Final answer:
Alfred Adler is the scholar who studied birth-order and the inferiority complex, but the concept of self-actualization was emphasized by Abraham Maslow, not Adler.
Step-by-step explanation:
The scholar who studied birth-order, inferiority complex, and did not study self-actualization is Alfred Adler. Alfred Adler was a colleague of Sigmund Freud and significantly contributed to the development of psychology with his school of individual psychology. Adler introduced the concept of the inferiority complex, suggesting that a person's feelings that they lack worth are what drive people to strive for superiority.
Adler also theorized about the psychological impact of one's birth order on their personality, proposing that older siblings might become overachievers to compensate for shared parental attention, and the youngest could be spoiled, leaving the middle child to balance out these dynamics.