The Penny Dropped

It’s the fall of 2019, and the metaphorical penny has finally dropped: I realize that the central claims in psychopathy research just don’t add up.

For nearly seven years, I had been immersed in psychopathy research, trying to wrap my head around the field’s core claims, combing through its sprawling literature. But it wasn’t until late 2019 that I began to see major problems in the field, which ultimately propelled me to write Psychopathy Unmasked.

If there ever was a clear turning point, I think it came through a project I undertook with Stephanie Griffiths and Jarkko Jalava, where we conducted a so-called umbrella review, which we published in 2020 in Psychology, Public Policy, and Law.

If you’re interested, here’s a link to the study: https://psycnet.apa.org/record/2020-35287-001

The goal of our study was straightforward, though the task was anything but. We set out to systematically synthesize all the empirical evidence relevant to three dominant claims about psychopathic individuals in forensic contexts:

1. That psychopathic persons are extraordinarily dangerous

2. That psychopathic persons are incorrigible and untreatable

3. That psychopathic persons are morally impaired in some profound psychological way (e.g., incapable of empathy)

(As I write in Psychopathy Unmasked, there are many more claims [e.g., that psychopathy is correlated with brain abnormalities], but these three claims are arguably the most impactful in the legal system)

As we sifted through empirical studies, it quickly became clear just how little evidence there was to support any of these claims. Even Steph and Jarkko—longtime skeptics—were surprised by how flimsy the foundation really was.

For instance, take the first claim: that psychopathic individuals are extraordinarily dangerous. This is typically measured by comparing recidivism rates between “psychopathic” and “non-psychopathic” offenders.

A typical study goes something like this:

Researchers will (a) enter a correctional institution, (b) recruit a cohort of participants, (c) clinically assess everyone to determine who meets the criteria for the psychopathy group and who belongs in the non-psychopathy control group, and (d) track and compare the two groups’ recidivism rates after their release from prison. In this sense, you get a fairly direct test of the claim about increased dangerousness in the psychopathy-group.

If psychopathic persons truly are the social predators of our society, you’d expect a major difference between these two groups, right?

Sure enough, studies do report statistically significant differences between the two groups—but the magnitude is somewhat trivial (and full of important caveats; I write much more about this in Psychopathy Unmasked).

In fact, when you look at the actual overlap in reconviction rates between the two groups, it’s about 76%. In other words, three-quarters of the time, you can’t tell a “psychopath” from a “non-psychopath” based on how likely they are to reoffend. That hardly supports the notion that the psychopathic group consists of “social predators” while the other does not.

The other two claims were even weaker. We found no reliable evidence to suggest that psychopathic individuals fail to benefit from treatment and rehabilitation programs. And the idea that they are morally compromised in some fundamental way? That claim—echoed endlessly in research articles, textbooks, and expert testimony—has never been grounded in any serious empirical work.

For me, as a junior researcher in 2019, this was nothing short of a jaw-dropping revelation. The problem wasn’t just that the evidence was weak—it was that these three core claims had never been empirically supported, even as they continued to shape high-stakes legal decisions.

I went through graduate school thinking that this kind of cognitive dissonance—the act of believing in an idea despite evidence to the contrary—shouldn’t happen in science. But there it was.

Here we had a powerful forensic label—one that influences legal decisions such as sentencing, civil commitment, parole, and even death penalty cases—resting on little more than a captivating narrative.

After our review came out in 2020, the implications hit me hard:

If the empirical differences between psychopathic and non-psychopathic individuals are minimal… how can the legal system justify treating psychopathic persons so differently?

I spent months thinking hard about this question. But I kept arriving at the same answer: the forensic use of the psychopathy diagnosis is both empirically and ethically unjustifiable.

And with that realization, thefoundationfora book project waslaid… now I “just” had to write it and find a publisher willingtosupport the project.

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This article is part of the series “The Making of Psychopathy Unmasked,” which shares behind-the-scenes stories about how the book came together and the experiences that shaped my thinking on psychopathy. To read more entries in the series, follow my profile or visit https://www.psychopathyunmasked.com/blog