According to Dr. Martha Stout, author of The Sociopath Next Door, a now estimated 4% of the population in America may fall into the category of sociopath. Studies have shown that sociopathy is more than just the absence of conscience. It involves an inability to process emotional experiences including caring and loving, except when such an experience can be calculated as a coldly intellectual tasks. The sociopathic brain responds to emotionally charged words no differently from neutral words, which is unlike the non-sociopathic population. Moreover, single photon emission computed tomography showed increased blood flow to the temporal lobes when the sociopathic brain was given a decisional task that involved emotional words. Such a task would be almost neurologically instantaneous for normal brains. The sociopathic brains were functions as if they had been asked to work out an algebra problem. The research concluded that sociopathy involves an altered level of processing of emotional stimuli at the level of the cerebral cortex—as compared to non-sociopathic brains—although the reason for this is not yet clear. It is possible that this may be the result of a heritable neurodevelopmental difference that can be slightly compensated for, or made worse, by cultural, environmental, or child-rearing factors. This potential certainly shines a new light on the importance of healthy, functional, parenting.