This thesis uses behavioural measures and self-report questionnaires to understand how autistic individuals extract predictive information from their environment, how this predictive information influences perception in autism and how these processes are associated with other clinical features of autism. In chapters 1 & 2, I start the thesis by reviewing the literature on perception, sensory issues, anxiety and learning in autism before moving on to introduce Bayesian models of perception in autism.

In chapters 3, 4 & 5, I present an interrupted search paradigm and demonstrate that autistic individuals did not significantly differ from non-autistic controls in the extent to which prior information guides attention during visual search. These chapters provide a clear case of one aspect of perception in which prior information is used by autistic and non-autistic individuals in a similar manner.

In chapter 6, I present a serial reaction time task which tests whether autistic individuals are able to update predictive information flexibly. The results found that autistic individuals, relative to controls, showed an overall reduction in the extent to which they utilised prior information during the task, but this was not specific to conditions in which they were required to update information about the underlying statistical regularities in the task.

In chapter 7, I use a visual statistical learning task to assess how well participants were able to implicitly acquire high-level predictive statistical information. The results suggest that autistic individuals show a slightly reduced effect of learning when compared to non-autistic controls, but this effect is not specific to high-level information.

In chapter 8, 9 & 10, I present a number of different questionnaire measures for which differences are found between autistic and non-autistic individuals. I used these measures to evaluate the construct of ‘intolerance of uncertainty’ and how it relates to other features of autism before moving on to show that ‘intolerance of uncertainty’ plays a mediating role in clinical features associated with autism, such as anxiety and sensory issues.