But now, a study published in Nature (advance online publication 21 March 2007), "Damage to the prefrontal cortex increases utilitarian moral judgements" presents a strong case that brain damge may be the answer.
... Here we show that six patients with focal bilateral damage to the ventromedial prefrontal cortex (VMPC), a brain region necessary for the normal generation of emotions and, in particular, social emotions ... produce an abnormally 'utilitarian' pattern of judgements on moral dilemmas that pit compelling considerations of aggregate welfare against highly emotionally aversive behaviours (for example, having to sacrifice one person's life to save a number of other lives).... In contrast, the VMPC patients' judgements were normal in other classes of moral dilemmas. These findings indicate that, for a selective set of moral dilemmas, the VMPC is critical for normal judgements of right and wrong. The findings support a necessary role for emotion in the generation of those judgements.Vivisectors defend their activities with the abnormal utilitatian claim that human illness necessitates endless animal experiments regardless of the actual outcome.
The hypothesis that vivisectors have sustained focal bilateral damage to the ventromedial prefrontal cortex (VMPC), or are suffering from a birth defect of the VMPC is testable. All vivisectors should immediately volunteer for screening and possible diagnosis.