were listed simply in that book for the lay person. This is an accepted literary format for the lay person. Subsequent books have fuller references.

The mini brain in the heart research can be found at

Heartmath and Dr Don Colbert both reference the effect of ANF

The wired for optimism bias research has been evidenced by various scientific researchers
For easy access to this research please see the Google links to TED talks and Time Magazine’s article.

Please send us your E-mail address so that we can send you further documentation.

My name is Dr Peter Amua-Quarshie and I am presently a full-time Adjunct Professor (lecturer) at the University of Wisconsin-Stout in Menomonie, Wisconsin. I have a B.Sc (Hons) in Medical Sciences (specializing in Neuropathology) and a Masters of Public Health (MPH), both degrees from the University of Leeds (UK). Additionally I have a medical degree (MB ChB) from the University of Ghana Medical School, Accra, Ghana, and a Master’s of Science (MS) in Behavioral and Neural Sciences from Rutgers University, Newark, New Jersey. I started teaching anatomy in the University of Leeds Medical School in 1996. I have taught Neurochemistry to graduate students and Neuroscience to undergraduates at Delaware State University and the University of Wisconsin respectively. I have known Dr. Caroline Leaf since 2006 and have worked closely with her since 2008 on various projects in the field of cognitive neuroscience.
Caroline Leaf received her training in Communication Pathology (BSC Logopaedics) at the University of Cape Town, South Africa. The University of Cape Town has produced many outstanding graduates, including Max Theiler, a Nobel Prize laureate in Physiology or Medicine and Christaan Barnard, the first person to successfully transplant a human heart. Caroline Leaf was a contemporary to the eminent neuroscientist Henry Markram, director of the Blue Brain Project and the new one billion Euro European Union Flagship Project, the Human Brain Project. As well having to study the cognition, she had to endure the rigor of the first 2 years of the medical course, in which she had to study neuroanatomy and neurophysiology. Dr. Leaf also holds a Master’s degree and PhD in Communication Pathology from the University of Pretoria, South Africa. In her Master’s degree her dissertation concentrated on cognitive neuroscience of Traumatic Brain Injury (Closed Head Injury). In developing her groundbreaking Geodesic Learning™ Theory (brain-compatible learning) in her ground breaking PhD thesis, she examined cognition and neurobiology of thinking. The Geodesic Learning™ Theory has been implemented among approximately 100,000 students in South Africa with great success. I have personally helped implement her Geodesic Learning™ Theory in a School District in the USA and was able to demonstrate quantitative improvement in scholastics across the board among the students. She is widely published in journal, book, DVD, television and the internet in the field of cognitive neuroscience in South Africa, USA and other parts of the world.
I have discussed neuroscientific subjects with her for multiple hours many times and have been thoroughly impressed with her knowledge and insight in neurobiology. However what really thrills me is revelation God gives her about the brain. She is an example to me of a neuroscientist who glorifies God in her pursuit of understanding the brain, and who is able to demonstrate that we are truly fearfully and wonderfully made (Psalm 139:14).


Since 1985, Dr Caroline Leaf, a Communication Pathologist and Audiologist, has worked in the area of Cognitive Neuroscience. She holds a Bsc Logopaedics with focus on in Neuroscience, Neuronanatomy and anatomy, Communication Pathology, Psychology, linguistics and audiology) , Masters in Communication Pathology She specialized in Traumatic Brain Injury and PhD in Communication Pathology (TBI) and Learning Disabilities focusing specifically on the Science and neuroscience of Thought as it pertains to thinking and learning. She developed a Cognitive Neuroscientific theory called the Geodesic Information Processing Theory for her PhD research and did some of the initial research back in the 1990’s showing how using non-traditional techniques, based on neuroscientific principles of neuroplasticity and neuropsychological principles, that the mind can change the brain and can effect behavioural change as seen academically, behaviorally and emotionally. A large part of her research in recent years has been to link scientific principles with scripture showing how science is catching up with the bible.

