The concept refers to the historical development of cognitive behavioral therapy since its inception. From the very beginning, it was not seen as a comprehensive therapeutic approach, but developed through successive wave-like stages, each of which added new dimensions and more complex methods for understanding, interpreting, and correcting human behavior:
1) The first phase begins with the so-called behavioral wave (first generation), which focused on classical conditioning and operant learning as the main mechanisms of emergence and change Behavior. It relied on such methods as extinction, reinforcement, punishment, systematic development, and environmental control.
2) Then came the second wave (second generation), represented by Albert Ellis and Aaron Beck, where the cognitive dimension was introduced in order to emphasize the role of irrational thoughts, beliefs, and thought patterns in shaping emotions and behaviors. Rational Emotive Behavioral Therapy (REBT) and cognitive therapy have emerged, and the focus has shifted to restructuring and changing mindsets along with behavioral interventions.
3) With further development and research, a third wave (third generation) emerged, embracing more holistic and humanistic approaches such as Acceptance and Responsibility Therapy (ACT), Dialectical Behavior Therapy (DBT), and Mindfulness-Based Therapy (MBT). The idea was not only to change beliefs, but also to increase self-awareness, develop psychological resilience, focus on acceptance rather than constantly fighting negative thoughts, and use context and human relationships in therapy.
As such, these waves or phases represent a continuous, cumulative movement that has made CBT a multidimensional therapeutic approach integrating behavior, cognition, emotion, mindfulness, and acceptance, which has helped it become one of the most influential, pervasive, and effective therapeutic schools in the field of mental health.