Critics linked her silent and inexpressive personality to alexithymia or a schizoid personality disorder. An official "Death and Rebirth" booklet describes her as "an expressionless noh mask" and "a girl who does not dream", while the book "Schizo Evangelion" as "a dreamless mind, completely separated from Jung's collective unconscious". According to Yoshiyuki Sadamoto, Rei is capable of feeling emotions and feelings but has expressive and communicative difficulties. From the first episodes of the series, Shinji tries to connect with her; however, Rei is unable to parse the meaning of his words and actions adequately. Although the two pilots occasionally converse with each other, they cannot communicate on an emotional level and do not understand their feelings. However, facing a crying Shinji, who is glad that she is alive after a big fight in the sixth episode, she smiles, marking one of her most significant moments of character development. After this, both their words and actions move to a place of mutual understanding. Anno compared her path from the sixth episode onwards, in which there is a step back in her interpersonal communication, to Hideki Gō, a character from the "Return of Ultraman" series; Gō, like Rei, seems to get closer to other people and his colleagues from the Monster Attack Team, only to drift away and become estranged again. For critic Manabu Tsuribe, with the smile of him in the sixth episode "Neon Genesis Evangelion" reaches its climax, and "as a story of 'growth and independence of a boy' — like a Bildungsroman — ended there once. "Evangelion" as a story has stopped there".