She applied the findings of her statistically proven research in clinical practice for nearly 20 years and now lectures and preaches around the world on these topics. She is a prolific author of many books, articles and scientific articles. She has been a featured guest of Enjoying Everyday Life with Joyce Meyer, and LIFE TODAY with James and Betty Robison, Marilyn Hickey, Sid Roth and TBN Doctor to Doctor, amongst many others. She has her own show on TBN called Switch on Your Brain.

Her passion is to help people see the link between science and scripture as a tangible way of controlling their thoughts and emotions, learning how to think and learn and finding their sense of purpose in life.

Caroline and her husband, Mac, live in Dallas, Texas with their four children.

Dr Leaf’s Qualifications

Web page: has my full qualifications and links to the Universities where I studied

Dr Leaf’s Reference list

1. Leaf, C.M. 1985. “Mind Mapping as a Therapeutic Intervention Technique”. Unpublished workshop manual.

2. Leaf, C.M. 1989. “Mind Mapping as a Therapeutic Technique” in Communiphon, South African Speech-Language-Hearing Association, 296, pp. 11-15.

3. Leaf, C.M. 1990. “Teaching Children to Make the Most of Their Minds: Mind Mapping” in Journal for Technical and Vocational Education in South Africa, 121, pp. 11-13.

4. Leaf, C.M. 1990. “Mind Mapping: A Therapeutic Technique for Closed Head Injury”. Masters Dissertation, University of Pretoria.

5. Leaf, C.M. 1992. “Evaluation and Remediation of High School Children’s Problems Using the Mind Mapping Therapeutic Approach” in Remedial Teaching, Unisa, 7/8, September 1992.

6. Leaf, C.M., Uys, I.C. and Louw, B. 1992. “The Mind Mapping Approach(MMA): A Culture and Language-Free Technique” in The South African Journal of Communication Disorders, Vol. 40, pp. 35-43.

7. Leaf, C.M. 1993. “The Mind Mapping Approach (MMA): Open the Door to Your Brain Power; Learn How to Learn” in Transvaal Association of Educators Journal (TAT).

8. Leaf, C.M. 1997. “The Mind Mapping Approach: A Model and Framework for Geodesic Learning”. Unpublished D.Phil Dissertation, University of Pretoria.

9. Leaf, C.M. 1997. “The Development of a Model for Geodesic Learning: The Geodesic Information Processing Model” in The South African Journal of Communication Disorders, Vol. 44, pp. 53-70.

10. Leaf, C.M. 1997. “The Move from Institution Based Rehabilitation (IBR) to Community Based Rehabilitation (CBR): A Paradigm Shift” in Therapy Africa, 1 (1) August 1997, p. 4.

11. Leaf, C.M. 1997. ‘”An Altered Perception of Learning: Geodesic Learning” in Therapy Africa, 1 (2), October 1997, p. 7.

12. Leaf, C.M., Uys, I. and Louw. B., 1997. “The Development of a Model for Geodesic Learning: the Geodesic Information Processing Model” in The South African Journal For Communication Disorders, 44.

13. Leaf, C.M. 1998. “An Altered Perception of Learning: Geodesic Learning: Part 2” in Therapy Africa, 2 (1), January/February 1998, p. 4.

14. Leaf, C.M., Uys, I.C. and Louw, B. 1998. “An Alternative Non-Traditional Approach to Learning: The Metacognitive-Mapping Approach” in The South African Journal of Communication Disorders, 45, pp. 87-102.

15. Leaf. C.M. 2002. Switch on Your Brain with the Metacognitive-Mapping Approach. Truth Publishing.

16. Leaf, C.M. 2005. Switch on Your Brain. Understand Your Unique Intelligence Profile and Maximize Your Potential. Tafelberg, Cape Town, SA

17. Leaf, C.M. 2008. Switch on Your Brain 5 Step Learning Process. Switch on Your Brain USA, Dallas.

18. Leaf, C.M. 2007. Who Switched Off My Brain? Controlling Toxic Thoughts and Emotions. Switch on Your Brain USA, Dallas.

