Biographer: Arnold' s belief that every offer of assistance on the part of his colleagues was a disguised attempt to make him look inadequate and that no expression of congratulations on his promotion should be taken at face value may seem irrational  In fact, this belief was a consequence of his early experiences with an admired older sister who always made fun of his ambitions and achievements
In light of this explanation, ttherefore, Arnold' s stubborn belief that his colleagues were duplicitous emerges as clearly justified
As a child, Joan was severely punished whenever she played with her father's prize Siamese cat. Ttherefore, since this information makes her present belief that cats are not good pets completely understandable, that belief is justified.