Psychopathy: Continuous or Categorical?
I've been thinking about the "continuous vs categorical" debate in relation to psychopathy. I just started reading a book called "Thinking about Psychopaths and Psychopathy" edited by Ellsworth Lapham Fersch. It's a collection of questions and answers from seminars he's given on psychopathy, with contributions by various academics. Based on Fersch's introduction, it looks is promising and insightful. However, I wonder if Fersch really "gets it". While he talks about the importance of psychopathy quite eloquently and identifies the problems inherent in the conflation of psychopathy with antisocial personality disorder, there is a question and answer in the first chapter that is puzzling. (It is possible one of his colleagues answered this question, as the individual author is not listed for each section.)
In this question on the debate between psychopathy as either categorical (i.e. you either have it or you don't, like Turner's syndrome) or continuous (the extreme end of traits shared by everyone, e.g. someone with very high intelligence), he firmly takes the "continuous" side. However, I get the impression that he does so without understanding the crux of the matter, the implications of such a position.
He concludes that psychopathy is continuous because the PCL-R gives results on a spectrum (0 being "least psychopathic", 40 being "most psychopathic"), and because people can score low on the checklist (and thus, technically, have "psychopathic" traits), that people are only "more or less" psychopathic. In other words, because non-psychopaths can score more than 0 on the test and not be considered psychopaths, Fersch concludes that psychopaths only have extreme degrees of more or less "normal" human traits.
I think he is correct, but not for the reasons he would argue, because his argument is fairly weak and susceptible to distortion. First of all, the fact that the PCL-R measures a spectrum of traits does NOT mean that it is measuring a disorder which is itself a "spectrum". The fact that there is no definite "cut off point" on the scale does NOT mean that psychopathy is not categorical. It could just as well mean that we do not yet have the means of identifying an exact cut off point, or that there could be two distinct taxons (normal and psychopathic) that can overlap on the scale.
It is also possible that psychopathy is both categorical and continuous, i.e. that a person is either a psychopath or not, and that those who are psychopaths show a spectrum of indicators of psychopathy (theoretically, all psychopaths would have a majority, perhaps all, of the traits listed in the PCL-R, but they may not be detectable by known personal history and interview).
A thought experiment will make this clearer. Imagine that scientists create a robotic human with artificial intelligence, which will then be tested using a variation on the Turing test, which we will call the "human" test. Questions are asked to the robot based on a checklist of human traits. A normal human, responding to the test, will receive a score of 30 to 40, while primitive forms of AI will receive a low score. Severely mentally ill people may score in the mid-range.
Let us say that our new robot scores 26. It would be fallacious to say that, because the test is continuous, that this implies that the robot is "more or less" human. All it shows is that it shares traits with a human, and these traits may be mere programs. They are algorithms, not experiences with syntactical content. They only give the appearance of humanity.
In this example, one is either a human or not. A human will score mid- to high-range on on the scale, depending on various factors. A non-human will score low- to mid-range. In addition to this categorical difference (human or not), there is a spectrum of how "close" to human a non-human can test. Some robots will test 0 on the scale, while those with complex programming may score fairly high. However, this just shows the limits of the method of testing. Conclusions about the nature of the phenomenon cannot be discerned from measurements of a limited test.
So how do we account for seemingly psychopathic traits in non-psychopaths? I think this can be explained fairly easily. Lobaczewski describes psychopathy as a deficit, NOT an excess. That is, psychopathy is a LACK of certain essential human qualities, and this lack gives rise to the peculiarities of psychopathy. In the case of psychopathy, this lack is syntonic (social) emotions: those responsible for bonding and empathy. Because of this lack, psychopaths see people as objects and a lifestyle develops that makes use of these objects (parasitic, manipulative). Lacking "other-centered" emotions, psychopaths are wholly self-centered (traits which normal humans DO possess, in varying strengths when compared to their other-centered emotions), and thus grandiose, not able to take responsibility. They are unable to feel guilt.
The LACK is what categorically makes them psychopaths, the cause which gives rise to their psychopathic traits WHICH NORMAL HUMANS CAN SHARE. Dabrowski, a contemporary of Lobaczewski, and his concept of multilevelness of emotional functions, provides the necessary context. Normal humanity DOES exist on a spectrum. Many exist with a low level of emotional development, what Dabrowski called primary integration, thus they can be extremely self-centered and even possess many psychopathic traits. As such, normal people can have very poorly developed "other-centered" emotions (and thus the possibility to develop them), the difference being that psychopaths LACK these emotions.
It is also possible that non-psychopathic individuals can originally have such a potential for growth, yet at some point in their lives acquire brain damage that severely alters their emotions and behavior. They can also "learn" psychopathic behaviors. These people may even achieve the same score on the PCL-R as a real psychopath, but people like Fersch don't seem to see this possibility: that the PCL-R is not a perfect measure of psychopathy. It is very effective, but it is not 100% accurate. So the fact that the scale is continuous does NOT imply that the disorder is continuous.
That said, it seems that other factors may be responsible for the continuity WITHIN psychopathy, for example, hippocampus size. Successful psychopaths are perhaps just better at masking their traits, so that an interview and personal history would not necessarily reveal these traits. If we had omniscience, perhaps we would be able to make an accurate diagnosis for these cases, but a mid-range PCL-R score does not necessarily mean that a person is not psychopathic. It could simply be the result of insufficient data.
So it is important to make a distinction between the continuous nature of the PCL-R as an instrument of measurement, and and the nature of psychopathy as a categorical disorder, or taxon. To ignore this distinction is dangerous. As Lobaczewski related from his experience in Poland, pathocratic authorities muddy the waters of psychopathy research so as to evade detection. They do this by creating a "catch-all" phrase for criminal deviance. We have seen this phenomenon in American psychiatry where the official DSM-IV only recognizes "antisocial personality disorder", a catchall label that can apply to both psychopaths and non-psychpoaths. Psychopathy is NOT included in the DSM-IV, and is thus not officially recognized as a valid personality disorder by the Manual.
This might have been enough in pathocracies such as in the Soviet empire, thus providing "cover" for psychopaths who do not fit the diagnosis of "antisocial personality disorder". However, the concept of psychopathy, thanks to Cleckley and Hare, seems too well established in the scientific literature to be so easily embargoed. Thus, a new tactic was needed. Viewing psychopathy as simply an "extreme" form of normality robs us of any real understanding of the disorder.
The entire makeup of a psychopath is qualitatively different from a normal human: their thinking, their worldview, their behavior. It is this "otherness" that is responsible for their dreams of Empire and world domination. By bracketing the true nature of psychopathy from our awareness, we give up any hope of identifying the root cause of the social disease which threatens to choke humanity's life in the near future.