19. Leaf, C.M. 2007. “Who Switched Off My Brain? Controlling Toxic Thoughts and Emotions”. DVD series. Switch on Your Brain, Johannesburg, SA.

20. Leaf, C.M., Copeland M. & Maccaro, J. 2007. “Your Body His temple. God’s Plan for Achieving Emotional Wholeness”. DVD series. Life Outreach International, Dallas.

9 thoughts on “Mac Leaf responds to “Dr Caroline Leaf – Serious Questions, Few Answers”

  1. Pingback: Dr Caroline Leaf – Contradicted by the latest research | Dr C. Edward Pitt

  2. It was really good to hear your arguments around Dr Caroline Leafs work. It proves that the work is worth looking deeper into. She won’t be able to minimise every possible bias. You had some good points and it has helped me to refine how I go about doing my own research and how to present that. Dr Leafs work has been very helpful to me on a personal level, including inspiring me to attempt my own career in psychology and further research into the message that she is trying to convey.
    Any good Dr has peers trying to pull apart their theories, this is the only way humanity will come to any conclusions about how we are wired and how we can function to our full potential.
    Though not everyone gets to go to school/university and do their own research having all this work out simply and in a way that I as a currently uneducated person can understand makes her life work worth more than if it just went into a journal only to be read by peers and pulled apart to try and discover some level of truth.
    Perhaps your approach could be to look at the work she has done and see what benefit it has for “lay” people.
    what are the negative affects of an uneducated person picking up this book switch on your brain and working through it? Why waste time trying to fight against someone’s research and claims ? What are you actually trying to achieve?
    People spend their lives coming up with theories that remain theories, Dr Leaf is using what she knows and the success stories she has seen come to pass to educate others to free their minds.
    I haven’t delved into the percentages from either her or you around illness being related to stress and I am certainly not trying to be scholarly in any way, I just find that seeing someone passionate about people’s health and wellbeing and not cutting parts of their brain out or using medication or electric shocks to treat people much more encouraging and makes the psychology world seem more beneficial than hurting a few people through experimentation only to come to no avail.
    However as previously mentioned it’s great to see that other Drs are paying attention to her work. There must be something worthwhile paying attention to.
    They say research isn’t good research until it’s been picked a part by peers..
    My suggestion to Dr Leaf and her husband would be to note that whatever you’re doing is working because other Drs are paying attention but also maybe it creates opportunity for you to see a different perspective?? Though you are just a couple of people and probably need at least a hundred other researchers to address some of the points he brought up.
    Anyway I’m sitting in a cafe having done no research around any of this, just wanted to say Dr Leaf you’re doing an amazing job and Dr Pitt thanks for picking these points out because it has opened my eyes to narrowing down my own research and working with a smaller group than trying to change the world 😃

    • Jacquie,

      Thanks for your insights and opinions.

      I’m glad that Dr Leafs work (and perhaps my critique) has helped you in finding your path. I wish you all the best in your chosen study and vocation. Psychology helps a lot of people, so I think you’re on to a good thing.

      I can’t speak for Dr and Mr Leaf, but if you feel that Dr Leafs work has benefitted you as a lay person then that’s good. There are many other appreciative testimonies on Dr Leafs social media pages.

      And you’re right in suggesting that any good theory needs to be pulled apart to prove that it’s robust, that’s how good science works. Though it’s interesting to note at this point that Dr Leafs social media moderators actively censor dissenting comment, and block those who express alternative views from commenting. This didn’t just happen to me, but to others who have shared this in comments on this blog. One wonders why Dr Leaf has allowed her moderators to do this, since it only stifles free speech, critical appraisal, and the progress of good science.

      You made a very reasonable suggestion to look at the work Dr Leaf has done and see what benefit it has for “lay” people, and as it turns out, I’ve done so just recently. I reviewed Dr Leaf’s published research including her PhD thesis and a study on the effectiveness of her “Switch On Your Brain 5-Step Learning” module. I think it’s fair to say that Dr Leaf’s published trials have shown that her programs are ineffective. I understand that sounds harsh, so let me clarify.

