Due to the complexity of the human mind, it has various levels of consciousness: the state of dreaming, conscious-rational and lastly the subconscious level. This last level is one which is incapable of logic or reasoning abilities, and cannot differentiate between what is real and what is fictional. As compared to the conscious mind, the subconscious lays dormant most of the time and does not play a part in our daily lives. It is the silent voice within that carry out actions out of habit without logically thinking about it. For example, when we are hungry we automatically look for food in our fridge without thought.

Subliminal messages sent into the subconscious mind provide it with the basis to grow the message into reality. It is a form of controlling your thoughts, as there is a link of communication between the subconscious and the conscious mind, allowing it to affect each other. Hence, there has been much controversy surrounding the usage of these subliminal messages, as hidden persuasive messages have been used to manipulate the audience. This has been especially noted in commercials and advertising, and in rock music. There has been much criticism on the use of insidious subliminal messages to increase profits.

Subliminal messages used in advertising or subliminal advertising, are usually in the form of brief visual or audio messages that your mind does not consciously register what it has seen or heard. There is usually a less than 25% chance that the message will be picked up by the conscious, and is used to provide stimulus for action.

Subliminal advertising does exist. However, very few marketing agencies endeavor to insert such messages due to the powerful impact that they can exert on the audience, which would result in overwhelming negative press that would be received if the subliminal message was detected. This outweighs any potential benefit that the subliminal advertising may bring. Most marketing agencies are unwilling to risk the reputation of their company over such an issue, however some agencies still carry out such projects but with caution and with as little subliminal messages as possible.

According to an April 2006 issue of the New Scientist, research has proven that subliminal advertising messages do work, under the right conditions. The researchers also found that priming only works when the prime is goal-relevant. In plain English, this means you're likely to buy a product that quenches your thirst only if you were already thirsty anyway. Subliminal messages are thus more useful in priming a target audience to choose one brand over another, rather than in creating an actual need for the product.

Whilst it is not yet sufficiently proven that the brief subliminal messages can affect your behavior without your awareness of it, it is still debatable if subliminal advertising can be more effective than normal means of promotional communications which people are consciously aware of. In the meanwhile, subliminal messaging still remains relatively successful in helping the lives of people as we can see through the numerous amounts of good reports on it.