Are “Psychopaths” Morally Colorblind?

For more than two centuries, scientists and clinicians have described people diagnosed with psychopathy as morally colorblind—as if they possess a psychological defect that prevents them from genuinely comprehending moral values and thus reasoning about moral issues.

If you are vaguely familiar with the concept of psychopathy, I’m sure you have come across this notion in some form or another.

The idea of psychopathy as a condition associated with “moral colorblindness” dates back centuries. The earliest version I have been able to locate is from 1786, when Benjamin Rush described a condition called “anomia” (he later named it “moral derangement”) as a defect in the ability to “distinguish between right and wrong.” Other 19th century thinkers like James Prichard, Jean-Étienne Dominique Esquirol, and Cesare Lombroso echoed similar themes.

However, while the idea was always intriguing to some early psychiatrists, it was probably Hervey Cleckley, in his book The Mask of Sanity (1941), who popularized the moral colorblindness metaphor. According to Cleckley, a psychopath can observe that murder or theft is described as “morally wrong” by other human beings. But just like a colorblind person who knows the words “deep red” and “salmon pink” without perceiving the difference, psychopathic individuals cannot grasp the true reasons why murder or theft is wrong. They simply lack the psychological capability to reason about moral issues, Cleckley argued.

Robert Hare later advanced a similar analogy in his popular 1993 book Without Conscience, comparing psychopathy to a colorblind driver who stops at the top light, not because it’s red, but because he knows the convention that the top light means “stop.” The driver doesn’t know the perceptual quality of the color red. He only knows that other people assign significance to it. Therefore, a psychopathic person has no real ability to reason about a moral issue.

Both Cleckley and Hare claimed that such a person would therefore have little behavioral inclination to respect moral values. Because how could you possibly care about something you have no real understanding of?

Although the moral colorblindness-metaphor is fascinating, most researchers today recognize that it’s deeply problematic. Why? Because to this date, there’s simply no clear scientific evidence that psychopathic individuals suffer from such a profound moral reasoning deficit.

One early study by James Blair in 1995 (n=20) hinted at psychopaths having problems with distinguishing between moral vs. conventional issues (e.g., physical violence vs. social etiquettes). However, this study has since been criticized on various methodological grounds, and subsequent attempts at replicating Blair’s results have failed (oddly, Blair’s study is still being widely cited in some scientific circles, accumulating 59 citations in 2024 alone).

Aside from Blair’s one-hit-wonder study, virtually all attempts at testing psychopathic persons moral reasoning capacities have failed to find robust evidence of moral colorblindness.

Do you want to review the details of this research paradigm? In Psychopathy Unmasked, I review every psychological study ever conducted on moral reasoning in clinically diagnosed psychopathic individuals (a total of 21 such studies + 66 empathy studies).

To me, a couple of important questions still remain unanswered. For example, why has the view of psychopathy as moral colorblindness persisted in science and culture for so long—and why are some researchers still intrigued by this idea despite the lack of evidence?

These are some of the difficult questions I explore in detail in Psychopathy Unmasked.

---

Newsletter – Sign up here