Shifty eyes: the impact of intolerance of uncertainty on gaze behaviour during threat conditioning

Previous research has demonstrated that individuals with high levels of Intolerance of Uncertainty (IU) have difficulty updating threat associations to safety associations. Notably, prior research has focused on measuring IU-related differences in threat and safety learning using arousal-based measures such as skin conductance response. Here we assessed whether IU-related differences in threat and safety learning could be captured using eye-tracking metrics linked with gaze behaviours such as dwelling and scanning. Participants (N = 144) completed self-report questionnaires assessing levels of IU and trait anxiety. Eye movements were then recorded during each conditioning phase: acquisition, extinction learning, and extinction retention. Fixation count and fixation duration served as indices of conditioned responding. Patterns of threat and safety learning typically reported for physiology and self-report were observed for the fixation count and fixation duration metrics during acquisition and to some extent in extinction learning, but not for extinction retention. There was little evidence for specific associations between IU and disrupted safety learning (e.g., greater differential responses to the threat vs. safe cues during extinction learning and retention). While there was tentative evidence that IU was associated with shorter fixation durations (e.g., scanning) to threat vs. safe cues during extinction retention, this effect did not remain after controlling for trait anxiety. IU and trait anxiety similarly predicted greater fixation count and shorter fixation durations overall during extinction learning, and greater fixation count overall during extinction retention. IU further predicted shorter fixation durations overall during extinction retention. However, the only IU-based effect that remained significant after controlling for trait anxiety was that of fixation duration overall during threat extinction learning. Our results inform models of anxiety, particularly in relation to how individual differences modulate gaze behaviour during threat conditioning.