There is a common misunderstanding about the nature of the more profound types of manipulators in scientific literature.  As the fields of neuroscience and genetics advance, our ability to see actual differences within the brains of "normal" or average people compared with those who are on the psychopathic end of the spectrum becomes much more clear.  However, the explanations for those differences are still unclear, at least for those who study the more profound manipulators in sterile or controlled settings such as an office or within the tube of an MRI machine. Adding to the mix would be other potential contributing factors such as environment, upbringing, and traumatic experiences, all of which are a part of the "nature vs. nurture" discussion pertaining to contributory influences on behaviors. 

 

However, it is important to note that few, if any, of the current experts or researchers in the field have spent any significant amount of time working clinically "behind bars" with a large enough sample of the most profound criminal manipulators to truly gain sufficient valuable qualitative information, which is derived from interacting with the subjects in such a way as to obtain reliable information from unscripted interactions and observations.  This is normally not possible or practical for the average researcher, as it would take unfettered access within a prison, with 100% access to inmates in both general population and solitary confinement, to conduct the right type of qualitative clinical research over the course of a decade or more, ideally with thousands of incarcerated inmates, to generate reliable results. 

 

But, having had the opportunity necessary to fulfill such criteria, we are able to report that the more profound types of manipulators are neither rare nor impulsive.  Instead, they are quite purposeful, intentional, and skillful.  And, they are more common than we would expect or want to believe.  As such, the more you know about them and how they operate, the more you will be able to protect yourself emotionally and maintain healthy boundaries.