I argue that emotional sensitivity (or insensitivity) has a marked negative influence on ethical perception. Diminished capacities of ethical perception, in turn, mitigate what we are morally responsible for while lack of such capacities may altogether eradicate responsibility. Impairment in ethical perception affects responsibility by affecting either recognition of or reactivity to moral reasons. It follows that emotional insensitivity (together with its attendant impairment in ethical perception) bears saliently on moral responsibility. Since one distinguishing mark of the psychopath is emotional insensitivity, emotional insensitivity and the resulting impairment in moral perception either excuses the psychopath from moral culpability or moderates the degree to which he is culpable.