Understanding the varieties of self-generated thought

Although self-generated thought (SGT i.e. cognition unrelated to the here and now) has traditionally been considered as a homogeneous phenomenon, recent findings challenge this assumption by showing that SGT can have both costs and benefits, and that SGT can be linked to both executive control and executive failure. To gain insight into these discrepancies, this PhD tested the hypothesis that SGT is a heterogeneous phenomenon and examined whether the content of the thoughts is one factor underlying the heterogeneities observed. By taking into account the temporal, social and emotional dimensions of SGT content, we were able to systematically identify distinct types of thoughts. In addition, we observed that these different SGT types can have heterogeneous functional outcomes (for example, in terms of their relation to task performance or to measures of self-concept). We also found that these SGT types can have different phenomenological properties, suggesting that heterogeneous cognitive correlates are recruited during the generation of distinct types of thoughts. Finally, we demonstrated that the neural substrates of SGT (as assessed using resting state fMRI) varied according to individual differences in thought content. Altogether, the empirical findings described in the current thesis strongly support the hypothesis that SGT is a heterogeneous phenomenon and highlight that taking into account SGT content allows a better understanding of the neurocognitive underpinnings supporting this subjective experience.