I’ve written about two men from the same family who separately became serial killers, Danny and Larry Ranes. Larry, the youngest brother by a year and a half, killed five men over two months in 1964. Once caught, he confessed to them all. Eight years later, Danny raped and killed four women, three of them with a teenage accomplice. He insisted he was innocent but got convicted. Although Danny thought Larry exaggerated their father’s brutality, both recalled his unpredictable behavior, random abuse, arbitrary punishments, and paternal indifference. He abandoned the family when they were 9 and 10, leaving his wife to raise four kids (the other two were girls). In court, the oldest sister acknowledged that their early home life had been chaotic and lacking in moral guidance.

I have long believed that the father’s erratic behavior, coupled with the mother’s passivity, had influenced their sons’ later antisocial behavior. Larry developed a persona of callous indifference, coming across as a sociopath to a professor who interviewed him in prison. The same professor thought Danny wasn’t as bad, but his coercion of a teenage boy into rape and murder was highly manipulative and the crimes were more brutal and predatory than Larry’s string of robbery-homicides. Both brothers had been impulsive, Larry worse than Danny.

Recent research validated my sense of the influence of an unstable household on the development of criminality. By no means can we generalize from a single family’s circumstances or attribute cause and effect from one study, but the research adds a suggestive piece of the puzzle.

Instability and Secondary Psychopathy

Psychologist Virgil Zeigler-Hill and his colleagues found a significant degree of correlation between an unpredictable home life and the impulsivity and lack of empathy seen in kids at risk for developing psychopathy—especially for males. The lack of consistency seems to undermine their ability to form goals and develop prosocial commitments. In the Ranes case, both brothers dropped out of high school. Their marriages (two each) were short-lived, including the one each had with the same woman. (A prison psychologist told Danny’s first wife that due to the chaos of his upbringing, he might not know how to love.) Both took risks with their crimes and showed indifference to the harm they caused.

Genetic factors influence the development of psychopathy, so it’s possible that the brothers inherited an antisocial predisposition. No brain scans or genetic workups were ever done on them. Since environmental factors can exacerbate the genetic factors, the chaotic household might still be important. In other words, brain abnormalities might yield a “born” or primary psychopath, but the environment might “make” a child prone to developing psychopathic traits. Some researchers call this secondary psychopathy. Kids adjust to the anxiety caused from adverse circumstances by becoming callous or impulsive. They can’t plan for long-term rewards because they can’t predict what’s coming next, and they struggle to manage their hostility.

The researchers in this study used the triarchic model of psychopathy in order to measure the effect of both harsh circumstances and instability on each of the three dimensions. “Previous research has often treated both childhood adversity and psychopathy as broad, unitary constructs,” said Zeigler-Hill to Science Direct. “We wanted to distinguish between childhood harshness and unpredictability while examining three components of psychopathy: meanness, disinhibition, and boldness. This allowed us to ask which features of childhood environments were associated with which adult personality traits and whether those patterns differed between men and women.”

Data came from three groups (American and Israeli community members and American college students), yielding 4,873 subjects, about 60% of which were female. More than half received some form of compensation. Each participant completed the Perceived Childhood Harshness and Unpredictability Scale and the Triarchic Psychopathy Measure.

Perceived childhood unpredictability was positively associated with both meanness and disinhibition but not with boldness. Male participants who remembered highly erratic childhoods reported more incidents of being callous, exploitative, and reckless.

“The findings underscore the importance of treating psychopathy as multidimensional because meanness, disinhibition, and boldness showed different patterns of association with childhood conditions,” Zeigler-Hill said. “They also illustrate why a difficult childhood should not automatically be equated with an unpredictable one.” A stable home with few resources might have a more beneficial influence than a resource-rich but chaotic home.

The researchers don’t conclude that unpredictability causes reactive psychopathy. They also acknowledge that the questionnaire about early memories didn’t include physical violence, which could make a difference in the findings.

The Element of Perception in Childhood Instability

I liked that this research focused on perceived childhood unpredictability, as children can process their environment in their own unique ways. Larry, the younger and physically smaller brother, seethed over the way their father used forced competitions to set him up to fail. Danny viewed the same contests as a way to establish his superiority. Their acquired sibling hostility lasted for decades beyond the father’s departure.

Psychopathy Essential Reads

We can’t eliminate a genetic influence in this family, but with three of the four kids describing parental unpredictability and both boys acting out with extreme violence, I think this environmental association needs more attention.