Limited guilt, lack of remorse and empathy, and coldhearted interpersonal behavior characterize what are known as callous-unemotional traits. New research published in the International Journal of Psychophysiology found certain cardiac markers such as resting heart rate and heart rate variability are linked to callous-unemotional traits in juvenile offenders, but not adult offenders.
People who possess callous-unemotional traits tend to exhibit severe antisocial behavior (i.e., behavior that harms other people), earlier onset of delinquency, and an increased likelihood of committing future offenses. Antisocial behavior is also associated with a low resting heart rate. One theory proposes that an individual with an extremely low baseline heart rate (compared to average) may seek excessive stimulation which results in antisocial behavior (e.g., provoking a fight).
Heart rate variability might also be related to antisocial behavior. “In a resting position, higher [heart rate variability] is indicative of successful self-regulation and cognitive control, which allows for flexible and quick responding to environmental needs,” wrote study author Hanne M. Duindam and colleagues.
“Studies have demonstrated that those with higher [heart rate variability] are more successful socioemotionally, such as, in establishing relationships of mutual understanding and engaging in cooperative behaviors.”
Thus, considering callous-unemotional traits are characterized by reduced socioemotional functioning (i.e., lack of empathy and remorse), it could be the case that a lower heart rate variability is associated with these traits. Overall, it is unclear the extent to which resting heart rate and heart rate variability can be used a physiological marker of callous-unemotional traits.
To address this, researchers collected data from 190 male detainees who were part of an ongoing dog training program at certain correctional facilities in the Netherlands. Assessments were done in a private room by one or two trained research assistants. Researchers monitored cardiac activity for all participants during the whole assessment. Participants were assessed for callous-unemotional traits using a validated self-report scale.
Researchers measured several other variables that could be related to heart rate and callous-unemotional traits such as physical activity, smoking habits, caffeine intake, medication and drug use, and respiration frequency. They also collected demographic information such as ethnicity and age.
Researchers split the sample into juvenile and adult offenders to account for the influence of development. Results show that resting heart rate is positively associated with callous-unemotional traits, but only in juveniles. In other words, juveniles who had higher levels of callous-unemotional traits also tended to have high resting heart rates. This pattern was not observed for adult offenders.
Similarly, heart rate variability was negatively associated with callous-unemotional traits in juveniles only. Put other way, higher heart rate variability in juveniles was associated lower callous-unemotional trait scores. These variables were unrelated for the adults.
Overall, results suggest general impairment of autonomic cardiac activity (i.e., higher resting heart rate, lower heart rate variability) is associated with callous-unemotional traits in juveniles, not adult offenders.
“It is unclear to what extent the current null results differ from previous adult research due to diverging design choices (e.g., use of different assessment methods to measure [callous-unemotional traits], sample make-up) – or because the relationship between cardiac markers and [callous-unemotional] traits is perhaps only present in juveniles.”
Researchers do cite some limitations of this study. For one, baseline heart rate information was determined during a single 3-minute-long video clip. However, conducting research with vulnerable populations such as incarcerated people comes with unavoidable constraints, thus researchers deemed this manipulation appropriate and feasible for this study.
The study, “Heart-wired to be cold Exploring cardiac markers of callous-unemotional traits in incarcerated offenders“, was authored by Hanne M. Duindam, DeWayne P. Williams, Jessica J. Asschera, Machteld Hoeve, Julian F. Thayer, and Hanneke E. Creemers.