The Evolutionary Basis of Psychopathy
[Note: I wrote this paper in mid-2010 and deleted it from the internet thinking it might be forever unrecoverable. Well, I managed to find it hidden deep within the recesses of the internet.]
I thought I was pretty original when I figured a few weeks ago that psychopathy could have an evolutionary basis: that there have been selective pressures in favor of genes for psychopathy. I now realize, however, that though literature on the evolutionary basis of psychopathy is scant, the topic has been covered by some academic sources. As someone who lacks a scientific background, I can look at the subject without some of the biases that may be ingrained in students as they are taught about the subject and to apply the scientific method at university. I also lack the ability to test my ideas and the knowledge of the theoretical models such students have. Despite this, I consider myself at an advantage because I can think about such problems from a different vantage point.
For the purpose of expounding on the evolutionary basis of psychopathy, it is necessary to define it: psychopathy is distinguished by an inability to feel empathy for others combined with amoral conduct. So what evidence is there to believe psychopathy is advantageous biologically? Well, actually, psychopathy is not absolutely advantageous, for if everyone were a psychopath life could become somewhat precarious as the society of psychopaths would have no compunction about offing rivals and potential rivals from within. Mass murder could become commonplace, thus enabling up-and-coming peacemakers — or those who can signal peacemaking convincingly — to propagate, as they would be perceived as less of a threat and could actually assist the more flexible psychopathic mass-murderers in surviving and achieving their ends. What we have here is an application of game theory: clearly in the course of human evolution there has been a bias toward peacemakers who genuinely feel and display empathy.
Not only has the ability to empathize — to emotionally feel the pain and anguish of others and to see a situation as others would see it — been positively selected, but it has come to largely define what it is to be human. It is a common feature of humanity to send relief or aid to another continent or the other side of the world when a natural or economic disaster strikes: this is referred to as “humanitarian.” The ability to feel the pain of others is so strong that it even extends to other species, with organizations dedicated to preserving wildlife and that even call for the equal treatment of animals.
As human societies evolved, there was a need for greater order and collaboration within a society. Those who were most able and willing to care for the sick and dying were perceived as a benefit. Individuals indifferent to a neighbor’s life-threatening ordeal have likely existed since the dawn of mankind, but their indifference to the welfare of others was likely to be detected at some point in their lives and to carry its associated negative consequences.  Such persons, generally, were more likely to cheat and steal from others, since they were unable to feel, or care about, another person’s loss. In a primitive society which required order and collaboration, they may have been ostracized or even killed. Clearly, not being able to empathize with others in a tribe which required a communitarian spirit could be a serious liability and thus be negatively selected as a trait (with its associated constellation of genes).
Yet it is estimated that roughly one percent of the world’s population is psychopathic. This is not statistically insignificant. How is it that this one percent has thrived throughout the ages despite the constant threat of being outed as monsters with a human mask and being dealt with accordingly?  I posit that so long as the number of psychopaths is low enough, and their behavior sophisticated enough to fool most people into believing they are normal, as a group they can operate virtually undetected and thus take advantage of the generosity of others without having to contribute to society what is expected of them.
Indeed, if society can be conceived of as a group of people collaborating and competing with each other to amass finite resources, then it could be advantageous for some individuals, low enough in number so that their true intentions remain unnoticed, to take whatever they can from their neighbors, to feign concern for others, and to give when not giving would clearly expose their psychopathic character to others and thus put their neighbors on constant guard. The key for these psychopaths is to take whatever they can and to minimize their contribution in a way that does not arouse suspicion or animosity from others. Psychopaths must therefore apply short- and long-term strategies to achieve their ends, which implies engaging in elaborate schemes to mask their true nature from others.
The skill with which psychopaths are able to mask their true nature varies from one to another. If psychopathy as a trait has had some positive selection, as I posit — that is, so long as the number of psychopaths has been sufficiently low in a society so that they could remain virtually undetected — then over the course of many generations psychopaths would have gotten increasingly adept at blending into the larger society and extracting more resources from it relative to their contributions. If the lesser-skilled psychopaths — those whose lies and deceptions were more easily detected — were punished due to being detected, with ostracism and possibly execution, then those with more sophisticated abilities in the art of deception would have been able to propagate and take their place within this strategic niche.
Finally, there is another mechanism by which psychopaths may have been able to propagate despite the overwhelmingly strong selective pressures for the traits of compassion and empathy. Some recent studies have supported the common observation that women are often attracted to “bad boys,” who include psychopaths unwilling and unable to reciprocate feelings of love.  While getting impregnated by a bad boy carries with it certain risks — such as the bad boy refusing to take care of the child and fleeing to pursue other women — the child sired by a psychopath could have equal or better abilities in seducing and manipulating members of the opposite sex as an adult, thus aiding his (or her) reproductive fitness. So while having sexual partners who are psychopaths is not likely to bring long-term happiness for women, having a child with an inborn talent in the arts of deception and manipulation, with the ability and desire to cultivate such skills throughout his lifetime, could increase their likelihood of having grandchildren and great-grandchildren due to the reproductive success of their offspring.
 In practice, the psychopath may assist others based on his calculation that he may have something to gain from it and not because he genuinely cares about the well-being of others.
 Many members of this group have faced the penalty of death and even excruciating torture throughout the ages. Yet the percent of psychopaths — universally hovering at one percent — implies that for every person ostracized or killed another has had reproductive success to offset the loss.
 Women are not exclusively attracted to “bad boys,” nor are all women necessarily attracted to them. Bad boys happen to have certain traits many women find attractive: they tend to be more assertive, adventurous and detached. For marriage and raising a child, however, many women prefer to have a man who can provide for them and their child. Such men are “providers” and tend to stick around more long term.
[Addendum: I removed second-person references and some wording from this paper since they violate the formal rules of scientific writing, but have decided to keep the first-person references since there appears to be some debate on their utility within science, and since this paper is not meant to be too formal in the first place.]