Final answer:
The third principle of Motivational Interviewing is 'Encourage collaboration,' which is essential for fostering metacognition and critical reflection by promoting an atmosphere of respectful partnership between counselor and client.
Step-by-step explanation:
The third principle of Motivational Interviewing (MI) is Encourage collaboration. This involves fostering an atmosphere of partnership and mutual respect between the counselor and the client. Encouraging collaboration is vital for improving metacognition and critical reflection, as it enables self-aware and conscious effortful attention which can initially feel unnatural and tiring. By engaging in collaborative activities, clients can better understand their own thought processes and feelings, thereby enhancing their critical reflection and their ability to manage cognitive biases. To implement this principle, counselors should avoid being prescriptive and instead work with the client to explore and resolve ambivalence, promoting a sense of agency and ownership over one's decisions and actions.