One theory is that these are people who do not recognize danger as such when it confronts them, thus their heart rates do not speed up. Another theory is that these people experience under-arousal:
Having a low heart rate can be uncomfortable. It kind of feels like boredom. To relieve that, some people seek stimulation through aggression.Yet another theory is that some people experiencing the chronic stress that leads to bad behavior may also adapt via a lower heart rate.
Lead researcher Adrian Raine agrees LRHR is far from the sole determinant of misbehavior.
His review of the research indicates that the trait accounts for about five per cent of all antisocial behavior (and that the rest can be explained by social and biological factors such as upbringing, neighborhood, education, income level, brain chemistry and structure, and so on). L.R.H.R. should be seen, Raine says, as a potential warning sign rather than a definitive mark of inevitable criminality.
