Is human behavior determined by the conscious mind?

There are also subconscious and unconscious, as Freud said. Xu Longguang, a master of psychological anthropology, also added that part of one's social culture (i.e., the external world on which one is strongly dependent) and part of one's useful social culture (i.e., the external world on which one forms role interactions with oneself and does not have a strong emotional dependence) are also part of personality (you can read Mr. Xu Longguang's "Culture and Self"). This view places human behavior in a socio-cultural context (see Mr. Xu Longguang's Culture and the Self).

Marxist theory also does not say that consciousness determines behavior, and argues that this view is idealistic because behavior is, for example, conditioned by a material base.

Also, behavior is learned and herd-like, and these do come from one's own consciousness at a superficial level, but at a deeper level, from the moistening and socialization of the community. So your view is too superficial~