Answer:
Regression
Explanation:
Defense mechanism is a denomination given by Freud for the manifestations of the ego in face of the demands of the other psychic instances (Id and Superego). Freud defined that the defense mechanisms were called compensation, atonement, fantasy, reactive formation, identification, isolation, negation, projection, and regression.
Robin, shown in the question above, is using the defense mechanism called regression, which is the process of returning to an earlier stage of development where satisfaction was more immediate or displeasure was less. Robin keeps coming back to the behaviors of his child phase because he believes it was a more comfortable and less stressful phase.