The ghosts of the past and future: the propagation of anxious beliefs in episodic memory

Anxiety disorders are characterized by the heightened anticipation of future threat. People with anxiety can go to extremes to avoid feared situations, and fear can spread to related situations. For example, being mocked by a friend may over time lead to someone becoming anxious to engage in social situations in general. In this thesis, I aim to elucidate the mechanisms that drive the anticipation and generalization of future threats by utilizing insights from episodic memory. First, I examined how memory for unique experiences can generalize. Across two experiments, I show that we can memorize an event in high levels of detail. However, with repeated experience we also learn what to expect. This knowledge biases our memory towards what we think is generally true, making it less accurate. This bias is enhanced when we experience high levels of stress. This means that for feared situations, your memory may be more negative than it was because you expected a negative outcome. Beyond memory of your past experiences, episodic memory also enables the imagination of potential future events. In two further experiments, we first showed that while non-anxious people had better memory for imagined emotional future events, anxious people did not and tended to forget more details. Second, we showed that when people imagined positive future events similar to a feared situation they were about to engage in, their memory for that feared event was more positive than when they imagined random positive events. Together, these findings suggest that in anxiety emotional (future) memories may become more generalized and biased towards negative expectations, but that positive future thinking can help reduce negative expectations and ease engaging in feared experiences.