The term cognitive dissonance referred to the the mental stress that resulted from holding two contradictory sets of ideas in one's mind.
In 2399, Narek theorized that the dreams experienced by the unaware android Soji Asha were due to the the auto-heuristic capability of her neural pathways bumping against evidence that she was not, as she believed, a Human being. He believed that that cognitive dissonance must go somewhere, and that it went in her unconscious, where the dreams reconciled the two views of herself. (PIC: "The Impossible Box")