Final answer:
Rudolf Dreikurs popularized the Adlerian approach in the United States, which focuses on social environment and striving for significance.
Step-by-step explanation:
Rudolf Dreikurs is credited with popularizing the Adlerian approach in the United States. This approach, created by Alfred Adler, is distinct from Freudian, Jungian, and Skinnerian approaches in that it emphasizes the importance of social environment and culture on personality. The Adlerian approach deviates from Freud's views by focusing less on sexual tensions and more on the individual's sense of community and their striving for significance and superiority, which can often manifest as an inferiority complex. Dreikurs applied Adler's theories to education and therapy, promoting an understanding of individual behaviour within the context of social dynamics and personal goals.