The answer lies in what is known of the conscious, unconscious and the presconscious parts of the mind, with preconscious is the scientific name for the subconscious, however, for the purposes of this answer and because of how the theory of hypnosis is put together, I will refer to the preconscious as the subconscious.
When I was learning about the basis of hypnosis in formal training, I was taught to visualise the mind as the following diagram

Image: CCF diagram from my training notes - the "memories and belief system" part of the diagram is the subconscious part of the mind. The CCF (the orange part of the diagram) is the filter between the conscious and subconscious parts of the brain. It compares a new situation with our memories, belief system and morals.
Formation of our beliefs and morals
Internal and external influences form our belief system which is stored in our subconscious mind. External influences involve things within our environment. Internal influences involve things we ‘know’ to be true. I said ‘know’ because what we believe to be true and what is actually true, correlates with the things we have learnt during our lives. Our belief systems are built from the moment we are born. Our external influences such as what we have seen, touched, tasted, smelt and heard, help us to learn things whilst a baby. Listening to words and speech patterns from our parents help us to learn our language including names for objects.
As we get older and start to be able to wander around and explore our environment our parents tell us things such as “Don’t touch that it’s hot” or “Don’t eat that or you will be ill”. We were told that the grass is green and the sky is blue. Cultural influences start playing a role too such as the idea that pink is a girls colour and blue is for boys, Barbie dolls are for girls and action men are for boys. We took those ideas on as literal truth.
As we got older, experiences begin to confirm some of those ideas. Some got hurt by the heat of a cup of tea. Some got ill from trying the berries we were told not to eat. In these ways we had a model of the world confirmed and constructed.
Some of those beliefs were absolutely correct, we tested the ideas and had them confirmed by outside sources. Some beliefs may have been left untested but nevertheless all the beliefs in turn developed what many call the, Conscious Critical Faculty (CCF) (Watts, n.d.).
The CCF (the orange part of the diagram) is the filter between the conscious and subconscious parts of the brain. It compares a new situation with our memories and belief system and morals. Everything stored in the subconscious is essential for your survival. If the CCF encounters something which goes against the belief systems or morals, stored in the subconscious, it throws the idea out and the belief systems remains intact and life can continue.
But what if there are falsehoods stored in the belief system? Phobias can develop and other damaging effects can take place. This part of the belief system can be built by other people who are unfortunately basing their information on their own belief systems. These in turn were given to them by people who formed their own belief systems. What can we do about this?
Take a situation where comments from adults, taught someone when they are a child, that they are selfish, unattractive or lacking intelligence. Once these ideas have taken hold it is very difficult to try and change these beliefs at a conscious level and remove them from the subconscious mind as the CCF will take over and reject opposing beliefs. This can be damaging to the confidence and opportunities in that persons adult life. This is why it’s so easy to give advice but so difficult for some others to take it even when you know it is correct. For a more effective way of doing this, we need to bypass the Conscious Critical Faculty in order for the correct belief system to be accepted.
There are a number of ways that new information can be pushed past the CCF. (Burns, 2009)
They include:
- Repetition
- Shock
- Hypnosis
Repetition
Selfishness and altruism, attractiveness and unattractiveness, intelligence and lack of intelligence etc. taught as a child or later instilled in adult life is often a result of repetitive comments. The same goes for trust and distrust in certain people or animals. How this happens is for example:-
- A belief that no man can be trusted is put to you on a repetitive basis
- This is usually backed up by other people’s actions. Maybe a man disappointed you in the past
- The concept or belief becomes part of your belief system because no one in your circle of friends can give you an opposing concept or belief to compare it to
- This in turn affects the way you act towards men
- This then causes some men to react in a way which can be perceived to reinforce your belief
Repetitive affirmations and confirmations over time can rectify falsehoods in belief systems.
Shock
Shock that someone may experience as a result of a traffic accident for example, can induce unhesitating acceptance of thoughts and beliefs. (Burns, 2009) If the thought is given where someone says “that looks bad, I bet that hurts” then of course they will become extremely aware of the pain and in turn may develop a severe aversion to getting into a car again. Other traumas can have similar effects.
If you look at someone suffering from the trauma of war, rape or sexual assault, this trauma will lodge the memory of what happened straight in the subconscious and develop either conflicting belief systems which cause more problems, or immediately alter the belief system completely. Counselling sessions can dredge up those painful memories and the resulting shock induced can open the client to opposing thoughts and beliefs which can help to correct the faulty belief system.
Hypnosis
Hypnosis is a natural state of mind where acceptable selective thinking is established, concentration is enhanced and the Conscious Critical Factor is bypassed, opening the subconscious mind to suggestion. With the subconscious mind open to suggestion without interference by the CCF, therapy will be able to work more quickly (Watts, n.d.) by installing correcting belief systems.
The hypnotic state can be induced by reading, carrying out a repetitive task or listening to a hypnotherapist’s hypnotic induction routine. Watching television can induce a hypnotic state which helps to explain how effective on-screen advertising can be.
References
Burns, J., 2009. Beating the barriers to making life changes. [Online]
Available at: http://www.somersethypnotherapy.com/articles-by-John-Burns/beating-barriers-to-change.pdf
Watts, T., n.d. *The Conscious Critical Faculty. [Online]
Available at: http://www.selfhypnosis.com/the-conscious-critical-faculty