Individuals process information in two ways: Cognitive system (head level information processing) and experiential system (heart-level information processing).
Cognitive system process the intellectual information: things that we can put into words easily and things that requires more analytical thinking (head-level processing). On the other hand, experiential system is closely tied to the emotions that is responsible for processing the cognitive information. This information is harder to convey and is processed in a more holistic, intuitive and preconscious manner (heart-level information processing).
It is believed that the challenge for the psychologists is to ensure that changes in unhelpful beliefs (that can contribute to low self-esteem etc.) occur in both "intellectual" and "emotional" levels. If it does not, then behavioural changes are unlikely to endure and the emotional stress will tend to persist.