Final answer:
Alfred Adler is a neo-Freudian theorist who emphasized the influence of feelings of inferiority on personality development.
Step-by-step explanation:
The neo-Freudian theorist who emphasized that personality development is strongly influenced by feelings of inferiority is Alfred Adler. Adler proposed the concept of the inferiority complex, which is the idea that individuals have feelings of lacking worth and not measuring up to the standards of others or society. These feelings of inferiority drive people to strive for superiority, influencing their thoughts, emotions, and behaviors. Adler's theory is a critical deviation from Freud's emphasis on sexual and aggressive urges, focusing instead on the role of social factors in personality development.