Psychoanalysis has influenced the clinical understanding and research designs of those interested in psychosomatic medicine. From psychoanalysis has come the recognition of unconscious mental functioning and the importance of the early years of life; the study of variation in ego functions; and understanding of the nature of the psychological relation between experimenter and subject. Utilizable techniques derived from psychoanalysis are free association, analytical comprehension of symptom response to psychological data, and projective tests.