Values Interventions for Increasing Engagement With What is Feared in Individuals With Specific Phobias

Willingness

In order to capture willingness to engage with feared stimuli three questions were employed, one question for each study task and one for follow up. For example to capture willingness to engage with the virtual reality behavioural approach task, participants were asked: "How willing are you to participate in a virtual reality task involving airplanes?". Answers for all three questions were rated on a scale from 1 (Not willing at all) to 10 (Extremely willing), with higher scores indicating greater willingness levels (i.e., total score: 1 - 10). This approach for developing willingness questions was based on other studies similarly aiming to capture willingness as part of their outcomes using a brief measure (e.g., Fink-Lamotte et al., 2020).

Time frame: Day 1 (During experimental tasks)

Virtual Reality Behavioural Approach Task (VR BAT)

The virtual reality (VR) behavioural approach task was developed for the current study to capture approach behaviour towards airplanes in VR. In total the task included seven steps. Each step depicted a different aspect of flying with associated VR visuals and sounds: 1) airplane stopped engine off, 2) airplane stopped engine running, 3) taxiing, 4) take off, 5) cruising, 6) turbulence and 7) landing, each lasting between 51 and 129 seconds. Approach behaviour was calculated by adding the number of steps participants completed in the VR BAT with total approach behaviour score ranging from 0 to 7.

Time frame: Day 1 (During experimental tasks)

Behavioural Willingness Assessment (BWA)

For this task, participants were presented with the option to book a short complementary flight. This was a categorical response variable: Participants could either book a flight or decline to participate. Booking a flight indicated approach behaviour towards airplanes.

Time frame: Day 1 (During experimental tasks)

Follow up Flying Behaviour

To measure approach behaviour towards airplanes outside the laboratory setting at a one month follow up, one question was employed ("In the past month, have you come in contact with airplanes in any way, such as taking a flight, or booking flight tickets or hotels abroad?") with a "yes" or "no" response (categorical response variable). An affirmative response indicated approach behaviour towards airplanes.

Time frame: One month follow up