To elucidate potential relationships between personality and intelligence it is necessary tomove beyond the ad hoc reporting of correlation coefficients and focus instead on testing deductionsfrom well-established theories. To this end the present paper references Eysenck's (1995) theoreticalwork linking the dimension of psychoticism to both psychosis and creative genius. Drawing on thistheory it was argued that the relationship between psychoticism and crystallized ability will beconditional on the level of fluid intelligence. Participants (N = 100) completed the Eysenck PersonalityQuestionniare - Revised (EPQ-R) and the Kaufman Brief Intelligence Test (K-BIT). Moderated multipleregression revealed a significant interaction effect. As expected crystallized ability (K-BIT vocabulary)was negatively related to psychoticism at low levels of fluid ability (K-BIT matrices) and positivelyrelated to psychoticism at high levels of fluid ability. These findings highlight the potential importanceof psychoticism within GfGc investment theory.