Understanding Heterogeneity in the Content of Self-Generated Thought

Self-generated thought is an integral part of our lives. Previous work suggests that our thoughts consist of diverse content that varies across individuals and over time. It is clear from the literature that what, when and how we think have great implications for our behaviour. It is less clear however, what exactly gives rise to the content of our self-generated thoughts. This thesis aims to discuss the cognitive, neural, dispositional and contextual influences on the contents of our self-generated thoughts. Multidimensional experience sampling is used throughout the empirical chapters of this thesis to identify common patterns in the content of self-generated thought. The first empirical chapter (Chapter 2) investigates the neural mechanisms that might support the content of self-generated thought and examines whether patterns of thought are consistent within individuals. The second empirical chapter (Chapter 3) assesses the influence of context and individual differences on self-generated thought. The last empirical chapter (Chapter 4) investigates the relationship between the persistence of thoughts over time and the ongoing influence of context. The findings suggest that: 1) the ventromedial prefrontal cortex might support episodic and social features of thought content, 2) the content of thought can be shaped by context as well as individual differences and 3) individual differences in the expression of some thought content are more consistent across contexts than other thought content. Additionally, these findings demonstrate that multidimensional experience sampling is a reliable tool to capture the heterogeneity of thought content, influence of context, and individual differences. This thesis provides an original contribution to knowledge by investigating the possible cognitive, neural, contextual, and dispositional determinants of the content of self-generated thought.