Is Fear Generalization influenced by the unknown?

Abstract

Social anxiety is characterized by intense fear or discomfort in social situations, such as public speaking, meeting new people, or interacting in groups (National Institute for Health Excellence and Care, 2013). This fear may be out of proportion to the actual threat and may lead to avoidance of these social situations. This is described as fear generalization and mainly consists of transferring a learned fear response associated with one specific stimulus to a new one (Huggins et al., 2021). Excessive fear generalization (fear overgeneralization) has been proved to be involved in the perpetuation and intensification of social anxiety symptoms (Aslanidou et al., 2023; Lemmens et al., 2021). Actually, some studies distinguish fear and anxiety not only by their duration (phasic vs sustained), but also by the nature of the threat (predictable vs unpredictable) (Schmitz & Grillon, 2012; Wieser et al., 2016). Thereby, it is reasonable to think that all these concepts are related. Previous findings have been proving that the more an event is perceived as unpredictable, the more likely it is of inducing anxiety (Schmitz & Grillon, 2012; Zvolensky et al., 2000). Hence, although it is beyond doubt that fear generalization and unpredictability contribute to the development of social anxiety symptoms, the direct relationship between unpredictability and fear generalization remains unclear. Considering this gap, the purpose of this study is to determine if different levels of unpredictability influence fear generalization and at what extent it affects social anxiety (Lemmens et al., 2021). In this research, two groups were submitted to a fear conditioning paradigm with a generalization test, with different levels of unpredictability. One of the groups was the Unpredictable Group and the other the Predictable Group, with different instructions given at the beginning of the experiment. Subjective (expectancy, valence, and arousal ratings), psychophysiological (skin conductance response, SCR), and visuocortical (steady-state visual evoked potentials, ssVEPs) indices of fear were recorded. Levels of social anxiety (Liebowitz Social Anxiety Scale, LSAS) and intolerance of uncertainty (Intolerance of Uncertainty Scale, IUS) were quantified for each participant, as well as depression (Beck's Depression Inventory, BDI-II) and anxiety levels (State-Trait Anxiety Inventory, STAI). The research showed that predictability of cues did not significantly influence participants' subjective responses to the conditioned stimulus (CS+), regardless of the unpredictability created. In addiction, participants found the CS+ more unpleasant, more arousing, and more likely to be followed by the unconditioned stimulus (US) as indicated by the valence, arousal, and US-expectancy ratings respectively. This study also suggests that the unpredictability of cues does not lead to a notable enhancement in the brain's response to the CS+. In summary, the present study implies that fear generalization is unaffected by unpredictable threats. Although it is unlikely that unpredictability alone may cause fear to overgeneralize, the unpredictability of a threat may not be completely separated from the generalization of fear reactions. This suggests that understanding the underlying mechanisms behind fear reactions could also potentiate the understanding of unpredictable events and the mechanisms related to it. However, further research is required to address the unanswered questions this study raised. Additionally, higher levels of social anxiety symptoms were found to be related with higher intolerance of uncertainty.