they lack self-control, and the ability to think and feel Most are above average intelligence They are psychologically incomplete human beings, but learn to act as though they are Not all have been sexually or physically abused They are uncontrollably addicted to killing They occur in all societies Serial killing has occurred throughout history Morrison also notes a remarkable lack of substance abuse in serial killers. Insanity defense Morrison argues that most serial killers should not be counted guilty of their crimes by reason of insanity; she contends that they are incapable of understanding the evil of their actions despite being, in many cases, highly functioning individuals in society. She describes the mind of a serial killer as flying through life with large blind spots and missing pieces of what it means to be human, and claims that these people are untreatable because they are missing the parts that need treatment. Morrison's theory of why people become serial killers Morrison disagrees with or downplays theories that attribute serial killing to complex psychological motives such as suffering child abuse, which is not a consistent factor. She contends that serial killers are so lacking in emotional development that they have no capacity for complex emotional motives. The book presents various facts, perceptions and descriptions of serial killers in a diffused way and ties the ideas together at the end while presenting the theory that the origin of a serial killer's behavior is genetic. An illustrative example notes that serial killers experience profound physiological events during their crimes that are related to the hypothalamus and that the serial killer's lack of emotion has a similar connection to the hypothalamus. Morrison also describes how serial killers' crimes are similar to drug addiction. Criticism Neuropsychiatrist Rachael Bell compiled a list of common complaints against Morrison and her theories: Morrison uses "unsubstantiated myths" in her work, most notably in a section where she reviews historical cases of serial killings, such as those of Elizabeth Bathory. Although Morrison claims that serial killers have "irresistible impulses," she is unable to reconcile these impulses with the extremely methodical manner in which they find and dispose of victims. Morrison does not use a large enough sample; Bell commented that she has found no proof that Morrison actually conducted in-depth interviews with 80 killers. An investigative piece written by Cliff Doerkson for the Chicago Reader alleges that Morrison's book is inconsistent