CBT is based on a cognitive model of mental illness which Beck proposed. As shown in the example above, the model suggests our emotions are a result of our interpretations of events. Beck put forward three levels of cognition which are core beliefs, dysfunctional assumptions and negative automatic thoughts. Core beliefs seems to be a common issue in patients, an example is Beck's negative triad. This is composed of what seems to be irrational thoughts about the self, the world and the future. This may be evident in patients facing depression. Beck used his model as a starting point to develop CBT so that we can improve our understanding about emotions and behaviour. 