Complex sentence: The cognitive bias of illusory superiority derives from the metacognitive inability of low-ability persons to recognize their own ineptitude; without such self-awareness they cannot objectively evaluate their actual competence or incompetence.
Split into simpler sentences: The cognitive bias of illusory superiority derives from the metacognitive inability of low-ability persons to recognize their own ineptitude. Without such self-awareness they cannot objectively evaluate their actual competence or incompetence.