Attention to detail: improving extinction by enhancing generalization.

Models of exposure therapy, the gold standard cognitive-behavioural treatment (CBT) for anxiety disorders, suggest that attention may play an important role in the learning that takes place during treatment, and that this may influence the success of treatment. Treatment requires that people generalize what they learn, to other situations that involve stimuli or situations which previously evoked anxiety. This thesis examines the role of attention in the generalization of this learning in experimental and clinical settings.

            First, we review current evidence regarding attention and treatment outcomes following CBT for anxiety disorders (Chapter 1). We then present some of the materials that will support later (Chapters 4.1 and 4.2) experimental analogues of the way in which fear and anxiety develop and are treated, and may then return. 

Chapter 5 paired an aversive unconditional stimulus (US) with a neutral, conditional stimulus (CS), such that participants learn to expect the US to follow the CS. We then extinguished US expectancy by presenting a perceptually similar, generalization stimulus (GS), without the US. GS extinction was insufficient to prevent a return of expectancy of the US when another GS was presented after extinction that possessed some features of the CS that were not present in extinction. Also, the extent of this return correlated with individual differences in self-reported difficulty controlling attention. In chapter 6 we replicate this study in a larger sample by selecting participants on the basis of their self-report attentional control scores.

Again, replicating the same design as chapter 5, chapter 7 examined whether attention, measured in terms of the direction of participants’ gaze, during extinction influenced the rate at which fear extinguishes and then returns after extinction. Participants who spent more time looking at the unique features of the extinction GS during extinction, or who avoided the features in common with CS, showed slower extinction of their fear response and then also showed less return of fear when the second GS was presented after extinction.

In chapter 8 we used verbal cues during extinction to focus participants’ attention towards or away from the features of an extinction stimulus that are shared with an original CS to examine whether this can modify extinction and return of fear. Although the findings were mixed, these verbal instructions seemed sufficient in order to influence the extent to which fear extinguished and returned.

Chapter 9 replicated and expanded upon previous research discussed in the introductory chapter. We found that people who have a tendency to engage their attention toward threatening stimuli in an experimental procedure administered before treatment, also responded better to CBT for anxiety disorders.

In Chapter 10 we present the case for further research in the area of predicting outcomes following CBT for anxiety disorders by using performance in experimental procedures like those presented in this thesis. In Chapter 11, we present a review of the latest evidence concerning pharmaceutical methods for modify the way that the brain processes, encodes and consolidates extinction learning during CBT, to influence the network of neural regions associated with threat-related attention and memories for fear-related events.

Finally, in Chapter 12 we integrate the findings from the investigations within this thesis and consider how they might inform our understanding of anxiety disorders and their treatment as well as what we can learn in terms of modifying or augmenting treatment.