According to erikson, children have and thus believe that they can achieve any goal.

According to Erickson, children have "an unrealistic self-concept", and thus believe that they can achieve any goal.
Erik Erikson who was born in 1950 proposed a psychoanalytic hypothesis of psychosocial advancement including eight phases from early stages to adulthood. Amid each stage, the individual encounters a psychosocial crisis which could have a constructive or contrary result for personality development.

answer; triadic reciprocal determinism;

answer; all over the above; //everybody