      In order to eliminate bias, controlled trials with adequate statistical analysis need to be done. When Dr Leafs published results are reviewed in the cold light of day, the change that’s seen is negligible, if indeed there is any change at all. The results in her Dallas study appear to be mostly due to chance. Her PhD research showed negligible difference between the controls and the intervention. There may have also been some negative effects. For a full analysis, I suggest that you review my post “The TEDx Users Guide to Dr Caroline Leaf” (

      You then ask three very important questions: “what are the negative affects of an uneducated person picking up this book switch on your brain and working through it? Why waste time trying to fight against someone’s research and claims? What are you actually trying to achieve?” I am the first to admit that there is no direct evidence that Dr Leaf’s research or teaching has done direct harm, although like I said earlier, Dr Leaf’s moderators suppress dissenting opinion and comment, so who knows. However, if Dr Leaf’s teaching is ineffective, then at the very least, those who have a mental illness and who attempt Dr Leaf’s tools and programs are wasting money and time on something ineffective, when they could be engaging in effective management. Further, in her 2013 book, Dr Leaf suggests that taking anti-depressants for the treatment of depression “is biblically and scientifically incorrect.” (Leaf, C. M. (2013). Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. Grand Rapids, Michigan: Baker Books: p32) Should someone with depression take Dr Leaf’s statement at face value, then there is a real possibility that they would stop their medications and relapse. So Dr Leaf’s teaching may divert someone from receiving useful therapy, and potentially may have serious consequences.

      Hence, why I think that challenging her research and claims is time well spent. Mental health care is critical to our society and the church, which makes it even more imperative that the teaching of the most influential speaker on mental health in the church is critiqued, as her teaching is going shape the direction of the church’s handling of mental health care into the future.

      It may seem esoteric to debate the correctness of statistics, but both the discrepancy between Dr Leaf’s numbers and current estimates, and how she arrived at those numbers, speak to her ability to interpret research and arrive at appropriate conclusions, and thus, how we should judge her other hypotheses.

      If you haven’t done so already, I would suggest that you read my book “Hold that thought: Reappraising the work of Dr Caroline Leaf” (iBooks = or Smashwords = which gives a much more in-depth review of Dr Leaf’s work and the evidence for and against it. I believe that there are a number of critical flaws with Dr Leaf’s teaching, but if you still agree with Dr Leaf after reviewing all of the evidence, then that’s fine. I only ask that people review Dr Leafs work, and my own, with an open mind.

      All the best with your future studies, and again, thanks for sharing your opinion.

  3. I would like just to note that neither mental health care or society has been given the mandate to care for the soul needs. Talk about ineffectual.

  4. I believe strongly in Dr. Caroline Leafs teachings because although I just found her on facebook earlier this year the way she teach I have been learning for years. My brain work the same way as she teaches the brain work. I keep up a continual internal dialog with the Holy Spirit as she teaches and it works to keep your thought life under control. Stop fighting against what she say (being so technical) and try to learn something that can change your life as well as save it. I love you Dr. Caroline, Vanessa

    • Thanks for taking the time to comment Vanessa. Your feelings for Dr Leaf are touching, and your opinions are common amongst Dr Leaf’s ardent supporters.

      It’s not my place to tell you what to believe, that’s entirely up to you. If you want to believe Dr Leaf’s teaching, I’m not going to argue. So long as you can honestly say that you have considered both sides of the debate.

      Dr Leaf is charismatic and engaging, but spinning a good story isn’t necessarily the same as speaking the truth. So perhaps it’s Dr Leaf who should stop fighting what I say and try and learn something from me?

      Like I said, you can believe what you like, but I’m confident that there’s nothing I can learn from Dr Leaf, and I am supremely confident in my salvation as my faith is in God’s word, not Dr Leaf’s version of it.

      All the best to you.

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