Registered ReportHow many times do I need to see to believe? The impact of intolerance of uncertainty and exposure experience on safety-learning and retention in young adults
Introduction
The ability to learn and update threat and safety associations is crucial for maintaining health and wellbeing (Milad and Quirk, 2012; Shin and Liberzon, 2009). Learning threat associations is adaptive and protects us from potentially dangerous situations. However, when a cue ceases to signal threat, it is adaptive to update this association. Failure to do so can result in dysfunctional fears that affect quality of life. Changes in contingency, such as threat to safety, may not always be obvious; it may take a few experiences to recognise that something that once signalled threat may now signal safety. Uncertainty about changes in contingency from threat to safety in the environment may prolong the learning and retention of new safety associations (Bouton, 2002).
Uncertainty has been identified as an important facet of anxiety and stress disorders (Carleton, 2016a, Carleton, 2016b; Dugas et al., 2004; Grupe and Nitschke, 2013). Yet, only recently has the role of individual differences in Intolerance of Uncertainty (IU) (Freeston et al., 1994), a tendency to find uncertainty aversive, been examined in relation to safety-learning (Morriss et al., 2015; Morriss et al., 2016a) and safety-retention (Dunsmoor et al., 2015; Lucas et al., 2018). More specifically, previous work has shown that higher IU is associated with reduced safety-learning, indexed by greater skin conductance responding and pupil dilation to cues that no longer signal threat during the late part of same-day extinction (i.e. last 8 trials) (Morriss, 2019; Morriss et al., 2015; Morriss and van Reekum, 2019). Furthermore, high IU is associated with poorer safety-retention, as higher IU individuals show larger skin conductance responding to cues that no longer signal threat: (1) during next-day extinction (Dunsmoor et al., 2015), and (2) during same-day extinction after reinstatement (Lucas et al., 2018).
Despite these advancements, it is unclear whether individuals who score high in IU have a fundamental difficulty with safety-learning and safety-retention or whether they simply require more exposure than individuals low in IU i.e. extended extinction sessions across a number of days. Given that IU is transdiagnostic (Gentes and Ruscio, 2011; McEvoy and Mahoney, 2012) and that current exposure therapies are based on associative learning principles (Craske et al., 2014), examining the impact of IU upon exposure experience may reveal crucial information relevant to anxiety and stress disorders. In particular, examining IU in relation to safety-retention across multiple extinction sessions is highly relevant due to high rates of relapse in anxiety and stress disorders (Bandelow et al., 2017). We can speculate that IU may be one of the reasons why after treatment some patients with anxiety disorders relapse i.e. individuals with higher IU have difficulty retaining safety information. Therefore, examining the circumstances under which safety-learning and safety-retention can be promoted in individuals with high IU may facilitate new avenues for clinical research on the role of IU and exposure-based treatments for anxiety and stress disorders (Craske et al., 2014; Knowles and Olatunji, 2018).
Here we used an associative threat learning task in a relatively large sample (n = 144), to assess the relationship between self-reported IU and exposure experience on safety-learning and safety-retention. We measured skin conductance responses, pupil dilation and expectancy ratings whilst participants underwent threat acquisition, same-day extinction and next-day extinction phases. We used an aversive sound as an unconditioned stimulus and visual shape stimuli as conditioned stimuli, similar to previous conditioning research including our own (Morriss et al., 2015; Morriss et al., 2016a; Neumann and Waters, 2006). We used a 50% reinforcement rate during acquisition to sustain conditioning during extinction (Grady et al., 2016; Leonard, 1975). Participants were assigned to either a regular exposure (32 trials of same-day and next-day extinction) or extended exposure condition (48 trials of same-day and next-day extinction). We matched individuals based on self-reported IU to ensure we had an equal balance of IU in each condition.
In the regular exposure condition, participants underwent same-day and next-day extinction with 32 trials each, similar to the number of trials used in previous research on same-day extinction (Dunsmoor et al., 2015; Lucas et al., 2018; Morriss et al., 2015; Morriss et al., 2016a). In the extended exposure condition, participants underwent same-day and next-day extinction with 48 trials each, in line with longer extinction sessions used in prior studies i.e. 48–60 trials (Rabinak et al., 2014; Sehlmeyer et al., 2011; Wicking et al., 2016). It has been shown that it is the number of trials not the cumulated duration of trials in extinction that determines safety-learning success (Golkar et al., 2013). Therefore, differences between the regular and extended exposure conditions should be determined by the difference in the number of trials only. Notably, on next-day extinction, the conditioned response fades more quickly due to re-extinction processes (also known as the extinction retention index), therefore less trials are typically used (Lonsdorf et al., 2019). However, we included more trials in order to compare whether safety-learning is improved for individuals high in IU during next-day extinction, compared to same-day extinction.
