On a daily basis we are confronted with uncertainty about the outcome of future events. In some uncertain situations we may be able to weigh up the options, predict the outcome, and make an informed choice, whilst in other uncertain situations we have very little information with which to make a judgement. Excessive stress in response to uncertainty is common in anxiety disorders. The collection contains mainly quantitative data in wide format from self-report (i.e. ratings, questionnaire responses) and psychophysiological (i.e. skin conductance, electromygraphy, eyemovements) measures during computerised tasks. Each study is described in the read me document.On a daily basis we are confronted with uncertainty about the outcome of future events. In some uncertain situations we may be able to weigh up the options, predict the outcome, and make an informed choice, whilst in other uncertain situations we have very little information with which to make a judgement. Excessive stress in response to uncertainty is common in anxiety disorders. The term Intolerance of Uncertainty (IU) refers to individual differences in anticipating and reacting to uncertainty, with those high in IU having a more negative reaction to uncertainty than those low in IU. Recent work suggests that understanding IU may be important for the diagnosis and treatment of anxiety disorders. Despite these recent advances, very little is understood about exactly how the processing of uncertainty differs in individuals who are low and high in IU, and how this is related to anxiety. This programme of research characterised how individuals high in IU differ from those low in IU when faced with uncertainty. Some of the questions that were addressed were: 1. Do individuals with higher levels of IU have a broader threshold for detecting uncertainty in their environment than individuals low in IU? 2. Do individuals high in IU differ from those low in IU only when the uncertainty is associated with the potential for something bad to happen or is all uncertainty aversive? 3. Do individuals high in IU cope with uncertainty differently to those low in IU? Do they seek more information to enforce some certainty, or do they avoid uncertain situations altogether? To address these questions, the research made use of state of the art technologies which allowed us to measure what captures people's attention and how they feel whilst they complete computer based tasks that emulate uncertain situations. This research has important implications for theories of anxiety and, importantly, by better understanding the nature of IU and how it is associated with anxiety, the research will help us to design new ways of intervening and treating people with anxiety disorders.