Final answer:
Client-centered psychotherapy, developed by Carl Rogers, emerged in the 1950s and marked a move towards humanistic psychotherapy, focusing on empathy, unconditional positive regard, and genuineness. At the same time, behavior modification therapies were misguidedly used to 'cure' homosexuality.
Step-by-step explanation:
The therapy that began emerging in the 1950s was client-centered psychotherapy, developed by Carl Rogers. This therapy, also known as person-centered therapy, is founded on the principle that an individual has within themselves vast resources for self-understanding and for altering their self-concept, attitudes, and self-directed behavior. Rogers believed that these resources could be tapped if a definable climate of facilitative psychological attitudes were provided. Beyond the development of client-centered therapy, the 1950s also saw the unfortunate rise in popularity of behavior modification therapy which was aimed at 'curing' individuals of homosexuality, a practice that was both unethical and harmful.
The introduction of client-centered psychotherapy marked a significant shift in the mental health field, moving away from more directive and diagnosis-focused approaches. The principles of this therapy emphasize empathy, unconditional positive regard, and genuineness from the therapist towards the client. This approach aligns with a movement towards more humanistic methods of psychotherapy and a departure from more traditional psychoanalytic techniques.