We hypothesised that during threat acquisition, we would observe conditioned responding, indexed by greater skin conductance responding, pupil dilation and expectancy ratings to the learned threat (CS+) versus safety (CS-) cues. The first aim was to replicate previous findings regarding safety-learning, safety-retention and IU. Based on previous research, we predicted that in the regular exposure condition higher IU would be associated with a larger conditioned response to the CS+ vs. CS- cues during the late part of same-day extinction (i.e. last 8 CS+/CS- trials) (Morriss, 2019; Morriss et al., 2015; Morriss et al., 2016a; Morriss and van Reekum, 2019) and the early part of next-day extinction (first 8 CS+/CS- trials) (Dunsmoor et al., 2015).
The proposed study aimed to extend prior findings by examining whether more exposure promotes safety-learning and retention in individuals with higher levels of IU. The first way we attempted to do this was by including more trials during next-day extinction than in previous research. The second way we attempted to do this was by evaluating whether more exposure promotes safety-learning and retention in individuals with higher levels of IU is by comparing conditions that vary in the number of exposure trials across both same-day and next-day extinction. Specifically, we evaluated the hypothesis that individuals with higher IU would show reduced conditioned responding to the CS+ vs. CS- cues in the extended condition relative to the regular condition during: 1. the late part of same-day extinction (i.e. last 8 CS+/CS- trials); 2. the early and the late parts of next-day extinction. Lastly, we hypothesised that low IU individuals would extinguish similarly regardless of the number of exposure trials on same-day and next-day extinction. These hypotheses were tentative given the lack of research that has examined the impact of more exposure and IU on safety-learning and retention during next-day extinction.
In line with our previous work (for discussion see Morriss et al., 2016a) we tested the specificity of IU effects by controlling for trait anxiety, assessed by the State-Trait Inventory for Cognitive and Somatic Anxiety (STICSA: Ree et al., 2008). We selected the STICSA because it is considered a purer measure of anxiety, compared to other trait anxiety measures which also feature depressive symptomology (Grös et al., 2007).
The experimental protocol and hypotheses were preregistered with the Open Science Framework (https://osf.io/2ugpv/).
Section snippets
Participants
144 participants were recruited from the University of Reading and local area through the use of advertisements and word of mouth (Sex: 86 female, 58 male; M age = 23.99 years, SD = 4.42 years, range = 18–35 years; Ethnicity: 92 White, 29 Asian, 4 Middle Eastern/Arab, 2 Black, 2 Mixed, and 15 not specified; Sexual Orientation: 104 Heterosexual, 20 Sexual Minorities (lesbian/gay/ bisexual/pansexual), 20 not specified). 6 participants did not return for the second day of testing and for 2
Results
For descriptive statistics see Table 1.
Discussion
Here we examined the effect of self-reported IU and exposure experience on safety-learning and -retention. We failed to replicate previous work showing that IU is associated with poorer safety-learning indexed via SCR. We found preliminary evidence for promoted safety-retention in individuals with higher Inhibitory IU who underwent extended exposure, relative to individuals with higher Inhibitory IU who underwent regular exposure, indexed via SCR. These findings further our current
Acknowledgements
This research was supported by: (1) a NARSAD from the Brain and Brain & Behavior Research Foundation, USA (27567) and an ESRC New Investigator, UK Grant (ES/R01145/1) awarded to Jayne Morriss, and (2) an ESRC Future Leaders Grant (ES/L010119/1) awarded to Helen Dodd. The authors would like to thank Jessica Jarvis, Charlotte Elizabeth, Martina Mutti, Laura Bucher and Nicolo Biagi for their help in data collection and data preprocessing. For access to the data please refer to the data supplement
Declaration of competing interest
The authors declare no conflict of interest.
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2022, International Journal of PsychophysiologyCitation Excerpt :Hence, establishing whether IU-related effects are specific to a particular measure or generalize across measures may reveal how IU-related biases modulate classical fear conditioning mechanisms. Secondly, the majority of studies examining IU have focused on immediate extinction training (Dunsmoor et al., 2015; Kanen et al., 2021; Lucas et al., 2018; Morriss, 2019; Morriss et al., 2015, 2016a; Morriss et al., 2019; Morriss and van Reekum, 2019; Morriss et al., 2020; Wake et al., 2020; Wake et al., 2021) and we are, to date, not aware of any study that has examined IU during delayed extinction training. Delayed extinction training more closely models the clinical scenario as exposure-based treatment typically occurs with a time delay after exposure to a traumatic or aversive event.
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2022, Journal of Behavior Therapy and Experimental PsychiatryCitation Excerpt :Combining the current low and high IU conditions with low and high trait anxiety conditions in the same study may clarify if the utility of such linguistic manipulations is unique to IU research and IU-informed clinical practice, or if it could extend to other constructs as well. Finally, an interesting line of research has explored the physiological correlates of IU (e.g. Wake, van Reekum, Dodd, & Morriss, 2020; Morriss, Wake. Lindner, McSorley, Dodd, 2020). Future research could utilise the linguistic manipulation in this study to examine the impact on participants’ skin conductance response, pupil dilation and other physiological reactions when exposed to threatening situations.