Our finding of increased sensation seeking in winter borns is generally consistent with Joinson and Nettle's finding of increased SSS in young adult winter-borns [28]. However, Joinson and Nettle found a trend of increased sensation seeking in both genders pooled, while we only found the effect in males. Our finding is also inconsistent with past studies where SOB tends to be more, not less related to novelty-seeking among females than males [25]–[27]. It is unclear why our findings diverge from those of past studies. In other studies, SOB has been shown to have opposite effects on different age groups [27], [28], suggesting cohort or development effects. Studies that found stronger effects in females were conducted on university distance learning students in the U.K. [28], general population samples in Sweden [25], [27] and a high school sample from Sweden [26]. The fact that our samples consisted of a subsection of United States (mainly full-time) college students instead of those from a general population may help account for our different findings.
