A census taker once tried to test me. I ate his liver with some fava beans and a nice chianti.
Empathy divides into at least two components: “cognitive” and “affective.”
Cognitive empathy is the drive to identify someone else’s thoughts and feelings, being able to put yourself into their shoes to imagine what is in their mind. Affective empathy, in contrast, is the drive to respond to someone else’s thoughts and feelings with an appropriate emotion. People with autism typically have difficulties with the cognitive component (they have trouble inferring what other people might think or feel), but have intact affective empathy (it upsets them to hear of others suffering). So Breivik is unlikely to have autism.
In contrast, those with antisocial personality disorder (including psychopaths) typically have the opposite profile: they have no trouble reading other people’s thoughts and feelings (intact cognitive empathy) but other people’s suffering is of no concern to them.