In the two Star Trek series, What would it be like to be able to make decisions on a largely, or even purely, logical basis? Not widely known is that this is a question with an answer based on evidence.

Because of tumors, surgery, and accidents, some unfortunate individuals lose all or most of their ability to make decisions based on emotion. Particularly striking are patients with ventromedial (VM) damage. Patients after VM damage seem to function normally. Their IQ is not impaired, and is sometimes above average. VM patients also do well…