A large body of research has accumulated investigating the possibility of an association between resting heart rate and psychopathic traits, with meta-analysis suggesting a modest, negative association. Some recent research suggests that prior findings of an association between heart rate and psychopathy may be influenced by inclusion of antisocial behavior in the assessment of psychopathic traits. The current study explores this possibility in a longitudinal sample of British males by comparing resting heart rate at age 18 to psychopathy assessed from a Five Factor Model perspective and from the Psychopathy Checklist: Screening Version (PCL:SV) at age 48. Our psychopathic personality scale, created using the Big Five Inventory (BFI), was significantly correlated with the PCL:SV and was most related to the antisocial factor. In correlation analyses, resting heart rate at age 18 was not significantly related to BFI psychopathy, but was positively related to BFI Openness and Conscientiousness, and these associations held up after controlling for childhood SES, BMI at 18, and whether the participant smoked during the age 18 assessment. Additional analyses controlling for smoking status were conducted to address the biasing effect of smoking on heart rate during the age 18 assessment and a significant negative association between resting heart rate and BFI psychopathy emerged. Future research should replicate these results using other normative personality approaches to assess psychopathic traits. Sensitivity: Internal Owing to its translational, clinical, and forensic relevance, the topic of psychopathy has elicited a large amount of attention from scholars across the psychological sciences for decades (Cleckley, 1941; Hare, 1991/2003; Patrick, Fowles, & Krueger, 2009). There have been various lines of research on the topic, including how best to conceive of and measure the construct, including its attendant factor structure (i.e., psychometric debates: see Cooke & Michie, 2001; Hare, 1991; 2003; Skeem & Cooke, 2010) and core features (i.e., debates about the relevance of boldness/fearless dominance: see Lilienfeld et al., 2012; Miller and Lynam, 2012), as well as on the relative contributions of genetic and non-genetic factors to trait variance (Henry et al., 2018; Tuvblad et al., 2018). Consistent evidence suggests that variation in psychopathic tendencies is partly heritable-just like most quantitative human traits (Polderman et al., 2015). While parsing the heritable and environmental components is interesting, further clarifying phenotypic pathways that may contribute to the development of psychopathic traits is just as important if not more so (see Mitchell, 2018). Unfortunately, the evidence base for many of these pathways remains inconsistent. Psychophysiological studies of psychopathic traits have been of some interest to researchers since the 1970s (e.g.
