A new study has discovered that a desire for exciting and risky experiences is associated with higher levels of antisocial behavior, with little evidence that resting heart rate itself causes antisocial behavior. Published in Aggression and Violent Behavior, these findings suggest that sensation seeking may be a more useful focus for future prevention research.
Antisocial behavior refers to actions that break social rules or disregard other people’s rights and feelings. It can include aggression, deceit, rule-breaking, vandalism and violence. High levels of antisocial behavior during childhood can persist into adulthood and are associated with later criminal behavior and other harmful outcomes.
For decades, researchers have also observed a relationship between antisocial behavior and resting heart rate — the number of heartbeats per minute when a person is calm. People with lower resting heart rates have often been found to show more antisocial behavior. One explanation is that a low heart rate may create an uncomfortable feeling of under-stimulation, leading some people to seek intense experiences. Another possibility is that a low heart rate reflects lower fear or inhibition, making risky or harmful behavior less difficult.
Sensation seeking describes a strong preference for varied, novel and intense experiences, along with a willingness to take risks to obtain them. Previous studies have linked sensation seeking with aggression and rule-breaking, but most were observational. A major goal of this new study was to determine if sensation seeking mediates — or acts as a bridging mechanism for — the established relationship between resting heart rate and antisocial behavior.
Led by Timon G. Udo of Vrije Universiteit Amsterdam, researchers analyzed data from the Netherlands Twin Register. The broad sample included 8,422 adults (66.4% female, average age of 41.9 years). The researchers also examined 1,927 fraternal twins (67.1% female, average age 32.45 years) and a separate group of 2,599 identical twins (74.3% female, average age 34.73 years).
Participants completed questionnaires measuring antisocial behavior and sensation seeking. Because the researchers did not have direct resting heart rate measurements, they used polygenic scores — an estimate of genetic predisposition based on multiple genes — associated with resting heart rate as an indirect substitute. They then used statistical models to compare differences between families and differences between twins within the same family.
In the broad sample, people with higher sensation-seeking scores also tended to report more antisocial behavior. This relationship remained when the researchers analyzed fraternal twins and identical twins. A significant within-family relationship remained even among identical twins, who share 100% of their DNA and much of their early environment. This pattern is consistent with a possible causal contribution from sensation seeking, although it does not establish one.
The evidence for resting heart rate was less convincing. The genetic proxy for resting heart rate predicted antisocial behavior in the broad sample, but in an unexpected direction: a genetic tendency toward a higher resting heart rate was linked to more antisocial behavior. The relationship disappeared in the fraternal-twin analysis, and the proxy did not predict sensation seeking. The researchers therefore found no evidence that sensation seeking mediated a resting heart rate relationship.
Udo and colleagues concluded that “[sensation seeking] could therefore be an effective target for [antisocial behavior] interventions, regardless of [resting heart rate].” This does not mean that sensation seeking should simply be suppressed. The researchers suggested that safer activities could potentially provide stimulation without involving antisocial behavior.
The study had several important limitations. Resting heart rate was not measured directly, and the genetic proxy captured only part of the factors influencing it. Also, antisocial behavior and sensation seeking were assessed using self-report questionnaires. Furthermore, the participants generally scored very low on antisocial behavior, meaning the findings might not apply to severely antisocial populations, and the study could not definitively confirm the direction of cause and effect.
The study, “Adventurous and antisocial hearts: Investigating the causality of associations between antisocial behaviour, resting heart rate and sensation seeking,” was authored by Timon G. Udo, Susanne Bruins, René Pool and Camiel M. van der Laan.