impairment, a volume deduction and poor functioning in a part of the brain called the amygdala, the seat of emotion. we have been finding on psychopathic offenders they have an 18% reduction in the volume in the amygdala. when they contemplate making moral decisions like should i kill someone or not, that part of the brain is just not as active as in normal people. >> you have done a terrific job making the science accessible for people. i want to show a couple of images that will be important. you should read the book. take a look there at a scan of the brain, a p.e.t. scan. normal on the left and a murderer on the right. what are we looking at there? >> we are looking down on the brain. this is a p.e.t. scan looking at brain functioning. the red and yellow indicate high glucose metabolism or high brain