Abstract

In Phillip Kerr’s 1994 spellbinding novel A Philosophical Investigation, the medical test to which the protagonist refers is a functional brain scan based on positron emission tomography. It is used to run large studies of male and female brains and, following a lead suggested by animal studies, has been used to identify rare cases of human male subjects who lack the ventral medial nucleus. This nucleus, in the experiment, is hypothesized to inhibit the activity of the sexually dimorphic nucleus, a preoptic area of the male brain believed to be a repository of male aggressive response. Prior research, we learn from the plot, shows that 3 in 100,000 human males are VMN-negative. Thirty percent of those affected are believed to be in prison or to have a criminal record; 70% are believed to stabilize levels of aggression by producing increased levels of estrogen. Identities of subjects participating in the brain scan studies are protected through the conversion of real names to those of famous figures of the past — Bertrand Russell, Charles Dickens. Those for whom results are unfavorable are recontacted, and they are offered counseling.