The relationship between repetitive negative thinking and shifting internally-oriented attention: Modality matters

There is currently limited theoretical understanding of the mechanisms driving Repetitive Negative Thinking (RNT) transdiagnostically, as most research has examined RNT with a disorder-specific focus (e.g., rumination in depression, worry in generalised anxiety disorder). The Impaired Disengagement Hypothesis (IDH; Koster et al., 2011) proposed a role for impaired attention-shifting in depressive rumination. However, only one published study has examined the relationship between internally-focused attention-shifting from verbal material and RNT; notably, RNT was indexed with disorder-specific measures (Beckwé et al., 2014). That is, no study has examined the link between attention-shifting and RNT assessed by a transdiagnostic measure (not contaminated by disorder-specific features). This thesis aimed to: (i) investigate whether internal verbal attention-shifting biases are related to RNT transdiagnostically, and (ii) determine the content-specificity of any such biases. Study 1 assessed RNT with disorder-specific and transdiagnostic measures, and found no evidence for a reliable relationship between RNT and slowed internal verbal attention-shifting. This study highlighted the need for validated RNT-relevant stimuli; Studies 2a and 2b developed and validated such stimuli. Study 3 used these stimuli to investigate the relationship between verbal RNT and attention-shifting performance; Bayes Factors provided evidence that elevated RNT was not associated with attention-shifting from negative RNT-relevant stimuli. Study 4 aimed to investigate whether this finding was due to modality (i.e., verbal vs. visual) mediating the relationship between attention-shifting and RNT. Given the exploratory nature of this study, its scope was reduced to depressive rumination to allow for the development of a novel in vivo measure of RNT severity across modalities. Data collection was terminated during the pilot phase owing to COVID-19. Overall, the findings of this thesis suggest that the shifting of internal verbal attention is ...