Question

adlers theory stimulated hundreds of studies on the effect of
generally failed to find support for their hypotheses, more recent family environment studies
focusing on the big five traits have found some support.
self - actualization
reinforcement histories
birth order
primary processes

Explanation:

Adler's theory in psychology often focuses on factors like birth - order, etc. The Big Five traits are a well - known model in personality psychology. Adler's hypotheses generally did not find strong support compared to more recent research on the Big Five. Among the options, birth order is a key concept in Adler's theory.

Answer:

birth order