Shawn experienced deep depression at the start of his psychotherapy, but his mood significantly improved over time. Which factor is most reasonably credited for part of his progress?

Explanation

The correct answer is regression toward the mean, which refers to the natural tendency for extreme emotional states, like severe depression, to become less extreme over time. This statistical phenomenon can contribute to perceived improvement independent of specific therapeutic techniques. Therapeutic touch involves physical contact, the double-blind technique is a research method to prevent bias, and transference is the patient's emotional projection onto the therapist, none of which directly explain this natural improvement.