The Psychopath Inside

What is this book about?

James Fallon is a neuroscientist who studies violence and psychopathy. While scanning the brain images of serial killers, he discovered, by chance, that his own scan looked much like theirs. The book grows out of that moment: he describes the shock of the discovery, and uses brain imaging, genetics, and upbringing to explain which factors actually combine to produce an antisocial personality. It is part memoir, part science, and it asks uncomfortable questions about the line between researcher and subject.

Why read it?

What makes it unusual is that narrator and subject are the same person: a scientist who studies psychopathy suddenly finds he has a psychopath's brain. The neuroscience stops being a set of cold cases and gains the honesty of self-examination. You learn what research says about the neurology and genetics of antisocial personality, and you watch a scientist face the awkwardness of his own conclusions.

Core Ideas

• Psychopathy is not caused by one thing: the warrior gene (MAOA), low amygdala function, and childhood abuse work together.
• Having the brain profile of a psychopath does not mean becoming a criminal.
• A caring family environment can switch off the expression of the relevant genes (epigenetics), keeping a person off a criminal path.
• Nature and nurture are not either/or: genes supply a tendency, and environment decides whether it is triggered.

What questions does this book try to answer?

• Are psychopathic killers born or made — and do genes decide whether we turn to crime?
• If someone is born with such a brain and such genes, how much responsibility for his actions can he still bear?

Who should read it?

For readers interested in criminal psychology, neuroscience, and genetics, and for anyone drawn to the nature-versus-nurture debate. The author writes about his own research and himself with unusual candour; it involves violent cases and family history, so it asks for some emotional tolerance.

How to Read It

The one thing to remember from the book: a caring family can switch off the expression of psychopathic genes (epigenetics) and keep a person off a criminal path — genes give a tendency, environment decides whether it fires. While reading, keep "similar brain scan" strictly separate from "will commit crimes"; the author himself stresses the first does not imply the second. The research linking genes such as MAOA to crime is still developing, so treat the book as one researcher's account and hypothesis rather than settled fact.