Final answer:
The perspective in psychology that focuses on self-actualization, unconditional positive regard, and is known as the "third-force" is Humanistic psychology.
Step-by-step explanation:
The perspective that focuses on self-actualization, unconditional positive regard, and is often referred to as the "third-force" in psychology is Humanistic psychology. This approach emerged in the mid-20th century as a response to the perceived limitations of psychoanalysis and behaviorism. Pioneers of humanistic psychology such as Abraham Maslow and Carl Rogers emphasized the human potential for growth, the importance of self-actualization, and the individual's inherent worth. Humanistic psychologists believe that every person has a natural tendency towards becoming their best self and that this growth process can be facilitated through an environment that offers unconditional positive regard.