Conspiracy theory (CT) beliefs have become an important policy-relevant research area since the events of the COVID-19 pandemic. Increasing interest has been directed towards strategies that might reduce people's susceptibility to conspiratorial beliefs. In this study, we examined whether encouraging a stronger orientation towards critical scientific appraisal of conspiratorial accounts could reduce CT acceptance. After completing baseline measures of COVID-19 related beliefs and analytical and scientific reasoning abilities, a total of 700 adults were randomly allocated to a control or scientific reasoning manipulation. People assigned to the scientific reasoning condition were found to display significantly lower CT belief endorsement post-intervention as compared to the control group. As well as having implications for the design of future intervention studies, the results of this study encourage a greater focus on specific reasoning skills that may be amenable to a psychoeducation approach, in order to further develop methods to prevent CT beliefs.