Anxiety, the state of anticipating that a negative event may occur, can be adaptive by promoting harm-avoidant behaviours, and thus preparing an organism to react to threats. However, it can also spiral out of control, resulting in anxiety disorders, with these being one of the most common mental health issues leading to disability. Despite decades of research, progress on treating anxiety seems to have stalled. This lack of progress has been attributed, at least in part, to the gap between animal and human research. By adopting a cognitive task and anxiety manipulation that are translational, this thesis attempts to bridge the aforementioned gap by investigating the neurocognitive effects of adaptive and pathological anxiety in humans; research that could be in turn translated into animals. Towards that goal, a temporal bisection task and a threat-of-shock manipulation were used. The first experimental chapter (Chapter 3) showed that induced anxiety can reliably shift time perception, while fear does not, suggesting that anxiety and fear might be distinct entities. The second experimental chapter (Chapter 4) attempted to tease apart the mechanism of the aforementioned effect, by investigating whether a load manipulation shifts time perception similarly to induced anxiety. Load did not shift time perception; hence it is unclear whether anxiety leads to temporal alterations via ‘overloading’ limited cognitive resources. The third experimental (Chapter 5) chapter explored the neural correlates of the effect of anxiety on time perception using functional magnetic resonance imaging, employing a pilot and a pre-registered study. The findings suggested some overlap between anxiety and task related processing, leaving open the possibility that anxiety impacts cognition via commandeering finite mental resources. The (preliminary) data of the fourth experimental chapter (Chapter 6) suggested that time perception is not impaired in clinically anxious individuals, but working memory is, highlighting potential dissociations between adaptive and pathological anxiety. In the final chapter the findings are discussed in light of neurocognitive theories of anxiety, alongside a discussion of the overall approach of the thesis and future experiments that could clarify disparate findings
