4. Results
Prior to the estimation of associations between ANS activity and
psychopathic traits we considered sex differences across analyses
variables. Results presented in Table 1 indicate that females had higher
RHR than males. There were no other sex differences in ANS measures.
Males scored significantly higher on two psychopathy trait summary
scores (SRP total, ICU total scores) and four subscale scores (SRP-CA,
ICU-Callousness, ICU-Unemotional, LSRP-Factor 1, and the SSS-Thrill and
Adventure Seeking). This pattern of association suggests that results
present in mixed sex samples may be influenced by sex differences in
heart rate/traits. To account for this possibility and the potential
confounding effects of other demographic characteristics we test
associations between ANS measures and psychopathic with partial
correlations estimated using the {ppcor} package in R version 4.3.1
(Kim, 2015). Partial correlations controlling for sex, race/ethnicity
and age were initially estimated in the full sample. Next, we
re-estimated partial correlations with the sample restricted to females,
while controlling for race/ethnicity and age. We were unable to
replicate associations with the sample restricted to males due to the
small number of males within condition.
*Table 2 *
Results presented in Table 2 indicate differences across tasks in
associations between ANS activity and psychopathic traits in the full
sample. There were no statistically significant negative associations
between HRR to the SSST and psychopathic traits. In contrast, the HRR
during the signaled phase of the countdown task was negatively
associated with SRP-total, SRP-IPM, SRP-ELS, SRP-ASB, and the SSS-total
and disinhibition scores. Variations in associations across tasks were
also observed between SCR and psychopathic traits. There was a negative
association between SCR during the SSST and SRP-IPM and positive
associations between SCR to both signaled and unsignaled noise blasts
during the countdown task and SSS-boredom. Results of analyses also
indicated negative associations between RSC and SRP-ELS and SSS-total
scores, while RHR in the full sample was not associated with any of the
psychopathic traits under consideration here.
*Table 3 *
Next, we restricted the sample to females and performed partial
correlations, controlling for age and ethnicity. Results in Table 3
confirm cross-task variation in associations between ANS and
psychopathic trait measures, but the pattern of association changes
somewhat with the restriction of the sample to females. In the case of
HRR to the countdown task only the negative association between HRR
signaled phase of the countdown task and SRP-total score remained
statistically significant. In addition, there were no statistically
significant associations between HRR during the SSST and psychopathic
traits. Results for analyses testing associations between task related
SCR and psychopathic traits among female again also somewhat relative to
the full sample but continued to indicate cross task differences. The
association between SCR during the SSST and SRP-IPM was again negative
and statistically significant, while there were no longer associations
between SCR and psychopathic traits during the countdown task.
Associations between baseline ANS measures and psychopathic traits with
the sample restricted to females were roughly parallel those in the full
sample. As with the full sample RHR was not associated with psychopathic
traits. The association between RSC and both SRP-ELS and SSS-total
remained significant with the sample restricted to females and the
negative association between SSS-disinhibition and RSC became
statistically significant.