One thing that separates narcissists and psychopaths from the rest of society is their apparent lack of empathy. Read about empathy and personality disorders.
What is Empathy?
Normal people use a variety of abstract concepts and psychological constructs to relate to other persons. Emotions are such modes of inter-relatedness. Narcissists and psychopaths are different. Their "equipment" is lacking. They understand only one language: self-interest. Their inner dialog and private language revolve around the constant measurement of utility. They regard others as mere objects, instruments of gratification, and representations of functions.
This deficiency renders the narcissist and psychopath rigid and socially dysfunctional. They don't bond - they become dependent (on narcissistic supply, on drugs, on adrenaline rushes). They seek pleasure by manipulating their dearest and nearest or even by destroying them, the way a child interacts with his toys. Like autists, they fail to grasp cues: their interlocutor's body language, the subtleties of speech, or social etiquette.
Narcissists and psychopaths lack empathy. It is safe to say that the same applies to patients with other personality disorders, notably the Schizoid, Paranoid, Borderline, Avoidant, and Schizotypal.
Empathy lubricates the wheels of interpersonal relationships. The Encyclopaedia Britannica (1999 edition) defines empathy as:
"The ability to imagine oneself in anther's place and understand the other's feelings, desires, ideas, and actions. It is a term coined in the early 20th century, equivalent to the German EinfÃ¼hlung and modelled on "sympathy." The term is used with special (but not exclusive) reference to aesthetic experience. The most obvious example, perhaps, is that of the actor or singer who genuinely feels the part he is performing. With other works of art, a spectator may, by a kind of introjection, feel himself involved in what he observes or contemplates. The use of empathy is an important part of the counselling technique developed by the American psychologist Carl Rogers."
This is how empathy is defined in "Psychology - An Introduction" (Ninth Edition) by Charles G. Morris, Prentice Hall, 1996:
"Closely related to the ability to read other people's emotions is empathy - the arousal of an emotion in an observer that is a vicarious response to the other person's situation... Empathy depends not only on one's ability to identify someone else's emotions but also on one's capacity to put oneself in the other person's place and to experience an appropriate emotional response. Just as sensitivity to non-verbal cues increases with age, so does empathy: The cognitive and perceptual abilities required for empathy develop only as a child matures... (page 442)
In empathy training, for example, each member of the couple is taught to share inner feelings and to listen to and understand the partner's feelings before responding to them. The empathy technique focuses the couple's attention on feelings and requires that they spend more time listening and less time in rebuttal." (page 576).
Empathy is the cornerstone of morality.
"Empathy and other forms of social awareness are important in the development of a moral sense. Morality embraces a person's beliefs about the appropriateness or goodness of what he does, thinks, or feels... Childhood is ... the time at which moral standards begin to develop in a process that often extends well into adulthood. The American psychologist Lawrence Kohlberg hypothesized that people's development of moral standards passes through stages that can be grouped into three moral levels...
At the third level, that of postconventional moral reasoning, the adult bases his moral standards on principles that he himself has evaluated and that he accepts as inherently valid, regardless of society's opinion. He is aware of the arbitrary, subjective nature of social standards and rules, which he regards as relative rather than absolute in authority.
Thus the bases for justifying moral standards pass from avoidance of punishment to avoidance of adult disapproval and rejection to avoidance of internal guilt and self-recrimination. The person's moral reasoning also moves toward increasingly greater social scope (i.e., including more people and instituhttp://www.healthyplace.com/administrator/index.php?option=com_content§ionid=19&task=edit&cid=12653tions) and greater abstraction (i.e., from reasoning about physical events such as pain or pleasure to reasoning about values, rights, and implicit contracts)."
"... Others have argued that because even rather young children are capable of showing empathy with the pain of others, the inhibition of aggressive behaviour arises from this moral affect rather than from the mere anticipation of punishment. Some scientists have found that children differ in their individual capacity for empathy, and, therefore, some children are more sensitive to moral prohibitions than others.