circuits that may drive sensation seeking, along with smaller frontal lobe circuits that may minimize their sensitivity to punishment and the capacity for self-control, these differences are statistical. What “statistical” means is that if you were to stack up all of the brains with hyperactive dopamine circuits and smaller frontal lobes into one pile, most, but not all would be from psychopaths. You would also find psychopaths in the pile of brains showing normal dopamine activity and average-sized frontal lobes. These brain differences are interesting, but they are not yet like fingerprints, absolutely and uniquely distinctive and diagnostic of a disorder. Such honesty reveals the challenges we face in answering the simple question What’s normal? Lawyers, judges and juries face the same problem as clinicians, often relying upon documents such as the DSM to determine when someone has acted outside the range of normal behavior. But for legal cases, there are two relevant layers of the normalcy problem. The first concerns whether the supposed criminal was sane or insane. An insanity defense requires evidence of a disease or defect of the mind. It requires evidence that the individual lacked the capacity to appreciate the criminal nature of the act as well as the capacity to conform. This is the part that relies on the DSM, as well as clinicians who can testify based on their expertise. The second concerns a more general understanding of what a prototypical or normal human would or could do in a given situation. The idea seems straightforward enough, but as I mentioned above, is only deceptively straightforward. Crimes of passion provide a useful illustration of the challenges we face, especially with respect to understanding how harm is ignited in the face of moral norms against it. Highlighting the truism that love makes you crazy, the crime of passion defense is invoked for cases where, in the heat of the moment, an individual finds and kills his or her spouse in