SOJ PsychologyOpen Access Research Article problems and difficulties processing specific types of emotional situations or stimuli.Previous research suggests that some children show personality traits and behaviors similar to adults identified as psychopaths, extending the concept of psychopathy downwards and using an adult definition when examining younger children [6][7]. There are also reasons to believe that the factors associated with psychopathy are relatively stable across development. For example, the callous-unemotional traits of psychopathy are potentially noticeable as early as age three [8] and may have a genetic basis [9]. Research into the stability of callousunemotional traits has found that levels of callous-unemotional traits are generally quite stable across childhood (examined as early as seven years of age) into adulthood [10][11][12][13][14][15], particularly for individuals with other concurrent diagnoses such as Conduct Disorder (e.g., [16]). Recently, Fontaine and colleagues identified four different trajectories for the presence of callous-unemotional traits from middle childhood to pre-adolescence [17]. Using a large twin dataset, the authors were able to determine that all four possible trajectories for these traits were found: stable-high, increasing, decreasing, or stable-low. The most common trajectory was stable-low (74.6% of the sample; 59.5% of which were girls) followed by decreasing (13.4%; 37.4% girls) then increasing (7.3%; 33.7% girls) and finally stable-high (4.7%; 19.5% girls). Although genetics accounted for group membership in most cases, environment played a larger role for some (particularly the stable-high females). The presence of both stable and changing trajectories and the mixed influence of genetics and environment highlights the need to better understand the role of these traits, and their outcomes, at an early age and in non-clinical samples (as some of the non-clinical children may reach clinical status with increasing levels of psychopathic traits).The results from [17] also suggest that 'psychopathy' or the presence of 'psychopathic traits' in childhood can be characterized as both dimensional and discrete. The dimensional view of psychopathy presupposes that there are meaningful individual differences both within those who reach clinical status and those that do not. For example, individuals rated as psychopathic by meeting a cutoff score will still show variability in the traits or