Night owls and dark hearts: The link between chronotype and sadistic tendencies

Diurnal preferences have been found to be associated with a range of adaptive and maladaptive personality traits, including the Big Five personality traits and the Dark Triad. However, no research to date has examined the relationship between morningness-eveningness and sadistic tendencies. According to the niche-specialization hypothesis, individuals with dark personality traits tend to be more active at night because darker environments can help reduce the likelihood of detection or punishment. Given that sadistic tendencies - defined as a person's inclination to derive pleasure from inflicting pain - are a typical dark trait, we anticipate that a nocturnal chronotype would positively correlate with everyday sadism. To test this hypothesis, we conducted two studies utilizing diverse populations and multiple measures of sadism. Study 1 utilized a convenient student sample and self-report questionnaires to provide initial evidence of a correlation between eveningness and sadistic tendencies. Study 2 aimed to validate and generalize these findings by recruiting a broader non-student adult sample and employing a behavioral paradigm less susceptible to self-presentation biases, thereby yielding more ecologically valid and objective evidence for the hypothesized relationship. Together, these findings offer the first empirical support for the association between a night-time chronotype and everyday sadism, thereby endorsing the niche-specialization hypothesis.