Maybe so, according to psychologists studying convicted murderers. In a new study of previously diagnosed psychopaths and non-psychopathic murderers, the researchers were able to discern who are psychopathic by analyzing their word choices:
Psychopaths were far more likely to say they committed the crime because of personal needs, like food and money, and they described their deeds in the past tense, suggesting it happened a long time ago and there was little that the perpetrator could do to prevent it. They seemed emotionally detached from the murder, and as might be expected, they showed no remorse. [...]
The non-psychopathic killers, by contrast, were far more likely to describe their past in terms that reflected social needs, like family, religion and spirituality.
"In the context of a committed murder, it is likely that the non-psychopaths were aware of and affected by the profound effects their crime would have had on their own families and the victim's family," the study says. No such concern was shown among the psychopaths.
The bottom line: "Psychopaths operate on a primitive but rational level," say the researchers.
Previously on Neatorama: Psychologist: Leaders Are Four Times as Likely as the Average Person to Be Psychopaths
Jon Ronson wrote a fascinating book called The Psychopath Test: A Journey Through the Madness Industry that described the very point you brought up.