<p>The Dual Process Theory of Autism proposes that those high in autistic traits, including autistic individuals, have both a reduced propensity for intuition and an enhanced propensity for deliberation. Whilst intuition is rapid and autonomous, many factors impact upon deliberation, and an intolerance of uncertainty may mediate the relationship between autistic traits and propensity for deliberation (but not intuition). Two studies were conducted to explore this hypothesis. In Study 1, 266 non-autistic participants completed an online self-report assessment of autistic traits, propensity for deliberation and intuition and intolerance of uncertainty. Mediation analyses explored the extent to which intolerance of uncertainty mediated the relationship between autistic traits and propensity for deliberation and intuition. Study 2 was a replication of Study 1 with 258 autistic participants. Results from both studies showed that, while higher autistic traits had no direct relationship with propensity for deliberation, this relationship was fully mediated by intolerance of uncertainty. Prospective intolerance of uncertainty (a desire for predictability) specifically was the significant mediator. In addition, higher autistic traits directly related to reduced propensity for intuition. Comparison of Studies 1 and 2 confirmed greater propensity for deliberation and reduced propensity for intuition in the autistic group compared to the non-autistic group, consistent with the Dual Process Theory of Autism. The findings extend the Dual Process Theory of Autism to suggest that a desire for predictability is a key mechanism underpinning enhanced propensity for deliberation in individuals with higher level of autistic traits, including autism.</p>